Co-reporter:Paula Cucos, Lorenzo Sorace, Catalin Maxim, Sergiu Shova, Delia Patroi, Andrea Caneschi, and Marius Andruh
Inorganic Chemistry October 2, 2017 Volume 56(Issue 19) pp:11668-11668
Publication Date(Web):September 15, 2017
DOI:10.1021/acs.inorgchem.7b01640
The reactions of cobalt(II) perchlorate with a diazine tetratopic helicand, H4L, in the presence of sodium carbonate afford two coordination polymers constructed from tetranuclear anionic helicates as building blocks: ∞3[Co4L3Na4(H2O)4]·4H2O (1) and ∞2[Co5L3Na2(H2O)9]·2.7H2O·DMF (2). The tetranuclear triple-stranded helicates, {CoII4L3}4–, are connected in 1 by sodium(I) ions and in 2 by sodium(I) and cobalt(II) ions (H4L results from the condensation reaction between 3-formylsalicylic acid and hydrazine). The crystal structures of the two compounds have been solved. In both compounds the anionic helicates interact with the assembling cations through the carboxylato oxygen atoms. Compound 2 features chains resulting from connecting the tetranuclear helicates through cobalt(II) ions. The analysis of the magnetic properties of compounds 1 and 2 evidenced a dominant antiferromagnetic coupling for 1, resulting in a diamagnetic ground state. In contrast, the magnetic behavior of 2 is dominated at low temperature by the CoII ion which connects the antiferromagnetically coupled {CoII4} helical moieties. The ac magnetic measurements for 2 reveal the occurrence of slow relaxation of the magnetization that is due to the single, uncorrelated cobalt(II) ions, which are diluted in an essentially diamagnetic matrix of {CoII4} moieties (ΔEeff = 26.7 ± 0.3 cm–1 with τ0 = (2.3 ± 0.2) × 10–6 s).
Co-reporter:Diana Visinescu;Maria-Gabriela Alexandru;Sergiu Shova;Francesc Lloret;Miguel Julve
Inorganic Chemistry February 20, 2017 Volume 56(Issue 4) pp:2258-2269
Publication Date(Web):February 8, 2017
DOI:10.1021/acs.inorgchem.6b02966
The self-assembly process between the heteroleptic [CrIII(phen)(CN)4]− and [CrIII(ampy)(CN)4]− metalloligands and the heterobimetallic {CuII(valpn)MnII}2+ tecton afforded two heterotrimetallic complexes of formula [{CuII(valpn)MnII(μ-NC)2CrIII(phen)(CN)2}2{(μ-NC)CrIII(phen)(CN)3}2]·2CH3CN (1) and {[CuII(valpn)MnII(μ-NC)2CrIII(ampy)(CN)2]2·2CH3CN}n (2) [phen = 1,10-phenanthroline, ampy = 2-aminomethylpyridine, and H2valpn = 1,3-propanedyilbis(2-iminomethylene-6-methoxyphenol)]. The crystal structure of 1 consists of neutral CuII2MnII2CrIII4 octanuclear units, where two [Cr(phen)(CN)4]− anions act as bis-monodentate ligands through cyanide groups toward two manganese(II) ions from two [CuII(valpn)MnII]2+ units to form a [{Cu(valpn)Mn}2Cr2(CN)4]6+ square motif. Two [Cr(phen)(CN)4]− pendant anions in 1 are bound to the copper(II) ions with cis–trans geometry with respect to the bridging [Cr(phen)(CN)4]− anion. Compound 2 is a sheet-like coordination polymer, where chains constituted by {CrIII(ampy)(CN)4} spacers act as bis-monodentate ligands toward the manganese(II) ions belonging to the {CuII(valpn)MnII} nodes, which are interlinked by another {CrIII(ampy)(CN)4} unit that acts as a bridge between the copper(II) and manganese(II) ions of adjacent chains. Magnetic susceptibility measurements in the temperature range of 1.9–300 K were performed for 1 and 2. An overall antiferromagnetic behavior is observed for 1, the ground spin state being described by a spin triplet from the square motif plus two magnetically isolated spin triplets from the two peripheral chromium(III) ions. Ferrimagnetic chains with interacting spins 1/2 (resulting spin of the trimetallic {CuII(valpn)MnII(μ-NC)CrIII} fragment) and 3/2 (spin from the bis-monodentate [CrIII(ampy)(CN)4]− with weak interchain ferromagnetic interactions across the cyanide bridge between the chromium(III) and the copper(II) ion from adjacent chains [θ = +3.83(2) cm–1]) occur in 2, resulting into a ferromagnetic ordering below 3.5 K. The values of the magnetic coupling between the Cu(II) and Mn(II) ions through the double phenoxide bridge [J = −63.1(2) (1) and −62(3) cm–1 (2)] and those between the Cr(III) and the Mn(II) across the single cyanide bridge [J = −7.08(5) and −4.86(6) cm–1 (1) and −8.59(3) cm–1 (2)] agree with the values reported for these exchange pathways in other magnetostructural studies.
Co-reporter:Teodora Mocanu;Lidia Pop;Niculina D. Hădade;Sergiu Shova;Ion Grosu
CrystEngComm (1999-Present) 2017 vol. 19(Issue 1) pp:27-31
Publication Date(Web):2016/12/21
DOI:10.1039/C6CE02146H
Two rigid tetrahedral organic linkers derived from adamantane have been employed in constructing a 3-D, 4-fold interpenetrated framework featuring a PtS topology, [CuL1(H2O)2](BF4)2·8H2O (1) (L1 = 1,3,5,7-tetrakis{4-(4-pyridyl)phenyl}adamantane), and a 2-fold interpenetrated grid-like coordination polymer, [Mn(hfac)2(L2)0.5] (2) (L2 = 1,3,5,7-tetrakis(4-cyanophenyl)adamantane).
Co-reporter:Teodora Mocanu;Violeta Tudor
CrystEngComm (1999-Present) 2017 vol. 19(Issue 26) pp:3538-3552
Publication Date(Web):2017/07/03
DOI:10.1039/C7CE00798A
The reactions of copper(II) salts with aminoalcohols frequently afford alkoxido-bridged dimers. Neutral (e.g. bis(4-pyridyl) derivatives) or anionic divergent ligands (e.g. polycarboxylate anions, polycyanido-metallates) are employed as spacers. In this paper, a rich variety of structures are reviewed, emphasizing the role played by the denticity of the aminoalcohols and of the linkers, as well as by the accompanying anions, in the network topology. The involvement of coordinative and non-covalent bonds (π–π stacking, argentophilic/aurophilic, π⋯Hg interactions, hydrogen bonds) in sustaining the solid-state architectures is also discussed.
Co-reporter:Andrei A. Patrascu;Sergiu Calancea;Matteo Briganti;Stéphane Soriano;Augustin M. Madalan;Rafael A. Allão Cassaro;Andrea Caneschi;Federico Totti;Maria G. F. Vaz
Chemical Communications 2017 vol. 53(Issue 48) pp:6504-6507
Publication Date(Web):2017/06/13
DOI:10.1039/C7CC03236F
End-off bicompartmental ligands bearing a nitronyl–nitroxide arm have been designed for synthesizing various heterospin molecular systems. These ligands can selectively interact with 3d and 4f metal ions, leading to 2p–4f, 2p–3d, and 2p–3d–4f complexes. The magnetic properties of the 2p–4f and 2p–3d–4f complexes have been investigated and rationalized by theoretical calculations.
Co-reporter:Veacheslav Vieru, Traian D. Pasatoiu, Liviu Ungur, Elizaveta Suturina, Augustin M. Madalan, Carine Duhayon, Jean-Pascal Sutter, Marius Andruh, and Liviu F. Chibotaru
Inorganic Chemistry 2016 Volume 55(Issue 23) pp:12158-12171
Publication Date(Web):November 18, 2016
DOI:10.1021/acs.inorgchem.6b01669
The polynuclear compounds containing anisotropic metal ions often exhibit efficient barriers for blocking of magnetization at fairly arbitrary geometries. However, at variance with mononuclear complexes, which usually become single-molecule magnets (SMM) under the sole requirement of a highly axial crystal field at the metal ion, the factors influencing the SMM behavior in polynuclear complexes, especially, with weakly axial magnetic ions, still remain largely unrevealed. As an attempt to clarify these conditions, we present here the synthesis, crystal structures, magnetic behavior, and ab initio calculations for a new series of NiII–LnIII–WV trimetallics, [(CN)7W(CN)Ni(H2O)(valpn)Ln(H2O)4]·H2O (Ln = Y 1, Eu 2, Gd 3, Tb 4, Dy 5, Lu 6). The surprising finding is the absence of the magnetic blockage even for compounds involving strongly anisotropic DyIII and TbIII metal ions. This is well explained by ab initio calculations showing relatively large transversal components of the g-tensor in the ground exchange Kramers doublets of 1 and 4 and large intrinsic tunneling gaps in the ground exchange doublets of 3 and 5. In order to get more insight into this behavior, another series of earlier reported compounds with the same trinuclear [WVNiIILnIII] core structure, [(CN)7W(CN)Ni(dmf)(valdmpn)Ln(dmf)4]·H2O (Ln = GdIII 7, TbIII 8a, DyIII 9, HoIII 10), [(CN)7W(CN)Ni(H2O)(valdmpn)Tb(dmf)2.5(H2O)1.5]·H2O·0.5dmf 8b, and [(CN)7W(CN)Ni(H2O)(valdmpn)Er(dmf)3(H2O)1]·H2O·0.5dmf 11, has been also investigated theoretically. In this series, only 8b exhibits SMM behavior which is confirmed by the present ab initio calculations. An important feature for the entire series is the strong ferromagnetic coupling between Ni(II) and W(V), which is due to an almost perfect trigonal dodecahedron geometry of the octacyano wolframate fragment. The reason why only 8b is an SMM is explained by positive zero-field splitting on the nickel site, precluding magnetization blocking in complexes with fewer axial Ln ions. Further analysis has shown that, in the absence of ZFS on Ni ion, all compounds in the two series (except those containing Y and Gd) would be SMMs. The same situation arises for perfectly axial ZFS on Ni(II) with the main anisotropy axis parallel to the main magnetic axis of Ln(III) ions. In all other cases the ZFS on Ni(II) will worsen the SMM properties. The general conclusion is that the design of efficient SMMs on the basis of such complexes should involve isotropic or weekly anisotropic metal ions, such as Mn(II), Fe(III), etc., along with strongly axial lanthanides.
Co-reporter:Samira G. Reis, Matteo Briganti, Stéphane Soriano, Guilherme P. Guedes, Sergiu Calancea, Carmen Tiseanu, Miguel A. Novak, Miguel A. del Águila-Sánchez, Federico Totti, Fernando Lopez-Ortiz, Marius Andruh, and Maria G. F. Vaz
Inorganic Chemistry 2016 Volume 55(Issue 22) pp:11676-11684
Publication Date(Web):November 4, 2016
DOI:10.1021/acs.inorgchem.6b01616
Binuclear complexes with general formula [Ln2(hfac)6(H2O)2(dppnTEMPO)] (LnIII = Gd, Tb, and Dy) have been obtained using the paramagnetic ligand 1-piperidinyl-4-[(diphenylphosphinyl)amino]-2,2,6,6-tetramethyl (dppnTEMPO) as a bridge. One of the lanthanide ions is ferromagnetically coupled with the TEMPO moiety. Two of the complexes (Dy and Tb) show slow relaxation of the magnetization, and the non-magneto-equivalence of the two LnIII ions was clearly observed. The ab initio CASSCF calculations were employed to confirm this behavior, as well as to rationalize the Ln–Rad interaction. The simulations of the magnetic properties were allowed by the insights given by the calculations. The inequivalence of the TbIII ions was also proved by emission spectroscopy.
Co-reporter:Diana Visinescu, Maria-Gabriela Alexandru, Augustin M. Madalan, Ie-Rang Jeon, Corine Mathonière, Rodolphe Clérac and Marius Andruh
Dalton Transactions 2016 vol. 45(Issue 18) pp:7642-7649
Publication Date(Web):15 Mar 2016
DOI:10.1039/C6DT00614K
Four isostructural trinuclear 3d–4f–4(5)d heterotrimetallic complexes, with the general formula [L2CuLn(H2O)5(μ-NC)M(CN)7], were obtained from the association of binuclear 3d–4f complexes and {MV(CN)8}3− metalloligands (M = Mo, Ln = La 1; M = W, Ln = La 2; M = Mo, Ln = Gd 3; M = Mo; Ln = Tb 4, where H2L2 = 1,2-ethanediylbis(2-iminomethylene-6-methoxy-phenol)). The metalloligand coordinates through a single-cyanido group at the apical position of the copper(II) ion belonging to the {CuIILnIII} binuclear complex. The analysis of the magnetic data for the La(III) derivatives (compounds 1 and 2), in the 1.85–300 K temperature range, shows a weak ferromagnetic exchange interaction between CuII and MoV/WV ions across the cyanido bridge (JCuM/kB = 3.6(6) K; g = 2.23(5) for 1 and JCuM/kB = 3.8(6) K, g = 2.21(5) for 2, with H = −2JCuMSCu·SM). These results were used to simulate the magnetic properties of compound 3, using the isotropic spin Hamiltonian H = −2JCuMoSCu·SMo − 2JCuGdSCu·SGd. The resulting magnetic interaction between CuII and GdIII ions via the phenoxo-bridge was found to be weakly ferromagnetic (JCuGd/kB = +4.5(2) K with JCuMo/kB = +3.6(2) K, gGd = gCu = 2.00 and gMo = 1.98). The dc magnetic properties for compound 4 also show a predominant ferromagnetic interaction, while the ac magnetic measurements indicate the presence of the slow relaxation of the magnetization below 3.5 K.
Co-reporter:Andrei A. Patrascu, Sergiu Calancea, Rafael A. Allão Cassaro, Stéphane Soriano, Augustin M. Madalan, Catalin Maxim, Miguel A. Novak, Maria G. F. Vaz and Marius Andruh
CrystEngComm 2016 vol. 18(Issue 25) pp:4779-4786
Publication Date(Web):09 May 2016
DOI:10.1039/C6CE00729E
Three new 1-D coordination polymers, [Co(valpn)Gd(hfac)2(IN)]n (1), [Ni(valpn)Gd(hfac)2(IN)]n (2), and [Ni(valpn)Dy(hfac)2(IN)]n (3), were constructed by connecting {MII(valpn)LnIII(hfac)2} nodes through isonicotinato spacers (IN−), with hexafluoroacetylacetonato being hfac and 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol) (H2valpn) being the Schiff base obtained from the condensation reaction between o-vanillin and 1,3-diaminopropane. The synthetic approach relied on the substitution of the acetate ligands from the binuclear precursors [MII(CH3OH)(valpn)LnIII(hfac)2(CH3COO)] with the isonicotinato ligand. The investigation of the magnetic properties of all compounds showed a ferromagnetic interaction attributed to the intranode exchange interaction between the 3d and 4f metal ions. For compound 3, the AC magnetic measurements indicated a field-induced slow relaxation of the magnetization of the [NiIIDyIII] nodes.
Co-reporter:Adrian E. Ion; Simona Nica; Augustin M. Madalan; Sergiu Shova; Julia Vallejo; Miguel Julve; Francesc Lloret
Inorganic Chemistry 2015 Volume 54(Issue 1) pp:16-18
Publication Date(Web):December 18, 2014
DOI:10.1021/ic5025197
Two novel bidimensional coordination polymers, [Co(azbbpy)(4,4′-bipy)0.5(DMF)(NCS)2]·MeOH (1) and [Co(azbbpy)(bpe)0.5(DMF)(NCS)2]·0.25H2O (2), resulted from the assembling of cobalt(II) ions by 1,3-bis(4-pyridyl)azulene, using either 4,4′-bipyridyl or 1,2-bis(4-pyridyl)ethylene as neutral spacers. The cobalt(II) nodes in 1 and 2 act as single-ion magnets (SIMs).
Co-reporter:Gabriela Marinescu, Catalin Maxim, Rodolphe Clérac, and Marius Andruh
Inorganic Chemistry 2015 Volume 54(Issue 12) pp:5621-5623
Publication Date(Web):June 4, 2015
DOI:10.1021/acs.inorgchem.5b00889
New 4d–4f heterometallic complexes with a one-dimensional structure, 1∞[{Ru(valen)(CN)2KRu(valen)(CN)2}{Ln(O2NO)2(CH3OH)3}]·2CH3OH (Ln = Gd, Tb, Dy), have been assembled from the reaction of [K(H2O)2RuIII(valen)(CN)2]·H2O with lanthanide nitrates. The exchange interaction between RuIII and GdIII mediated by the cyanido ligand was determined for the first time and found to be weak and of antiferromagnetic nature.
Co-reporter:Guilherme P. Guedes, Igor F. Santos, Luiza A. Mercante, Nivaldo L. Speziali, Jackson A. L. C. Resende, Alice M. R. Bernardino, Marius Andruh, and Maria G. F. Vaz
Crystal Growth & Design 2015 Volume 15(Issue 3) pp:1027-1030
Publication Date(Web):February 13, 2015
DOI:10.1021/cg5018328
Two new coordination polymers, 1∞[Cu2(L)4(MeOH)]·MeOH (1) and 3∞[Cu(L)2]·5H2O (2), have been obtained exploring the potential of 5-amino-1-phenyl-1H-pyrazole-4-carboxylate (L–) to act as a spacer. The different architectures of these compounds arise from the versatility of this organic ligand. In compound 1, the carboxylato groups (syn-syn bridging mode) and the copper ions generate a binuclear paddle-wheel motif. Each binuclear entity coordinates to another one, through one out of the four pyrazole rings, resulting in double chains. In crystal 2, the organic ligand is coordinated to a copper ion through the carboxylato group (asymmetric chelating) and to another copper ion through the pyrazole nitrogen atom. Compound 2 crystallizes in the hexagonal system with the chiral space group P6122, featuring a quartz-like topology. The magnetic properties of both compounds have been investigated.
Co-reporter:Diana Visinescu, Maria-Gabriela Alexandru, Augustin M. Madalan, Céline Pichon, Carine Duhayon, Jean-Pascal Sutter and Marius Andruh
Dalton Transactions 2015 vol. 44(Issue 38) pp:16713-16727
Publication Date(Web):06 Jul 2015
DOI:10.1039/C5DT01738F
Three families of heterotrimetallic chains (type 1–type 3), with different topologies, have been obtained by reacting the 3d–4f complexes, [{Cu(L1)}xLn(NO3)3] with x = 1 or 2, formed in situ by the reaction of Schiff-base bi-compartmental [CuII(L1)] complexes and lanthanide(III) salts, with (NHBu3)3[M(CN)8] (M = MoV, WV). For type 1 series of compounds, 1-D coordination polymers, with the general formula [{Cu2(valpn)2Ln}{M(CN)8}]·nH2O·mCH3CN (where H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol), result from the association of trinuclear {CuII2LnIII} moieties and [MV(CN)8]3− anions acting as tri-connecting spacers [Ln = La (1), Ce (2), Eu (3), Tb (4), Ho (5), M = Mo; Ln = Tb (6), Ho (7), M = W; m = 0, n = 1.5 (7) and 2 (1–4, 6); n = 1, m = 1 (5)]. The type 2 family has the general formula [{Cu(valdp)Ln(H2O)4}{M(CN)8}]·2H2O·CH3CN (where H2valdp = 1,2-propanediylbis(2-iminomethylene-6-methoxy-phenol)) and also consists of heterotrimetallic chains involving binuclear {CuIILnIII} units linked to [M(CN)8]3− anions coordinating through two cyano groups [Ln = Gd (8), Tb (9), Dy (10); M = Mo; Ln = La (11), Gd (12), Tb (13), Dy (14); M = W]. With large LnIII ions (LaIII and PrIII), the type 3 family of heterotrimetallic compounds are assembled: [{Cu2(valdp)2Ln(H2O)4}{Mo(CN)8}]·nCH3OH·mCH3CN, n, m = 0, Ln = La (15); n = m = 1, Pr (16), in which the trinuclear {CuII2LnIII} nodes are connected to [MoV(CN)8]3− anions that act as tetra-connecting spacers. For TbIII derivatives of the type 1 (compounds 4 and 6), the DC magnetic properties indicate a predominant ferromagnetic CuII–TbIII interaction, while the AC magnetic susceptibility (in the presence of a static magnetic field, HDC = 3000 Oe) emphasize the slow relaxation of the magnetization (Ueff/kB = 20.55 K and τ0 = 5.5 × 10−7 s for compound 4, Ueff/kBT = 15.1 K and τ0 = 1.5 × 10−7 s for compound 6). A predominant ferromagnetic CuII–LnIII interaction was also observed in the type 2 series (compounds 8–10 and 12–14) as a result of the magnetic coupling between copper(II) and lanthanide(III) ions via the phenoxo-bridge. The magnetic behavior for the LaIII derivatives reveals that weak ferromagnetic interactions are also operative between the CuII and the 4d/5d centers.
Co-reporter:Alina S. Dinca, Sergiu Shova, Adrian E. Ion, Catalin Maxim, Francesc Lloret, Miguel Julve and Marius Andruh
Dalton Transactions 2015 vol. 44(Issue 16) pp:7148-7151
Publication Date(Web):20 Mar 2015
DOI:10.1039/C5DT00778J
Two types of oxalato-bridged heterometallic 3d–4f dodeca- and hexanuclear compounds have been obtained by connecting six bi- and, respectively, trinuclear moieties through oxalato bridges arising from the slow decomposition of the L-ascorbic acid.
Co-reporter:Carmen Paraschiv, Andrei Cucos, Sergiu Shova, Augustin M. Madalan, Catalin Maxim, Diana Visinescu, Bogdan Cojocaru, Vasile I. Parvulescu, and Marius Andruh
Crystal Growth & Design 2015 Volume 15(Issue 2) pp:799
Publication Date(Web):December 19, 2014
DOI:10.1021/cg501604c
Four new coordination polymers have been obtained solvothermally from the reactions of Zn(NO3)2·6H2O with 1,2-, 1,3-, or 1,4-benzedicarboxylic acids in the presence of various amino-alcohols: 1∞[Zn2(Htea)2(1,2-bdc)] (1), 1∞[Zn(H3tris)(1,3-bdc)(CH3OH)] (2), 3∞[Zn5(Htea)2(1,3-bdc)3(H2O)]·2.6H2O (3), and 3∞[Zn3(H2dea)2(1,4-bdc)3] (4) (H3tea = triethanolamine, H3tris = tris(hydroxymethyl)aminomethane, H2dea = diethanolamine, 1,2-H2bdc =1,2-benzenedicarboxylic acid, 1,3-H2bdc =1,3-benzenedicarboxylic acid, and 1,4-H2bdc =1,4-benzenedicarboxylic acid). Their crystal structures, thermogravimetric analyses, solid-state transformation to ZnO and characterization of the resultant zinc oxide particles are reported. Compounds 1 and 2 show three-dimensional (3D) supramolecular architectures, generated from the interconnection of the zigzag (in 1) and respectively the linear (in 2) chains through hydrogen bonding interactions. The crystal structure of 3 revealed the presence of five different types of zinc atoms that are successively linked through carboxilato or alkoxo bridges in a helicoidal chain running along the crystallographic a axis. Both right-handed (P) and left-handed (M) helices are present in the crystal, and they are alternately interconnected by pairs of isophthalato bridges, resulting in channels of hexagonal shape, filled with water molecules. Compound 4 has a 3D structure in which linear centrosymmetric {Zn3(H2dea)2}6+ nodes are joined by terephthalate bridges. Owing to its porous network, compound 3 was tested in two selective reactions: photooxidation of phenol to hydroquinone and aerobic photooxidative condensation of benzylamine to N-benzylidenebenzylamine.
Co-reporter:Alina-Elena Ghionoiu, Delia-Laura Popescu, Catalin Maxim, Augustin M. Madalan, Ionel Haiduc, Marius Andruh
Inorganic Chemistry Communications 2015 Volume 58() pp:71-73
Publication Date(Web):August 2015
DOI:10.1016/j.inoche.2015.06.003
•Direct atmospheric CO2 capture by a triphenyltin–1,2-bis(4-pyridyl)ethane system is reported.•Formation of a rare trinuclear carbonato-centered Sn(IV) core is described.•New discrete trinuclear complex and 1-D coordination polymer based on C(OSnPh3)3 core have been assembled.Direct atmospheric CO2 capture occurred during the reactions of triphenyltin chloride (Ph3SnCl) with 1,2-bis(4-pyridyl)ethane (bpa) in methanol and aqueous ammonia. Depending on the reaction temperature, 4 °C and room temperature, two different compounds were obtained: a discrete, trinuclear complex, [(Ph3SnCl)2(μ3-CO3)(Ph3Sn)(Hbpa)]·H2O (1), and a coordination polymer 1∞[(Ph3SnCl)(Ph3Sn)2(μ3-CO3)(bpa)]·H2O (2), respectively. X-Ray crystal structure analysis reveals that both compounds contain a rare trinuclear carbonato-centered core C(OSnPh3)3. The supramolecular architecture of compound 1, assembled by hydrogen-bond interactions, is described.Direct atmospheric CO2 capture occurred during the reactions of triphenyltin chloride (Ph3SnCl) with 1,2-bis(4-pyridyl)ethane (bpa) in methanol and aqueous ammonia, with the formation of two compounds featuring the carbonato-centered core C(OSnPh3)3.
Co-reporter:Anca Dumbrava, Rodica Olar, Mihaela Badea, Catalin Maxim, Daniela Ghica, Marius Andruh
Inorganica Chimica Acta 2015 Volume 426() pp:50-54
Publication Date(Web):24 February 2015
DOI:10.1016/j.ica.2014.11.009
•A 1-D nickel(II) coordination polymer was assembled using chromato bridges and phenanthroline as a blocking ligand.•A 3-D coordination polymer has been constructed using from Mn(II) nodes, chromato and 4,4′-bipyridine bridges.•The thermal decomposition of the manganese-chromate derivative leads to a spinel modification, Mn1.5Cr1.5O4.Two new coordination polymers have been assembled using the chromato ions as bridging ligands: 1∞[Ni(phen)(H2O)2(μ-O2CrO2)] 1, and 3∞[Mn(4,4′-bipy)(H2O)(μ-O3CrO)]·H2O 2. In crystal 1 the chromate ions act as bridges connecting two nickel ions through two oxygen atoms, resulting in infinite chains. 1,10-Phenanthroline acts as a blocking ligand. In compound 2, each chromato ion is connected to three manganese ions, resulting in layers which are parallel to the ab plane. The layers are constructed from {Mn3Cr3} meshes, each metal atom being shared between three other meshes. The structure is expanded into the third direction by connecting the inorganic layers through 4,4′-bipy spacers. The thermal decomposition of the two compounds has been investigated.Graphical abstractTwo new coordination polymers have been assembled using the chromato ions as bridging ligands: 1∞[Ni(phen)(H2O)2(μ-O2CrO2)] 1, and 3∞[Mn(4,4′-bipy)(H2O)(μ-O3CrO)]·H2O 2. In crystal 1 the chromate ions act as bridges connecting two nickel ions through two oxygen atoms, resulting in infinite chains. 1,10-Phenanthroline acts as a blocking ligand. In compound 2, each chromato ion is connected to three manganese ions, resulting in layers.
Co-reporter:Liliana Stoicescu, Cătălin Maxim, Mathieu Rouzières, Mihaela Hillebrand, Rodolphe Clérac, Marius Andruh
Polyhedron 2015 Volume 92() pp:111-116
Publication Date(Web):28 May 2015
DOI:10.1016/j.poly.2015.03.019
A novel 2-D coordination polymer [Cu2(L)(N3)3]n1 (HL: 1,5-diaminopentan-3-ol) has been synthesized and its crystal structure and magnetic properties have been studied. The crystal structure of the compound 1 consists of binuclear moieties [Cu2(L)(N3)3] with mixed alkoxido/end-on azido bridges, which are linked by double asymmetric end-on and single asymmetric end-to-end azido bridges, resulting in a 2-D layer extended within the ab crystallographic plane. Variable-temperature magnetic susceptibility data evidence strong antiferromagnetic interaction between the CuII ions within the binuclear units, which are mediated by the two types of bridges (J = −123(2) cm−1, H = −2JS1S2). The experimental value of the exchange coupling constant is confirmed by DFT calculations.A 2-D coordination polymer with a novel topology was synthesized: [Cu2(L)(N3)3]n (HL: 1,5-diaminopentan-3-ol). The copper ions are connected by alkoxido and three types of azido bridges: single end-on (associated with the alkoxido bridge), double asymmetric end-on, and single asymmetric end-to-end. The magnetic investigation reveals a strong antiferromagnetic interaction between the copper ions.
Co-reporter:Dr. Maria-Gabriela Alexru;Dr. Diana Visinescu; Marius Andruh;Dr. Nadia Marino;Dr. Donatella Armentano;Dr. Joan Cano; Francesc Lloret; Miguel Julve
Chemistry - A European Journal 2015 Volume 21( Issue 14) pp:5429-5446
Publication Date(Web):
DOI:10.1002/chem.201406088
Abstract
The use of the [FeIII(AA)(CN)4]− complex anion as metalloligand towards the preformed [CuII(valpn)LnIII]3+ or [NiII(valpn)LnIII]3+ heterometallic complex cations (AA=2,2′-bipyridine (bipy) and 1,10-phenathroline (phen); H2valpn=1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[CuII(valpn)LnIII(H2O)3(μ-NC)2FeIII(phen)(CN)2 {(μ-NC)FeIII(phen)(CN)3}]NO3⋅7 H2O}n (Ln=Gd (1), Tb (2), and Dy (3)) and the trinuclear complex [CuII(valpn)LaIII(OH2)3(O2NO)(μ-NC)FeIII(phen)(CN)3]⋅NO3⋅H2O⋅CH3CN (4) were obtained with the [CuII(valpn)LnIII]3+ assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[NiII(valpn)LnIII(ONO2)2(H2O)(μ-NC)3FeIII(bipy)(CN)]⋅2 H2O⋅2 CH3CN}n (Ln=Gd (5), Tb (6), and Dy (7)) resulted with the related [NiII(valpn)LnIII]3+ precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [CuII(valpn)LaIII(OH2)3(O2NO)(μ-NC)FeIII(phen)(CN)3]+, nitrate counterions, and non-coordinate water and acetonitrile molecules. The heteroleptic {FeIII(bipy)(CN)4} moiety in 5–7 acts as a tris-monodentate ligand towards three {NiII(valpn)LnIII} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the CuIILnIII (1–3) and NiIILnIII (5–7) units, as well as through the single cyanide bridge between the FeIII and either NiII (5–7) or CuII (4) account for the overall ferromagnetic behavior observed in 1–7. DFT-type calculations were performed to substantiate the magnetic interactions in 1, 4, and 5. Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out-of-phase ac signals below 4.0 K in the lack of a dc field, the values of the pre-exponential factor (τo) and energy barrier (Ea) through the Arrhenius equation being 2.0×10−12 s and 29.1 cm−1, respectively. In the case of 7, the ferromagnetic interactions through the double phenoxo (NiII–DyIII) and single cyanide (FeIII–NiII) pathways are masked by the depopulation of the Stark levels of the DyIII ion, this feature most likely accounting for the continuous decrease of χMT upon cooling observed for this last compound.
Co-reporter:Lívia B. L. Escobar, Guilherme P. Guedes, Stéphane Soriano, Nivaldo L. Speziali, Alessandro K. Jordão, Anna Claudia Cunha, Vitor F. Ferreira, Catalin Maxim, Miguel A. Novak, Marius Andruh, and Maria G. F. Vaz
Inorganic Chemistry 2014 Volume 53(Issue 14) pp:7508-7517
Publication Date(Web):June 25, 2014
DOI:10.1021/ic5008044
In this work we report the synthesis, crystal structures, and magnetic behavior of 2p–3d–4f heterospin systems containing the nitroxide radical 4-azido-2,2,6,6-tetramethylpiperidine-1-oxyl radical (N3tempo). These compounds were synthesized through a one-pot reaction by using [Cu(hfac)2], [Ln(hfac)3] (hfac = hexafluoroacetylacetonate, Ln = DyIII, TbIII or GdIII), and the N3tempo radical. Depending on the stoichiometric ratio used, the synthesis leads to penta- or trimetallic compounds, with molecular formulas [Cu3Ln2(hfac)8(OH)4(N3tempo)] (Ln = Gd, Tb, Dy) and [CuLn2(hfac)8(N3tempo)2(H2O)2] (Ln = Gd, Dy). The magnetic properties of all compounds were investigated by direct current (dc) and alternating current (ac) measurements. The ac magnetic susceptibility measurements of TbIII- and DyIII-containing compounds of both families revealed slow relaxation of the magnetization, with magnetic quantum tunneling in zero field.
Co-reporter:Paula Cucos, Floriana Tuna, Lorenzo Sorace, Iulia Matei, Catalin Maxim, Sergiu Shova, Ruxandra Gheorghe, Andrea Caneschi, Mihaela Hillebrand, and Marius Andruh
Inorganic Chemistry 2014 Volume 53(Issue 14) pp:7738-7747
Publication Date(Web):July 7, 2014
DOI:10.1021/ic501051q
Three new binuclear helicates, [M2L2]·3DMF (M = Co(II), 1, Zn(II), 3) and [Cu2L2]·DMF·0.4H2O (2), have been assembled using the helicand H2L that results from the 2:1 condensation reaction between o-vanillin and 4,4′-diaminodiphenyl ether. The metal ions within the binuclear helicates are tetracoordinated with a distorted tetrahedral geometry. Direct current magnetic characterization and EPR spectroscopy of the Co(II) derivative point to an easy axis type anisotropy for both Co(II) centers, with a separation of at least 55 K between the two doublets. Dynamic susceptibility measurements evidence slow relaxation of the magnetization in an applied dc field. Since the distance between the cobalt ions is quite large (11.59 Å), this is attributed in a first instance to the intrinsic properties of each Co(II) center (single-ion magnet behavior). However, the temperature dependence of the relaxation rate and the absence of slow dynamics in the Zn(II)-doped sample suggest that neither the simple Orbach mechanism nor Raman or direct processes can account for the relaxation, and collective phenomena have to be invoked for the observed behavior. Finally, due to the rigidization of the two organic ligands upon coordination, the pure zinc derivative exhibits fluorescence emission in solution, which was analyzed in terms of fluorescence quantum yields and lifetimes.
Co-reporter:Adrian E. Ion, Simona Nica, Augustin M. Madalan, Catalin Maxim, Miguel Julve, Francesc Lloret and Marius Andruh
CrystEngComm 2014 vol. 16(Issue 3) pp:319-327
Publication Date(Web):24 Sep 2013
DOI:10.1039/C3CE41592A
Four new heterometallic 3d–4f complexes have been obtained using bi- and trinuclear building blocks: 1∞[Ni(L1)Gd(NO3)3(azbbpy)]·CH3CN (1), [Zn(L1)Eu(NO3)3(azbbpy)]·H2O (2), 1∞[(CuL2)2Gd(NO3)2(dca)] 3 and 1∞[(NiL2)2Dy(H2O)4(oxy-bbz)]NO3·3H2O (4), [H2L1 = 1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol), H2L2 = 2,6-di(acetoacetyl)pyridine, azbbpy = 1,3-bis(4-pyridyl)azulene, dca− = dicyanamide anion, and oxy-bbz = the dianion of the 4,4′-oxy-bis(benzoic) acid]. 1 and 2 represent the first complexes containing 1,3-bis(4-pyridyl)azulene as a ligand. 1, 3, and 4 are one-dimensional coordination polymers constructed from heterometallic nodes connected by the exo-dentate ligands. Helical chains are assembled in the case of 4. The analysis of the packing diagram for 1 reveals the occurrence of π–π stacking interactions established between the azulene rings from neighboring chains, which lead to supramolecular layers. The magnetic properties of 3 in the temperature range 1.9–300 K have been investigated. Intra-node ferromagnetic interactions are established between the CuII and GdIII ions (J = +2.7 cm−1, Ĥ = −J(ŜCu·ŜGd + ŜCu·ŜGd).
Co-reporter:Traian D. Pasatoiu, Alberto Ghirri, Augustin M. Madalan, Marco Affronte and Marius Andruh
Dalton Transactions 2014 vol. 43(Issue 24) pp:9136-9142
Publication Date(Web):20 Mar 2014
DOI:10.1039/C4DT00515E
Two original heterooctanuclear [NiII4LnIII4] complexes (LnIII = SmIII, GdIII) have been obtained starting from the [NiII(valpn)(H2O)2] mononuclear precursor [H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)] and the corresponding lanthanide nitrates, in the presence of azide anions, through slow capture of atmospheric CO2. Three weak and competitive exchange interactions, JGdGd, JGdNi, JNiNi, make the ground state of this magnetic system degenerate at cryogenic temperature and zero field. This, along with the high spin of GdIII, lead to a significant magnetocaloric effect spread in the temperature range 1 to 20 K (ΔSm[0–7 T, 3.5 K] = 19 J kg−1 K−1).
Co-reporter:Andreea Dogaru, Céline Pichon, Rodica Ababei, Dmitri Mitcov, Catalin Maxim, Loïc Toupet, Corine Mathonière, Rodolphe Clérac, Marius Andruh
Polyhedron 2014 Volume 75() pp:146-152
Publication Date(Web):17 June 2014
DOI:10.1016/j.poly.2014.03.025
New bidimensional cyanido-bridged heterometallic coordination polymers, [{Co(L1)}3{Fe(CN)6}2]·6CH3OH·6H2O (1) and [{Fe(L2)}3{Co(CN)6}2]·2CH3OH·13H2O (2), have been assembled following a building-block approach (L1 and L2 are macrocyclic ligands obtained by the template condensation between 2,6-diacetylpyridine and 3,4-dioxaoctane-1,8-diamine, and triethylenetetramine, respectively). The crystal structure of 1 consists of honeycomb layers, each [FeIII(CN)6]3− unit connecting three [Co(L1)]2+ nodes through three facial cyanido groups. On the other hand, the self-assembly process between [CoIII(CN)6]3− and [Fe(L2)]2+ ions affords 2-D layers with a brick wall topology. Each [CoIII(CN)6]3− metalloligand is surrounded by three [Fe(L2)]2+ units, which adopt a meridional configuration around the cobalt metalloligand for compound 2. The magnetic properties of the two compounds have been investigated. Compound 1 shows a ferromagnetic order below 3 K. The magnetic properties of 2 are characteristic of non-interacting high spin FeII ions, which exhibit a moderate uniaxial magnetic anisotropy (D/kB = −5.5 K).New bidimensional cyanido-bridged heterometallic coordination polymers, [CoII3FeIII2] and [FeII3CoIII2], have been assembled following the building-block approach. The cobalt(II)–iron(III) derivative shows a ferromagnetic order below 3 K.
Co-reporter:Guilherme P. Guedes, Stéphane Soriano, Luiza A. Mercante, Nivaldo L. Speziali, Miguel A. Novak, Marius Andruh, and Maria G. F. Vaz
Inorganic Chemistry 2013 Volume 52(Issue 15) pp:8309-8311
Publication Date(Web):July 5, 2013
DOI:10.1021/ic401479d
Four tetranuclear heterometallic complexes, [CoII2Mn2III(dpm)4(MeO)6] (1) and [LnIII2MnIII2(dpm)6(MeO)6(MeOH)n], where Ln = Gd (2, n = 2), Tb (3, n = 2), and Dy (4, n = 0), have been obtained following the same general synthetic route, namely, the one-pot reaction between 2,2,6,6-tetrametil-3,5-heptanodione (Hdpm), MnCl2 and CoCl2 or Ln(NO3)3 in the presence of sodium methoxide. Within the four compounds, the metal ions bridged by methoxide ligands display a defect-diheterocubane core. Compounds 1, 3, and 4 show slow relaxation of the magnetization below 4 K.
Co-reporter:Maria-Gabriela Alexandru, Diana Visinescu, Sergiu Shova, Francesc Lloret, Miguel Julve, and Marius Andruh
Inorganic Chemistry 2013 Volume 52(Issue 19) pp:11627-11637
Publication Date(Web):September 25, 2013
DOI:10.1021/ic4019794
Three isomorphous two-dimensional (2D) coordination polymers of general formula {[NiII(valpn)LnIII(NO3)(H2O)(μ-NC)4WIV(bipy)(CN)2]·xH2O·yCH3CN}n have been synthesized by reacting Ph4P[WV(CN)6(bipy)] with the heterodinuclear [NiIILnIII(valpn)(O2NO)3] complexes [H2valpn = 1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol), bipy = 2,2′-bipyridine, and Ln = Gd (1), Dy (2), and Tb (3) with x = 2 (1), 3.9 (2), and 3.35 (3) and y = 2.50 (1), 2 (2), and 1.8 (3)]. Their crystal structures consist of [NiIILnIII] 3d-4f nodes which are connected by [WIV(bipy)(CN)6]2– diamagnetic linkers resulting from the reduction of WV to WIV during the reaction process. The Ni(II) and Ln(III) ions occupy the inner and outer coordination sites of the dideprotonated valpn ligand, respectively, and they are doubly bridged by the phenoxo oxygen atoms of such a ligand. The value of Ni(II)···Ln(III) separation through this bridge is 3.4919(10) (1), 3.4760(10) (2), and 3.4799(9) (3) Å, and those of the angles at the bridgehead phenoxo atoms are 106.6(2) and 107.3(2) (1), 106.9(2), and 107.8(2) (2) and 106.5(2)–106.8(2)° (3). Each W(IV) is eight-coordinated with a bidentate bipy molecule and six cyanide-carbon atoms building a somewhat distorted square antiprism environment. The rare-earth cations are nine-coordinated, the donor atoms describing a monocapped square antiprism for 1 and 3 and a tricapped trigonal prism for 2. Magnetic susceptibility measurements in the temperature range 1.9–300 K show the occurrence of ferromagnetic interactions between the Ni(II) and Ln(III) ions in 1–3. Frequency-dependent alternating susceptibility signals were observed for the DyIII derivative below 8.0 K under an applied dc field of 2500 G indicating the presence of slow magnetic relaxation with values of the pre-exponential factor (τ0) and energy barrier (E#) of ca. 5.7 × 10–8 s and 15.9 cm–1, respectively. Complex 2 constitutes the first example of a 2D 3d-4f heterobimetallic single molecule magnet (SMM).
Co-reporter:Adrian E. Ion, Simona Nica, Augustin M. Madalan, Francesc Lloret, Miguel Julve and Marius Andruh
CrystEngComm 2013 vol. 15(Issue 2) pp:294-301
Publication Date(Web):24 Oct 2012
DOI:10.1039/C2CE26469B
Three new complexes have been obtained using C3-symmetric trinuclear complexes as tectons; [Cu3(felden)(NCS)3(dmf)3] (1), [Cu3(felden)(mand)3]·(C2H5)2O (2), and [Cu3(felden)(dca)3(C2H5OH)]·2H2O (3) (H3felden is the Schiff base resulting from the condensation of 2,4,6-triformylphloroglucinol with N,N-dimethylethylenediamine, mand− is the anion of the R-mandelic acid and dca− is the dicyanamide anion). Compounds 1 and 2 are discrete trinuclear species, while compound 3 is a 2D coordination polymer, constructed from trinuclear nodes and dicyanamido spacers. The variable-temperature magnetic properties of 1–3 have been investigated and they reveal the occurrence of weak antiferromagnetic interactions between the copper(II) ions (−J values ranging from 0.90 to 2.40 cm−1) whose size and trend are dependent on the intramolecular copper–copper separation and nature of the basal chromophore at each copper atom.
Co-reporter:Masood Sarwar, Augustin M. Madalan, Carmen Tiseanu, Ghenadie Novitchi, Catalin Maxim, Gabriela Marinescu, Dominique Luneau and Marius Andruh
New Journal of Chemistry 2013 vol. 37(Issue 8) pp:2280-2292
Publication Date(Web):27 Mar 2013
DOI:10.1039/C3NJ00199G
Sixteen new 3d–4f binuclear complexes have been obtained using two Schiff-base ligands, Hvalampy and Hvalaepy, derived from the reaction of o-vanillin and 2-aminomethyl-pyridine or 2-(2-aminoethyl)-pyridine, respectively. Hvalaepy ligand: [Zn(valaepy)2Sm(O2NO)3]·CH3CN 1; [Ni(valaepy)2Eu(O2NO)3(H2O)]·CH3CN 2; [Ni(valaepy)2Gd(O2NO)3(H2O)]·CH3CN 3; [Ni(valaepy)2Dy(O2NO)3(H2O)]·CH3CN 4; [Ni(valaepy)2Ho(O2NO)3(H2O)]·CH3CN 5; [Cu(valaepy)2Eu(O2NO)3]·CH3CN 6; [Cu(valaepy)2Gd(O2NO)3]·CH3CN 7; Hvalampy ligand: [Zn(valampy)2Pr(O2NO)3]·CH3CN 8, [Zn(valampy)2Sm(O2NO)3]·CH3CN 9; [Zn(valampy)2Gd(O2NO)3]·CH3CN 10; [Zn(valampy)2Tb(O2NO)3]·CH3CN 11; [Zn(valampy)2Dy(O2NO)3]·CH3CN 12; [Zn(valampy)2Eu(O2NO)3]·CH3CN 13; [Ni(valampy)2La(O2NO)3(H2O)2]·2H2O 14, [Ni(valampy)2Sm(O2NO)3(H2O)2]·2H2O 15; [Ni(valampy)2Eu(O2NO)3(H2O)]·2CH3CN 16. The crystal structures of the sixteen compounds can be described as resulting from the coordination of two valaepy− (or valampy−) ligands to the 3d metal ions through two phenoxo oxygen atoms and nitrogen atoms, arising from the pyridyl and azomethynic groups. In all these compounds the 3d and 4f metal ions are bridged by the phenoxo oxygen atoms. The comparative analysis of the crystal structures shows several differences, which arise mainly from the stereochemical preference of the 3d metal ions. These ions arrange the two organic ligands in positions that favour or not the coordination of the methoxy groups to the lanthanide ions. The magnetic properties of compounds 2, 3, 4, 5, 7, 14, 15, and 16 have been investigated. The exchange interactions between NiII and GdIII in 3, and between CuII and GdIII in 7 were found to be ferromagnetic (JNiGd = 1.56 cm−1; JCuGd = 4.94 cm−1; H = −JSGdSM). For the 3d–4f binuclear complexes derived from the Hvalampy ligand (namely 8–13) the photoluminescence (PL) properties were investigated in the Vis spectral region. The results provide evidence for the relatively stronger antenna effect in 9 and 11 compared to 8, 12 and 13.
Co-reporter:Violeta Tudor, Teodora Mocanu, Floriana Tuna, Augustin M. Madalan, Catalin Maxim, Sergiu Shova, Marius Andruh
Journal of Molecular Structure 2013 Volume 1046() pp:164-170
Publication Date(Web):23 August 2013
DOI:10.1016/j.molstruc.2013.04.036
•Reactions of copper(II) with aminoalcohols in the presence of nitrogen ligands are investigated.•The crystal structures of six new bis-alkoxo binuclear complexes are described.•A strong ferromagnetic coupling was found with one compound.Six binuclear alkoxo-bridged complexes have been obtained and cystallographically characterized. The binuclear species are spontaneously assembled by reacting copper perchlorate with an aminoalcohol (monoethanolamine, Hmea, or propanolamine, Hpa) in the presence of various co-ligands: 4-phenyl-pyridine (4-phpy) 4-amino-pyridine (4-apy) dipyridylamine (dpyam), 2,3-bis(2-pyridyl)pyrazine (dpp). The six new compounds have the following formulas: [Cu(mea)(4-phpy)(ClO4)]21, [Cu(pa)(4-phpy)2]2(ClO4)22, [Cu(pa)(4-apy)(ClO4)]23, [Cu(mea)(dpyam)]2(ClO4)24, [Cu(pa)(dpyam)]2(ClO4)25, and [Cu(mea)(dpp)]2(ClO4)2·CH3OH 6. Except compound 1, the binuclear entities in crystals 2 – 6 are centrosymmetric, with pentacoordinated copper ions. In compound 1, one copper is pentacoordinated, while the other one is hexacoordinated. The perchlorate ions play different functions (monodentate and bridging in 1, monodentate in 3, uncoordinated in 2, 4, 5 and 6. The magnetic properties of compound 1 have been investigated and reveal a quite strong ferromagnetic coupling between the copper ions (J = + 81.9 cm−1, H = −JS1S2).
Co-reporter:Alina S. Dinca, Julia Vallejo, Sergiu Shova, Francesc Lloret, Miguel Julve, Marius Andruh
Polyhedron 2013 Volume 65() pp:238-243
Publication Date(Web):28 November 2013
DOI:10.1016/j.poly.2013.08.049
A new dodecanuclear complex, [{(HL)(L)(dmf)ZnIIDyIII(dmf)(H2O)}6]·3dmf·4.2H2O has been assembled using a supramolecular compartmental ligand (H3L results from the condensation reaction of 3-formylsalicylic acid and hydroxylamine). The six DyIII ions describe an octahedron that is inscribed into the octahedron generated by the zinc(II) ions each DyIII ion from this motif behaving as a single ion magnet.A new dodecanuclear complex, [ZnII6DyIII6], has been assembled using a supramolecular compartmental ligand, each DyIII ion from this motif behaving as a single ion magnet.
Co-reporter:Alina S. Dinca ; Alberto Ghirri ; Augustin M. Madalan ; Marco Affronte
Inorganic Chemistry 2012 Volume 51(Issue 7) pp:3935-3937
Publication Date(Web):March 12, 2012
DOI:10.1021/ic3001762
A novel dodecanuclear complex, [{(HL)(L)(DMF)CuIIGdIII(DMF)(H2O)}6]·6DMF (1; DMF = N,N-dimethylformamide), has been obtained using the ligand resulting from the condensation of 3-formylsalicylic acid with hydroxylamine (H3L). The exchange interaction between the phenoxo-bridged CuII and GdIII ions is weak ferromagnetic (J = +1.01 cm–1). The combination of a high-spin ground state with small anisotropy leads to a significant magnetocaloric effect [−ΔSm(0–7 T) = 23.5 J K g–1 K–1 at ∼2 K].
Co-reporter:Maria-Gabriela Alexandru ; Diana Visinescu ; Augustin M. Madalan ; Francesc Lloret ; Miguel Julve
Inorganic Chemistry 2012 Volume 51(Issue 9) pp:4906-4908
Publication Date(Web):April 20, 2012
DOI:10.1021/ic300544m
The first 3d–4f–5d heterotrimetallic complexes using [WV(bipy)(CN)6]− as a metalloligand were synthesized (bipy = 2,2′-bipyridine). The structural and magnetic properties of three [CuIILnIIIWV] complexes (Ln = Gd, Ho, Tb) are discussed.
Co-reporter:Elena Ilyes ; Mihaela Florea ; Augustin M. Madalan ; Ionel Haiduc ; Vasile I. Parvulescu
Inorganic Chemistry 2012 Volume 51(Issue 15) pp:7954-7956
Publication Date(Web):July 25, 2012
DOI:10.1021/ic301139j
A neutral 3D metal–organic framework, 3∞[Cu2(mand)2(hmt)]·H2O (1), was constructed from binuclear Cu2O2 alkoxo-bridged nodes, generated by the doubly deprotonated mandelic acid. The nodes are connected by hexamethylenetetramine (hmt) spacers, which act as biconnective bridging ligands, and by carboxylato groups. Channels are observed along the crystallographic c axis. The water molecules from the channels can be easily removed, preserving the architecture of the crystal, which is stable up to 280 °C. The Langmuir surface area was found to be 610 m2 g–1. The sorption ability of 1 was investigated using H2 and CO2.
Co-reporter:Catalin Maxim, Floriana Tuna, Augustin M. Madalan, Narcis Avarvari, and Marius Andruh
Crystal Growth & Design 2012 Volume 12(Issue 3) pp:1654-1665
Publication Date(Web):February 8, 2012
DOI:10.1021/cg2016947
Five new CuII–AgI, CuII–CuI, and ZnII–AuI complexes have been obtained starting from copper(II) and, respectively, zinc(II) complexes with (NNO) Schiff-base ligands: [{(H2O)(saldmen)Cu}{(NC)Ag(CN)}] 1, 1∞[{Cu2(salaepipH)2(μ-CN)}{μ-[Ag(CN)2]}](ClO4)2·4H2O 2, 1∞[{(salaepy)Cu}{μ-[Ag(CN)2]}] 3, 1∞[{(salaepy)Cu}{μ-[Cu(CN)2]}] 4, [(salaepy)Zn-NCAuCN]2·H2O 5. The Schiff-base ligands (Hsaldmen, Hsalaepip, Hsalaepy) have been obtained by reacting the salicylaldehyde with N,N-dimethyletylenediamine, N-(2-aminoethyl)piperazine, and, respectively, 2-(2-aminoethyl)-pyridine. The structures of compounds 1 and 5 consist of discrete bi- and, respectively, tetranuclear species. The analysis of the packing diagram for crystal 1 reveals the formation of supramolecular double chains sustained by hydrogen-bond interactions involving the aqua ligand. Compounds 2, 3, and 4 are one-dimensional coordination polymers. The structure of 2 consists of chains constructed from {Cu(salaepip)} nodes bridged alternatively by [Ag(CN)2]− and CN– ions, resulted from the partial decomposition of the silver complex. The 3-D architecture of the crystal is constructed from 1-D coordination polymers, [{Cu2(salaepipH)2(μ-CN)}{μ-[Ag(CN)2]}]n2n+, which are connected by three water molecules that form a triangular water cluster, resulting in a scaffold-like structure with large channels. Compounds 3 and 4 are similar. Their structures can be described as resulting from zigzag anionic chains, [M(CN)2]nn– (M = AgI or CuI), with three-coordinated silver(I) or copper(I) ions, to which monocationic complexes, {(salaepy)Cu}, are attached. The cryomagnetic properties of compounds 1 and 2 have been investigated. Weak antiferromagnetic interactions (J = −2.8 cm–1, H = –JS1S2) mediated by hydrogen bonds are observed for compound 1. The cyanido bridge connecting the basal coordination sites of two copper(II) ions in 2 mediates a moderate antiferromagnetic coupling (J = −55.2 cm–1). Compound 5 exhibits blue luminescence (λ = 464 nm, λex = 400 nm).
Co-reporter:Traian D. Pasatoiu, Augustin M. Madalan, Marian Zamfirescu, Carmen Tiseanu and Marius Andruh
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 32) pp:11448-11456
Publication Date(Web):13 Jun 2012
DOI:10.1039/C2CP41026E
Heterobimetallic [ZnIILnIII] complexes have been obtained using a compartmental Schiff-base ligand, H2valdmpn, resulting from the 2:1 condensation between o-vanillin and 2,2-dimethyl-propilenediamine: [Zn(H2O)(valdmpn)Sm(O2NO)3] 1, [Zn(H2O)(valdmpn)Tb(O2NO)3] 2a, [Zn(H2O)(valdmpn)Tb(O2NO)3]·H2O 2b, and [Zn(H2O)(valdmpn)Gd(O2NO)3]·H2O 3. The crystal structures of 1, 2b, and 3 have been solved. Compounds 1 and 2a crystallize in a non-centrosymmetric space group (P212121), being isomorphous. Crystals 2b and 3 are also isomorphous (space group P). The complex entities in the four crystals are similar and their structures consist of binuclear species with the pentacoordinated zinc(II) ion hosted into the N2O2 compartment and the lanthanide(III) ion in the large, open compartment, with a coordination number of 10. The photophysical properties of the four compounds have been investigated. Strong visible excited (excitation tails extend up to 420–430 nm) one photon antenna sensitization was obtained with the samarium(III) and terbium(III) derivatives. Following femtosecond Ti:Sapphire laser at λex = 775 nm, both second-harmonic generation at λem = 775/2 nm and two-photon induced emission in the VIS range were obtained, extending thus the excitation range of these complexes from the VIS to the NIR spectral range. The two-photon induced emission and second harmonic generation effect for a samarium(III) complex are reported for the first time.
Co-reporter:Diana Visinescu, Ie-Rang Jeon, Augustin M. Madalan, Maria-Gabriela Alexandru, Bogdan Jurca, Corine Mathonière, Rodolphe Clérac and Marius Andruh
Dalton Transactions 2012 vol. 41(Issue 44) pp:13578-13581
Publication Date(Web):03 Oct 2012
DOI:10.1039/C2DT32081A
The reaction of [Cu(valen)] with Tb(NO3)3 and (Bu3NH)3[W(CN)8] affords two types of crystals: [{W(CN)8}Cu(valen)Tb(OH2)5]·2H2O (1, a discrete trinuclear complex) and [{W(CN)8}Cu(valen)Tb(OH2)4]·CH3CN·H2O (2, an infinite zig-zag chain), both compounds showing slow relaxation of the magnetization (H2valen is the Schiff base resulting from the reaction of o-vanillin with 1,2-ethanediamine).
Co-reporter:Cristian D. Ene, Andreea Lungu, Constantin Mihailciuc, Mihaela Hillebrand, Catalina Ruiz-Pérez, Marius Andruh
Polyhedron 2012 31(1) pp: 539-547
Publication Date(Web):
DOI:10.1016/j.poly.2011.10.007
Co-reporter:Gabriela Marinescu, Marius Andruh, Francesc Lloret, Miguel Julve
Coordination Chemistry Reviews 2011 Volume 255(1–2) pp:161-185
Publication Date(Web):January 2011
DOI:10.1016/j.ccr.2010.08.004
The mononuclear oxalato-containing chromium(III) complexes of general formula [Cr(AA)(C2O4)2]− (AA = α-diimine type ligand) are able to produce a large variety of heterometallic complexes by acting as ligands towards either fully solvated metal ions or preformed cationic complexes with available coordination sites. This review focuses on the structural diversity of the polynuclear complexes (oligonuclear and coordination polymers) which are generated by the bis(oxalato)chromate(III) species, with a special emphasis to their magnetic properties.
Co-reporter:Marius Andruh
Chemical Communications 2011 vol. 47(Issue 11) pp:3025-3042
Publication Date(Web):18 Jan 2011
DOI:10.1039/C0CC04506C
The binuclear complexes (3d–3d, 3d–3d′, 3d–4f) with compartmental ligands can efficiently act as tectons in crystal engineering. Various high nuclearity clusters and coordination polymers can be easily obtained by choosing the appropriate spacers. The main interest in such systems arises from their magnetic and photophysical properties. Moreover, 3d–3d′ and 3d–4f complexes are useful precursors in designing heterotrimetallic systems with relevance in molecular magnetism.
Co-reporter:Traian D. Pasatoiu, Jean-Pascal Sutter, Augustin M. Madalan, Fatima Zohra Chiboub Fellah, Carine Duhayon, and Marius Andruh
Inorganic Chemistry 2011 Volume 50(Issue 13) pp:5890-5898
Publication Date(Web):June 2, 2011
DOI:10.1021/ic2004276
A series of dinuclear [NiIILnIII] Schiff-base complexes (using a Schiff-base dicompartmental ligand derived from o-vanillin [H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)]) with Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and a hydroxo-bridged tetranuclear [NiIIYbIII] are reported. The crystal structures have been solved for 10 dinuclear complexes revealing four arrangements for the dinuclear units, which are modulated by the coordinated solvent molecules and the nitrato-anion interactions. The magnetic behaviors have been investigated, and the nature of the NiII–LnIII exchange interaction has been emphasized by comparison with the behavior of the related [ZnIILnIII] derivatives. This allowed for establishing that the interaction within these compounds is antiferromagnetic with the 4f ions of the beginning of the Ln series and turns ferromagnetic from GdIII toward the end of the series. AC susceptibility investigations clearly show the occurrence of slow relaxation processes of the magnetization close to 2 K for the dinuclear [NiIIDyIII] complex.
Co-reporter:Traian D. Pasatoiu, Carmen Tiseanu, Augustin M. Madalan, Bogdan Jurca, Carine Duhayon, Jean Pascal Sutter, and Marius Andruh
Inorganic Chemistry 2011 Volume 50(Issue 13) pp:5879-5889
Publication Date(Web):June 2, 2011
DOI:10.1021/ic200426w
Herein, we report the synthesis, structural investigation, and magnetic and photophysical properties of a series of 13 [ZnIILnIII] heterodinuclear complexes, which have been obtained employing a Schiff-base compartmental ligand derived from o-vanillin [H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)]. The complexes have been synthesized starting from the [Zn(valpn)(H2O)] mononuclear compound and the corresponding lanthanide nitrates. The crystallographic investigation indicated two structural types: the first one, [Zn(H2O)(valpn)LnIII(O2NO)3], contains 10-coordinated LnIII ions, while in the second one, [Zn(ONO2)(valpn)LnIII(H2O)(O2NO)2]·2H2O, the rare earth ions are nine-coordinated. The ZnII ions always display a square-pyramidal geometry. The first structural type encompasses the larger Ln ions (4f0–4f9), while the second is found for the smaller ions (4f8–4f11). The dysprosium derivative crystallizes in both forms. Luminescence studies for the heterodinuclear compounds containing NdIII, SmIII, TbIII, DyIII, and YbIII revealed that the [Zn(valpn)(H2O)] moiety acts as an antenna. The magnetic properties for the paramagnetic [ZnIILnIII] complexes have been investigated.
Co-reporter:Andrei Cucos, Andrei Ursu, Augustin M. Madalan, Carine Duhayon, Jean-Pascal Sutter and Marius Andruh
CrystEngComm 2011 vol. 13(Issue 11) pp:3756-3766
Publication Date(Web):08 Apr 2011
DOI:10.1039/C1CE05112A
The mononuclear complexes belonging to the [M(valXn)]0/+ family [H2valXn are bicompartmental ligands derived from o-vanillin and 1,2- or 1,3-diamines; M = Ni(II), Cu(II), Au(III)] can efficiently act as receptors towards various hydrogen bond donors. The co-crystallization processes between [Ni(valXn)] complexes and ammonium salts (NH4Z, Z− = ClO4−; PF6−; C6H5NH3ClO4) led to different supramolecular arrangements in the crystals depending on the host:guest molar ratio used in reactions. For a 2:1 stoichiometry, supramolecular dimers were obtained in the crystals: 2[Ni(valen)]·NH4Z (Z− = ClO4−, 1a; Z− = PF6−, 1b), 2[Ni(valphen)]·NH4ClO4·CH3OH 1c, 2[Ni(valmen)]·C6H5NH3ClO43, while for a 1:1 stoichiometry a supercomplex with a quadruple deck architecture resulted: 4[Ni(valen)]·3NH4ClO42. The co-crystallization of the Reinecke salt with mononuclear complexes from the [M(valXn)] family affords the following crystals: [Ni(valen)]2·NH4[Cr(NCS)4(NH3)2]·CH3OH 4, [Ni(valdmpn)]2·NH4[Cr(NCS)4(NH3)2]·2H2O 5, and [Cu(valpn)]·NH4[Cr(NCS)4(NH3)2]·CH3CN 6, in which the [M(valXn)] complexes interact with the ammonium ions and ammonia ligands, resulting in supramolecular chains. The composition and the topology of the supramolecular chain can be changed by replacing the ammonium ion from the Reinecke salt with a cationic receptor, [Au(valpn)]+:[Au(valpn)][Cr(NCS)4(NH3)2] 7.
Co-reporter:Silviu Nastase, Catalin Maxim, Marius Andruh, Joan Cano, Catalina Ruiz-Pérez, Juan Faus, Francesc Lloret and Miguel Julve
Dalton Transactions 2011 vol. 40(Issue 18) pp:4898-4908
Publication Date(Web):28 Mar 2011
DOI:10.1039/C0DT01815E
Three MnIII–MIII (M = Cr and Fe) dinuclear complexes have been obtained by assembling [MnIII(SB)(H2O)]+ and [MIII(AA)(CN)4]− ions, where SB is the dianion of the Schiff-base resulting from the condensation of 3-methoxysalicylaldehyde with ethylenediamine (3-MeOsalen2−) or 1,2-cyclohexanediamine (3-MeOsalcyen2−): [Mn(3-MeOsalen)(H2O)(µ-NC)Cr(bipy)(CN)3]·2H2O (1), [Mn(3-MeOsalen)(H2O)(µ-NC)Cr(ampy)(CN)3][Mn(3-MeOsalen)(H2O)2]ClO4·2H2O (2) and [Mn(3-MeOsalcyen)(H2O)(µ-NC)Fe(bpym)(CN)3]·3H2O (3) (bipy = 2,2′-bipyridine, ampy = 2-aminomethylpyridine and bpym = 2,2′-bipyrimidine). The [M(AA)(CN)4]− unit in 1–3 acts as a monodentate ligand towards the manganese(III) ion through one of its four cyanide groups. The manganese(III) ion in 1–3 exhibits an elongated octahedral stereochemistry with the tetradentate SB building the equatorial plane and a water molecule and a cyanide-nitrogen atom filling the axial positions. Remarkably, the neutral mononuclear complex [Mn(3-MeOsalen)(H2O)2]ClO4 co-crystallizes with the heterobimetallic unit in 2. The values of the MnIII–MIII distance across the bridging cyanide are 5.228 (1), 5.505 (2) and 5.265 Å (3). The packing of the neutral heterobimetallic units in the crystal is governed by the self-complementarity of the [Mn(SB)(H2O)]+ moieties, which interact each other through hydrogen bonds established between the aqua ligand from one fragment with the set of phenolate- and methoxy-oxygens from the adjacent one. The magnetic properties of the three complexes have been investigated in the temperature range 1.9–300 K. Weak antiferromagnetic interactions between the MnIII and MIII ions across the cyanido bridge were found: JMnM = −5.6 (1), −0.63 (2) and −2.4 cm−1 (3) the Hamiltonian being defined as H = −JSMn·SM. Theoretical calculations based on density functional theory (DFT) have been used to substantiate both the nature and magnitude of the exchange interactions observed and also to analyze the dependence of the magnetic coupling on the structural parameters within the MnIII–N–C–MIII motif in 1–3.
Co-reporter:Masood Sarwar, Augustin M. Madalan, Franceso Lloret, Miguel Julve, Marius Andruh
Polyhedron 2011 30(14) pp: 2414-2420
Publication Date(Web):
DOI:10.1016/j.poly.2011.06.011
Co-reporter:Sebastian A. Stoian, Carmen Paraschiv, Nathalie Kiritsakas, Francesc Lloret, Eckard Münck, Emile L. Bominaar and Marius Andruh
Inorganic Chemistry 2010 Volume 49(Issue 7) pp:3387-3401
Publication Date(Web):March 12, 2010
DOI:10.1021/ic902516r
The synthesis and crystallographic characterization of a new family of M(μ-CN)Ln complexes are reported. Two structural series have been prepared by reacting in water rare earth nitrates (LnIII = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho) with K3[M(CN)6] (MIII = Fe, Co) in the presence of hexamethylenetetramine (hmt). The first series consists of six isomorphous heterobinuclear complexes, [(CN)5M-CN-Ln(H2O)8]·2hmt ([FeLa] 1, [FePr] 2, [FeNd] 3, [FeSm] 4, [FeEu] 5, [FeGd] 6), while the second series consists of four isostructural ionic complexes, [M(CN)6][Ln(H2O)8]·hmt ([FeDy] 7, [FeHo] 8, [CoEu] 9, [CoGd] 10). The hexamethylenetetramine molecules contribute to the stabilization of the crystals by participating in an extended network of hydrogen bond interactions. In both series the aqua ligands are hydrogen bonded to the nitrogen atoms from both the terminal CN− groups and the hmt molecules. The [FeGd] complex has been analyzed with 57Fe Mössbauer spectroscopy and magnetic susceptibility measurements. We have also analyzed the [FeLa] complex, in which the paramagnetic GdIII is replaced by diamagnetic LaIII, with 57Fe Mössbauer spectroscopy, electron paramagnetic resonance (EPR), and magnetic susceptibility measurements, to obtain information about the low-spin FeIII site that is not accessible in the presence of a paramagnetic ion at the complementary site. For the same reason, the [CoGd] complex, containing diamagnetic CoIII, was studied with EPR and magnetic susceptibility measurements, which confirmed the S = 7/2 spin of GdIII. Prior knowledge about the paramagnetic sites in [FeGd] allows a detailed analysis of the exchange interactions between them. In particular, the question of whether the exchange interaction in [FeGd] is isotropic or anisotropic has been addressed. Standard variable-temperature magnetic susceptibility measurements provide only the value for a linear combination of Jx, Jy, and Jz but contain no information about the values of the individual exchange parameters Jx, Jy, and Jz. In contrast, the spin-Hamiltonian analysis of the variable-field, variable-temperature Mössbauer spectra reveals an exquisite sensitivity on the anisotropic exchange parameters. Analysis of these dependencies in conjunction with adopting the g-values obtained for [FeLa], yielded the values Jx = +0.11 cm−1, Jy = +0.33 cm−1, and Jz = +1.20 cm−1 (Ŝ1·J·Ŝ2 convention). The consistency of these results with magnetic susceptibility data is analyzed. The exchange anisotropy is rooted in the spatial anisotropy of the low-spin FeIII ion. The condition for anisotropic exchange is the presence of low-lying orbital excited states at the ferric site that (i) effectively interact through spin−orbit coupling with the orbital ground state and (ii) have an exchange parameter with the Gd site with a value different from that for the ground state. Density functional theory (DFT) calculations, without spin−orbit coupling, reveal that the unpaired electron of the t2g5 ground configuration of the FeIII ion occupies the xy orbital, that is, the orbital along the plane perpendicular to the Fe···Gd vector. The exchange-coupling constants for this orbital, jxy, and for the other t2g orbitals, jyz and jxz, have been determined using a theoretical model that relates them to the anisotropic exchange parameters and the g-values of FeIII. The resulting values, jyz = −5.7 cm−1, jxz = −4.9 cm−1, and jxy = +0.3 cm−1 are quite different. The origin of the difference is briefly discussed.
Co-reporter:Traian D. Pasatoiu ; Augustin M. Madalan ; Michael U. Kumke ; Carmen Tiseanu
Inorganic Chemistry 2010 Volume 49(Issue 5) pp:2310-2315
Publication Date(Web):February 2, 2010
DOI:10.1021/ic902169s
The synthesis, structural investigation, and photophysical properties of a new heterobinuclear complex, [Zn(H2O)(valpn)Eu(NO3)3], are reported [H2valpn = 1,3-propanediylbis(2-iminomethylene-6-metoxy-phenol)]. In the absence of the antenna-type sensitization of europium emission at room temperature, the strongest metal-centered emission was obtained following excitation into the 7F0−5D2 transition at 535 nm. In contrast, at 80 K, the strongest emission of europium was obtained by exciting into the maximum of a high-intensity, low-lying ligand-to-metal charge-transfer band (LMCT) located at ∼425 nm. The overall temperature-induced changes of the photophysical properties of europium were assigned to the relative location of the LMCT and 3ππ* ligand states to the europium excited levels. The results may explain the lack of the antenna effects reported for some of the europium complexes with this type of ligand.
Co-reporter:Gabriela Marinescu, Geanina Marin, Augustin M. Madalan, Alis Vezeanu, Carmen Tiseanu and Marius Andruh
Crystal Growth & Design 2010 Volume 10(Issue 5) pp:2096
Publication Date(Web):March 30, 2010
DOI:10.1021/cg901079s
The self-assembly processes between binuclear [Zn2] and [Cu2] complex cations and exo-bidentate ligands [trans-4,4′-azo-pyridine (azpy), 4,4′-bipyridine (4,4′-bipy), 1,2-bis(4-pyridyl)ethane (bpeta), 1,3-bis(4-pyridyl)propane (bpp)] generate two types of complexes: tetranuclear species with a rectangular topology and one-dimensional (1-D) coordination polymers: [{L2(μ-OH)Cu2}(μ-azpy)2{Cu2(μ-OH)L2}][{L2(μ-OH)Cu2(H2O)}(μ-azpy)2{(H2O)Cu2(μ-OH)L2}](ClO4)8 (1); [{L1Cu2(H2O)2}(μ-azpy)2{Cu2L1(H2O)2}](ClO4)4·(azpy)·2H2O (2); 1∞[{Cu2(μ-OH)L3}(μ-bpp)](ClO4)2 (3); 1∞[{L3Zn2(μ-OH)}(μ-4,4′-bipy)](ClO4)2·2H2O (4); 1∞[{L3Zn2(μ-OH)}(μ-bpeta)](ClO4)2 (5a); 1∞[{L3Zn2(μ-OH)}(μ-bpeta)](ClO4)2·THF (5b); 1∞[{L2Zn2(μ-OH)}(μ-4,4′-bipy)2](ClO4)2·2H2O (6) (H2Ln are compartmental Schiff-base ligands resulting from condensation reactions between 2,6-diformyl-p-cresol with, respectively, 1,3-diamino-propane, 2-aminoethyl-pyridine, and N,N-dimethyl-ethylenediamine). The zinc complexes exhibit luminescence properties.
Co-reporter:Ruxandra Gheorghe, Augustin M. Madalan, Jean-Pierre Costes, Wolfgang Wernsdorfer and Marius Andruh
Dalton Transactions 2010 vol. 39(Issue 20) pp:4734-4736
Publication Date(Web):26 Jan 2010
DOI:10.1039/B925636A
By connecting [LCuTb]3+ nodes with [Fe(CN)6]3− spacers a 1-D coordination polymer with slow relaxation of magnetization is obtained (L2− is the N,N′-propylene-bis(3-methoxysalicylideneiminato) anion).
Co-reporter:Traian D. Pasatoiu, Mael Etienne, Augustin M. Madalan, Marius Andruh and Roberta Sessoli
Dalton Transactions 2010 vol. 39(Issue 20) pp:4802-4808
Publication Date(Web):24 Feb 2010
DOI:10.1039/B925425K
A tetranuclear complex and a 1-D coordination polymer with a ladder-like topology have been obtained by connecting [NiIIDyIII] nodes with dicarboxylato ligands: [Ni2(valpn)2Dy2III(pdca)2(NO3)(H2O)6](NO3)·4H2O 1, and ∞1[Ni2(H2O)2(valpn)2Dy2(tfa)3]·4CH3CN 2 (valpn2− = the dianion of the Schiff base resulting from reacting o-vanillin with 1,3-propanediamine; pdca2− = the dianion of 2,6-pyridinedicarboxylic acid; tfa2− = the dianion of the terephthalic acid). The magnetic measurements show a ferromagnetic interaction between NiII and DyIII, and that both compounds behave like SMM with strong tunnelling. The barrier of 2 (17.4 K) is higher than that of 1 (13.6 K).
Co-reporter:Diana G. Branzea, Augustin M. Madalan, Samuele Ciattini, Narcis Avarvari, Andrea Caneschi and Marius Andruh
New Journal of Chemistry 2010 vol. 34(Issue 11) pp:2479-2490
Publication Date(Web):16 Aug 2010
DOI:10.1039/C0NJ00238K
Heterobinuclear [CuIIMnII] and [CuIICoII] cationic complexes can efficiently act as nodes for designing coordination polymers. The crystal structures of two binuclear precursors, [LCuCo(NO3)2] (1) and [LCuMn(NO3)2] (2), have been solved (L2− is the dianion of the Schiff base resulting from the 2:1 condensation of 3-methoxysalicyladehyde with 1,3-propanediamine). The nitrato ligands, coordinated to CoII and, respectively, the MnII ions from the precursors, are easily replaced by exo-dentate ligands, resulting in 1-D coordination polymers: 1∞[L(H2O)CuCo(oxy-bbz)]·CH3CN·C2H5OH (3), 1∞[L(H2O)CuCo(2,5-dhtp)]·CH3CN (5) and ∞[L(H2O)CuMn(ox)]·3H2O (6) (oxy-bbz2− = the dianion of 4,4′-oxy-bis(benzoic) acid; 2,5-dhtp2− = the dianion of 2,5-dihydroxy-terephthalic acid; ox2− = the dianion of the oxalic acid). In the case of the [CuMn] node, the interaction with oxy-bbz2− affords a binuclear complex, [LCuMn(oxy-bbz)(H2O)2] (4).
Co-reporter:Cristian D. Ene, Silviu Nastase, Catalin Maxim, Augustin M. Madalan, Floriana Tuna, Marius Andruh
Inorganica Chimica Acta 2010 Volume 363(Issue 15) pp:4247-4252
Publication Date(Web):10 December 2010
DOI:10.1016/j.ica.2010.06.056
Co-reporter:Violeta Tudor, Augustin Madalan, Vlad Lupu, Francesc Lloret, Miguel Julve, Marius Andruh
Inorganica Chimica Acta 2010 Volume 363(Issue 4) pp:823-826
Publication Date(Web):1 March 2010
DOI:10.1016/j.ica.2009.12.006
A new CoII/CoIII hexanuclear complex, [Co4IICo2III(dea)2(Hdea)4)(piv)4](ClO4)2·H2O 1, has been obtained by reacting cobalt(II) perchlorate, diethanolamine, and pivalic acid (H2dea = diethanolamine and piv = pivalato anion). The cobalt ions are held together by four μ3 and four μ2 alkoxo bridges as well as by four syn–syn carboxylato groups. The hexanuclear motif contains four Co(II) and two Co(III) ions. The {CoII4CoIII2(μ2-O)4(μ3-O)4} core can be described as a four face-sharing monovacant and bivacant distorted heterocubane units. The cobalt(III) ions are hexacoordinated. Two of the cobalt(II) are hexacoordinated, while the two others are pentacoordinated with a bipyramidal stereochemistry. The magnetic properties of 1 have been investigated in the temperature range 1.9–300 K. Compound 1 exhibits an overall antiferromagnetic behaviour with a ground singlet spin state.The crystal structure and the magnetic properties of a new mixed valence CoII/CoIII hexanuclear complex are discussed.
Co-reporter:Marius Andruh, Jean-Pierre Costes, Carmen Diaz and Song Gao
Inorganic Chemistry 2009 Volume 48(Issue 8) pp:3342-3359
Publication Date(Web):April 13, 2009
DOI:10.1021/ic801027q
Heterometallic 3d−4f complexes are of high interest in molecular magnetism: the lanthanide ions bring large and, in most cases, anisotropic magnetic moments. The combination of 3d and 4f metal ions, which differ through their chemistries and stereochemical preferences, leads to a rich variety of heterometal complexes, ranging from discrete entities to 3-D coordination polymers. This paper reviews recent achievements in this field: (i) oligonuclear complexes for studying the nature of the 3d−4f exchange interaction; (ii) construction of single-molecule magnets; (iii) magnetic properties of 3d−4f coordination polymers.
Co-reporter:Catalin Maxim, Corine Mathonière and Marius Andruh
Dalton Transactions 2009 (Issue 37) pp:7805-7810
Publication Date(Web):31 Jul 2009
DOI:10.1039/B905621A
A pentanuclear complex, [Mo(CN)8{CuL1}2{CuL1(H2O)}2]·6H2O 1, and a decanuclear one, [Mo(CN)8{CuL2}3{CuL2(H2O)}]2·10H2O 2, have been obtained following the building-block approach (HL1 and HL2 are tridentate Schiff bases obtained by reacting salicylaldehyde with 2-aminomethyl-pyridine and 2-aminoethyl-pyridine, respectively). Both compounds present reversible photo-induced magnetic properties interpreted as a MoIV–CuII charge transfer. Compound 2 exhibits a lower efficiency of this metal–metal charge transfer than compound 1 attributed to a less flexible structure of 2 compared to 1.
Co-reporter:Cristian D. Ene, Catalin Maxim, Floriana Tuna, Marius Andruh
Inorganica Chimica Acta 2009 Volume 362(Issue 5) pp:1660-1664
Publication Date(Web):1 April 2009
DOI:10.1016/j.ica.2008.08.034
A trinuclear copper(II) complex, [Cu3(2,5-pydc)2(Me5dien)2(BF4)2(H2O)2] · H2O 1, has been constructed from 2,5-pyridine-dicarboxylato bridges (2,5-pydc2−) and N,N,N′,N″,N″-pentamethyl-diethylenetriamine (Me5dien) acting as a blocking ligand. The copper ions, within the centrosymmetric trinuclear cations, are connected by two 2,5-pydc2− bridges, with an intramolecular Cu···Cu separation of 8.432 Å. The central copper ion exhibits an elongated octahedral geometry, with semicoordinated (BF4-) ions, while the terminal ones are pentacoordinated (distorted square-pyramidal geometry). The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the copper(II) ions (J = −5.9 cm−1, H = −JSCu1SCu2 − JSCu2SCu1a).A trinuclear copper(II) complex has been constructed from 2,5-pyridine-dicarboxylato bridges (2,5-pydc2−) and pentamethyl-diethylenetriamine (Me5dien) acting as a blocking ligand. The exchange interaction mediated by the 2,5-pydc2− is antiferromagnetic.
Co-reporter:Diana Visinescu Dr.;AugustinM. Madalan Dr. ;Carine Duhayon Dr.;Jean-Pascal Sutter Dr.;Liviu Ungur;Willem VandenHeuvel;LiviuF. Chibotaru
Chemistry - A European Journal 2009 Volume 15( Issue 44) pp:11808-11814
Publication Date(Web):
DOI:10.1002/chem.200902408
Co-reporter:Silviu Nastase, Catalin Maxim, Floriana Tuna, Carine Duhayon, Jean-Pascal Sutter, Marius Andruh
Polyhedron 2009 28(9–10) pp: 1688-1693
Publication Date(Web):
DOI:10.1016/j.poly.2008.10.033
Co-reporter:Diana G. Branzea, Annalisa Guerri, Oscar Fabelo, Catalina Ruiz-Pérez, Lise-Marie Chamoreau, Claudio Sangregorio, Andrea Caneschi and Marius Andruh
Crystal Growth & Design 2008 Volume 8(Issue 3) pp:941
Publication Date(Web):January 11, 2008
DOI:10.1021/cg700846x
Four new 1D coordination polymers have been constructed from [LCuIIMII] nodes connected by various spacers—the dianion of pyrazole-3,5-dicarboxylic acid (pzdc2−), the trianion of trimesic acid (trim3−), the tetracyanonickelate(II) anion ([Ni(CN)4]2−), and the dicyanamide anion (dca−) [MII = MnII, CoII, and L2− is the dianion of the Schiff-base resulting from the 2:1 condensation of 3-methoxysalicylaldehyde with 1,3-propanediamine, L2− = N,N′-propylene-bis-(3-methoxysalycilideneiminato)]: [LCuMn(pzdc)(CH3OH)(H2O)]·H2O (1), [LCuMn(trim)2/3(CH3OH)2/3(H2O)1/3]·0.66(H2O)·0.66(CH3OH) (2), [LCuCo(dca)2] (3), and [LCu(CH3OH)(H2O)Mn(NC)2Ni(CN)2]·(H2O)(CH3CN) (4). The fifth compound, [{CuL}K{LCu}{Ag(CN)2}] (5), was obtained by reacting [CuL] with K[Ag(CN)2]. The magnetic investigation of compounds 1, 2, and 4 reveals antiferromagnetic CuII−MnII intranode interactions (1, J = −48.9 cm−1; 2, J = −64.7 cm−1; and 4, J = −60.4 cm−1; H = −JSMnSCu), as well as weak internodes antiferromagnetic interactions (for compounds 1 and 4). In the case of 2, a weak ferromagnetic internode interaction occurs through the spin polarization mechanism.
Co-reporter:Geanina Marin, Marius Andruh, Augustin M. Madalan, Alexander J. Blake, Claire Wilson, Neil R. Champness and Martin Schröder
Crystal Growth & Design 2008 Volume 8(Issue 3) pp:964
Publication Date(Web):February 9, 2008
DOI:10.1021/cg700879q
New coordination polymers have been obtained by reaction of alkoxo-bridged copper(II) dimers [Cu2(mea)2]2+ and [Cu2(pa)2]2+ (Hmea = monoethanolamine; Hpa = propanolamine) with divergent pyridyl-containing ligands that act as rigid linear exo-bidentate linkers [p-bis(4-pyridyl)benzene, bpbenz, bis(4-pyridyl)acetylene, bpac, 9,10-bis(4-pyridyl)anthracene, bpanth], as a flexible angular exo-bidentate ligand [bis-(4-pyridyl)disulfide, bpds] or as an exo-tridentate connector [tris(3-pyridyl)benzene, tpyb]. The single crystal X-ray structures of [Cu2(mea)2(bpbenz)(NO3)](NO3)·2.75CH3OH (1), [Cu2(mea)2(bpbenz)2](CF3SO3)2·0.5(bpbenz)·3CH3OH (2), [Cu2(pa)2(bpac)2](ClO4)2 (3), [Cu2(mea)2(bpanth)](CF3SO3)2] (4), [Cu2(mea)2(CH3OH)(H2O)(bpanth)(NO3)2]·CH3OH·H2O (5), [Cu2(mea)2(bpanth)2](ClO4)2·2.5CH3OH (6), [Cu2(mea)2(bpds)2](CF3SO3)2·2CH3OH (7), [Cu2(pa)2(bpds)2](BF4)2 (8), [Cu2(mea)2(tpyb)(ONO2)](NO3)·CH3OH (9), and [Cu2(mea)2(tpyb)(FBF3)](BF4)·CH3OH (10) are reported. Compound 4 exhibits a linear chain structure, while compounds 1, 2, 3, 5, 6, 7, and 8 incorporate extended two-dimensional (2-D) grids. In compound 2 the 2-D networks are disposed parallel to each other, while in compounds 3 and 6 interlocked three-dimensional (3-D) structures resulting from inclined interpenetration of the 2-D sheets are observed. Compounds 7 and 8 consist of layers that pack to give channels running through the solid-state structure. In 9 and 10, the tris(3-pyridyl)benzene ligand interacts with the binuclear nodes to give channels. The role of hydrogen-bonding and stacking interactions in sustaining the supramolecular solid-state architectures in these materials is discussed.
Co-reporter:Augustin M. Madalan, Enric Canadell, Pascale Auban-Senzier, Diana Brânzea, Narcis Avarvari and Marius Andruh
New Journal of Chemistry 2008 vol. 32(Issue 2) pp:333-339
Publication Date(Web):22 Oct 2007
DOI:10.1039/B713030A
The synthesis and crystal structure of the first tetrathiafulvalene (TTF) based radical cation salt containing the heteroleptic paramagnetic anion [CrIII(2,2′-bipy)(C2O4)2]− are reported. In the salt formulated as α′-(BEDT-TTF)2[Cr(C2O4)2(2,2′-bipy)]·CHCl2CH2Cl according to the single-crystal X-ray structure, the BEDT-TTF (bis(ethylenedithio)tetrathiafulvalene) donors are in a mixed valence state and form two types of uniform chains within organic layers. Two overlap modes are observed in these chains, which are canted with respect to the stacking direction, leading to a peculiar α′ packing mode. The anions organize in supramolecular chains sustained by π–π interactions between the bipyridine units. The magnetic behavior of the compound follows a Curie–Weiss law, with a magnetic contribution arising from both cationic and anionic counterparts. Single-crystal electrical transport measurements are in agreement with a semiconductor behavior and have been correlated with extended Hückel tight-binding calculations.
Co-reporter:Catalin Maxim, Traian D. Pasatoiu, Victor Ch. Kravtsov, Sergiu Shova, Christopher A. Muryn, Richard E.P. Winpenny, Floriana Tuna, Marius Andruh
Inorganica Chimica Acta 2008 Volume 361(14–15) pp:3903-3911
Publication Date(Web):1 October 2008
DOI:10.1016/j.ica.2008.03.013
The following Schiff bases were employed as ligands in synthesizing copper(II) and zinc(II) complexes: N-[(2-pyridyl)-methyl]-salicylimine (Hsalampy), N-[2-(N,N-dimethyl-amino)-ethyl]-salicylimine (Hsaldmen), and N-[(2-pyridyl)-methyl]-3-methoxy-salicylimine (Hvalampy). The first two ligands were obtained by reacting salicylaldehyde with 2-aminomethyl-pyridyne and N,N-dimethylethylene diamine, respectively, while the third one results from the condensation of 3-methoxysalicylaldehyde with 2-aminomethyl-pyridine. Four new coordination compounds were synthesized and structurally characterized: [Cu(salampy)(H2O)(ClO4)] 1, [Cu2(salampy)2(H2trim)2] 2 (H2trim− = the monoanion of the trimescic acid), [Cu4(valampy)4](ClO4)4 · 2CH3CN 3, and [Zn3(saldmen)3(OH)](ClO4)2 · 0.25H2O 4. The crystal structure of 1 consists of supramolecular dimers resulted from hydrogen bond interactions established between mononuclear [Cu(salampy)(H2O)(ClO4)] complexes. Compound 2 is a binuclear complex with the copper ions connected by two monoatomic carboxylato bridges arising from two molecules of monodeprotonated trimesic acid. The crystal structure of 3 consists of tetranuclear cations with a heterocubane {Cu4O4} core, and perchlorate ions. Compound 4 is a trinuclear complex with a defective heterocubane structure. The magnetic properties of complexes 1–3 have been investigated. Compound 4 exhibits solid-state photoluminescence at room temperature.Three copper(II) complexes (mono-, bi- and tetranuclear), and one trinuclear zinc(II) complex were obtained by using Schiff-base ligands derived from salicylaldehyde and 3-methoxysalicylaldehyde. The magnetic properties of the copper complexes have been investigated. The zinc compound exhibits solid-state photoluminescence at room temperature.
Co-reporter:Violeta Tudor, Geanina Marin, Francesc Lloret, Victor Ch. Kravtsov, Yurii A. Simonov, Miguel Julve, Marius Andruh
Inorganica Chimica Acta 2008 Volume 361(12–13) pp:3446-3452
Publication Date(Web):1 September 2008
DOI:10.1016/j.ica.2008.03.007
Two new CoII/CoIII complexes, [{CoIICoIII(mea)3}2(bpe)3](ClO4)4 · 1.5CH3OH · 1.5H2O (1) and [Co4IICo3III(dea)6(CH3COO)3](ClO4)0.75(CH3COO)1.25·0.5H2O (2) [Hmea = monoethanolamine H2dea = diethanolamine and bpe = 1,2-bis(4-pyridyl)ethane], have been obtained by reacting cobalt(II) perchlorate (1 and 2), Hmea (1)/H2dea (2), bpe (1) and sodium acetate (2). The crystal structures of 1 and 2 have been solved by single crystal X-ray diffraction. Crystal 1 contains “Chinese lantern”-like shaped cations, resulting by connecting two {CoIICoIII(mea)3} moieties with three flexible bpe ligands. The coordination sphere of the outer cobalt(III) ions is built by three amino groups arising from the mea− ligands, and by three bridging alkoxo-oxygen atoms whereas that of the inner cobalt(II) ions is constituted by the three alkoxo oxygen atoms and by three nitrogen atoms from three bpe ligands. The crystallographic analysis of 2 shows the occurrence of heptanuclear [Co4IICo3III] cations, with a central CoII ion and six peripheral cobalt atoms, three of them being divalent and the other three being trivalent. The magnetic properties of 1 and 2 have been investigated in the temperature range 1.9–300 K. A very weak antiferromagnetic interaction [J = −0.061(2) cm−1] between the high-spin cobalt(II) ions bridged by the bpe ligands occurs in 1 whereas a significant intramolecular ferromagnetic interaction [J = +2.6(1) cm−1] between the high-spin cobalt(II) ions is present in two leading to a low-lying S = 6 spin state. No out-of-phase ac signal was detected for this anisotropic high-spin molecule down to 1.9 K.Two mixed-valence CoII/CoIII clusters have been obtained: a tetranuclear complex, 1, with “Chinese lantern”-like shaped cations and a heptanuclear one, 2, with a star-like topology of the metal centers. Their magnetic properties have been investigated. A ferromagnetic interaction occurs between the cobalt(II) ions in 2.
Co-reporter:Marius Andruh
Chemical Communications 2007 (Issue 25) pp:2565-2577
Publication Date(Web):16 Feb 2007
DOI:10.1039/B616972D
This article focuses on the employment of bi- and trinuclear complexes as building blocks in designing novel heterometallic systems. A large variety of polynuclear complexes, ranging from high-nuclearity clusters to high-dimensionality coordination polymers, can be constructed by taking advantage of the high flexibility of the multimetallic nodes. The following oligonuclear complexes are currently used as tectons in our laboratory: (a) bis(alkoxo)-bridged copper(II) species; (b) homobinuclear species with metal ions held together by end-off, or macrocyclic compartmental ligands; (c) heterometallic complexes with dissymmetric compartmental ligands. The 3d–4f nodes are particularly interesting since the metal ions interact selectively with various spacers. The intra-node exchange interactions, as well as those between the resulting spins, generate interesting magnetic properties.
Co-reporter:Ruxandra Gheorghe, Marius Andruh, Jean-Pierre Costes, Bruno Donnadieu, Marc Schmidtmann, Achim Müller
Inorganica Chimica Acta 2007 Volume 360(Issue 14) pp:4044-4050
Publication Date(Web):1 November 2007
DOI:10.1016/j.ica.2007.05.018
The syntheses and crystal structures of two new hexanuclear complexes are reported: [{(LCuII(ONO2))(LCuII(H2O))NdIII}2(μ-C2O4)](NO3)2 · 6H2O (1) and [{(LNiII(H2O))(N(CN)2)}2PrIII}2(ONO2)](OH) · 2H2O · 3CH3CN (2) (L is the dianion of the Schiff-base resulted from the 2:1 condensation of 3-methoxysalyciladehyde with 1,3-propanediamine). Compounds 1 and 2 were obtained by connecting heterotrinuclear cationic complexes [{LMII}2LnIII]3+ with oxalato or nitrato linkers. The structure of the complex cation in 1 shows two almost linear trinuclear [Cu2Nd] moieties which are linked by a bis-chelating oxalato bridge between the neodymium ions. The hexanuclear cationic moiety in 2 is built up of two heterotrinuclear [Ni2Pr] units that are linked by a nitrato group bridging two praseodymium(III) ions. The spectroscopic (FTIR, UV–Vis) and magnetic properties of 1 and 2 have been investigated.Two new 3d–4f hexanuclear systems, [{(LCu(ONO2))(LCu(H2O))Nd}2(η4-C2O4)](NO3)2 · 6H2O (1), and [{(LNi(H2O){N(CN)2})2Pr}2(η3-NO3)](OH) · 2H2O · 3CH3CN (2), were obtained by interconnecting heterotrinuclear cationic complexes [{LMII}2LnIII]3+ with oxalato and nitrato linkers, respectively; L is the dianion of the Schiff-base resulted from the 2:1 condensation of 3-methoxysalyciladehyde with 1,3-propanediamine.
Co-reporter:Manuel Almeida, Marius Andruh
Inorganica Chimica Acta 2007 Volume 360(Issue 13) pp:3785-3786
Publication Date(Web):1 October 2007
DOI:10.1016/j.ica.2007.03.004
Co-reporter:Carmen Paraschiv, Marius Andruh, Yves Journaux, Zdirad Žak, Nathalie Kyritsakas and Louis Ricard
Journal of Materials Chemistry A 2006 vol. 16(Issue 26) pp:2660-2668
Publication Date(Web):03 May 2006
DOI:10.1039/B602055K
Four new cyano-bridged [MnIIMIIIMnII] heterotrinuclear complexes (MIII = Cr, Fe, Co) have been synthesized and crystallographically characterized: {[(H2O)L1Mn–NC–Cr(CN)4–CN–MnL1(H2O)]}3[Cr(CN)6]·10H2O 1, [(H2O)L2Mn–NC–M(CN)4–CN–MnL2(NCS)]·2H2O 2, [(H2O)L2Mn–NC–Fe(CN)4–CN–MnL2(H2O)](NCS)·1.5H2O 3, and [(H2O)L2Mn–NC–Co(CN)4–CN–MnL2(H2O)](NCS)·1.5H2O 4 (L1 = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene, L2 = 2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene). The crystal structure of 1 consists of independent [MnCrMn] monocations whose charges are counterbalanced by [Cr(CN)6]3− anions. The crystal structure of 2 consists of neutral heterotrinuclear [MnCrMn] species, with the isothiocyanato ion coordinated to one of the manganese atoms. Compounds 3 and 4 are isomorphous. Their crystal structure consists of centrosymmetric [MnMMn] entities, uncoordinated NCS− ions, and solvent molecules. The magnetic properties of the four complexes have been investigated. Compounds 1 and 2 are new examples of systems with an irregular spin state structure, exhibiting the characteristic minimum on the the χMTversusT curves. The exchange interaction between the chromium(III) and the manganese(II) ions is antiferromagnetic (1: J = −9.8 cm−1; 2: J = −6.52 cm−1). For compound 3, the exchange interaction between manganese(II) and iron(III) was found to be ferromagnetic.
Co-reporter:Jean-Pierre Costes, Ruxandra Gheorghe, Marius Andruh, Sergiu Shova and Juan-Modesto Clemente Juan
New Journal of Chemistry 2006 vol. 30(Issue 4) pp:572-576
Publication Date(Web):22 Feb 2006
DOI:10.1039/B518029E
A novel heterobimetallic system, 1∞[LCuIICoII(NCS)2] (1), was obtained by reacting the neutral mononuclear complex [LCu] with cobalt(II) acetate in the presence of potassium thiocyanate (L is the dianion of the Schiff base resulting from the 2 ∶ 1 condensation of 3-methoxysalicylaldehyde with 1,3-propanediamine). The crystallographic investigation of 1 reveals a one-dimensional alternating zig-zag chain-like structure, made of dinuclear {LCuCo} units linked by thiocyanate bridges. The copper(II) ion is pentacoordinate to the N2O2 donor set of the Schiff base ligand in the basal plane, with the apical position occupied by the sulfur atom. The cobalt ion displays a strongly distorted (4 + 2) octahedral geometry. The distance between the phenoxo-bridged metal ions is 3.149(1) Å. The Cu⋯Co distance for the NCS− bridged ions is equal to 6.125(1) Å. The magnetic properties of 1 were investigated in the temperature range 2–300 K and they are explained by a strong antiferromagnetic Cu(II)–Co(II) exchange interaction through the phenoxo bridges and a weak ferromagnetic Cu(II)–Co(II) interaction through the thiocyanato bridges. Several theoretical models are proposed to fit the magnetic data of 1, the most appropriate one being the full matrix diagonalization for a closed-chain of four dinuclear units [CuIICoII], taking into account two different exchange parameters and a D term, which yielded the following results: J = −101.2 cm−1, j = 2.8 cm−1, D = −0.11 cm−1, g = 2.38.
Co-reporter:Augustin M. Madalan, Narcis Avarvari and Marius Andruh
New Journal of Chemistry 2006 vol. 30(Issue 4) pp:521-523
Publication Date(Web):28 Feb 2006
DOI:10.1039/B517989K
Novel supercomplexes are constructed from a mononuclear square planar Ni(II) or Pd(II) complex acting as a host receptor towards the aqua ligand from copper complexes.
Co-reporter:Andrei Cucos;Narcis Avarvari;Yves Journaux;Achim Müller;Marc Schmidtmann
European Journal of Inorganic Chemistry 2006 Volume 2006(Issue 5) pp:
Publication Date(Web):10 JAN 2006
DOI:10.1002/ejic.200500841
Two novel CrIII–NiII heteropolynuclear complexes have been obtained through a self-assembly process involving abinuclear NiII complex with a macrocyclic Robson ligand and Reinecke-type anions (trans-[Cr(NCS)4(NH3)2]–, trans-[Cr(NCS)4(4,4′-bipy)2]–): [Ni2(H2O)2(fsal-33){Cr(NCS)4(NH3)2}]·2H2O (1) and 1∞[Ni2(H2O)2(fsal-33){Cr(NCS)4(4,4′-bipy)2}]n·n[Cr(NCS)4(4,4′-bipy)2] (2). The compartmental ligand results from the condensation of 2,6-diformyl-4-methyl-phenol with 1,3-propanediamine. The crystal structure of 1 consists of neutral tetranuclear [CrNiNiCr] species, where each nickel ion is coordinated in one apical position by a Reinecke anion, and in the other one by an aqua ligand. The distances between the metallic centres in 1 are: Ni···Cr = 6.048 and Ni···Ni = 3.133 Å. Compound 2 contains infinite cationic chains constructed from binuclear [Ni–Ni] nodes, connected through trans-[Cr(4,4′-bipy)2(NCS)4] spacers, and uncoordinated trans-[Cr(NCS)4(4,4′-bipy)2]– ions. The CrIII and NiII ions are connected through 4,4′-bipyridine ligands arising from the Reinecke-type anion. The distance between the nickel and chromium ions within the chain is 11.252 Å. The magnetic properties of 1 have been investigated. Both Ni–Ni and Cr–Ni exchange interactions were found to be antiferromagnetic: JNiNi = –51.3 cm–1; JNiCr = –22.7 cm–1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Co-reporter:Geanina Marin, Victor Kravtsov, Yurii A. Simonov, Violeta Tudor, Janusz Lipkowski, Marius Andruh
Journal of Molecular Structure 2006 Volume 796(1–3) pp:123-128
Publication Date(Web):30 August 2006
DOI:10.1016/j.molstruc.2006.02.047
Three new coordination polymers have been obtained by using alkoxo-bridged copper(II) complexes as nodes, and exo-bidentate ligands as spacers (bis(4-pyridyl)ethane, bpeta, bis(4-pyridyl)propane, bpp, and pyrazine, pyr): [Cu2(pa)2(C2H5OH)2(bpeta)](BF4)21; [Cu4(pa)4(bpp)4(ClO4)2](ClO4)2·2H2O 2; [Cu2(mea)2(pyr)2](CF3SO3)23 (pa stands for the anion of propanolamine, and mea for the one of monoethanolamine). The crystallographic investigation of the three compounds reveals one-dimensional coordination polymers in 1 and 2, and grid-like layers in 3.
Co-reporter:Augustin M. Madalan, Mathias Noltemeyer, Mirela Neculai, Herbert W. Roesky, Marc Schmidtmann, Achim Müller, Yves Journaux, Marius Andruh
Inorganica Chimica Acta 2006 Volume 359(Issue 2) pp:459-467
Publication Date(Web):20 January 2006
DOI:10.1016/j.ica.2005.07.037
Three new homopolynuclear complexes with azido bridges have been obtained by using [Cu(AA)(BB)]+ building-blocks (AA = acetylacetonate; BB = 1,10-phenanthroline or 2,2′-bipyridine). The reaction between [Cu(acac)(phen)(H2O)](ClO4) and NaN3 leads to a mixture of two compounds: a binuclear complex, [{Cu(acac)(phen)}2(μ1,3-N3)](ClO4) · 2H2O (1), and a linear tetranuclear one, [{Cu(acac)(phen)(ClO4)}2{Cu(phen)(μ1,1-N3)2}2] (2). The reaction between [Cu(acac)(bipy)(H2O)](ClO4) and NaN3 affords also a mixture of two compounds: [{Cu(acac)(bipy)}2(μ1,3-N3)]3(ClO4)3 · 3.75H2O (3) and [Cu(acac)(bipy)(N3)][Cu(acac)(bipy)(H2O)](ClO4) (4). The X-ray crystal structures of compounds 1–4 have been solved (for compound 4 the crystal structure was previously reported). In compounds 1 and 3, two {Cu(AA)(BB)} fragments are bridged by the azido anion in an end-to-end fashion. Two isomers, cis and trans with respect to azido bridge, were found in crystal 3. The structure of compound 2 consists of two Cu(II) central cations bridged by two μ1,1-azido ligands, each of them being also connected to a {Cu(acac)(phen)} fragment through another μ1,1-azido ligand. The cryomagnetic properties of the compounds 1 and 2 have been investigated and discussed. The magnetic behaviour of compound 1 shows the absence of any interactions between the metallic ions. In the tetranuclear complex 2, the magnetic interactions between the external and central copper(II) ions(J1), and between the central metallic ions (J2) were found ferromagnetic (J1 = 0.36 cm−1, J2 = 7.20 cm−1).Three new homopolynuclear complexes with azido bridges have been obtained by using [Cu(AA)(BB)]+ building-blocks (AA = acetylacetonate; BB = 1,10-phenanthroline or 2,2′-bipyridine): [{Cu(acac)(phen)}2(μ1,3-N3)](ClO4) · 2H2O (1), [{Cu(acac)(phen)(ClO4)}2{Cu(phen)(μ1,1-N3)2}2] (2), [{Cu(acac)(bipy)}2(μ1,3-N3)]3(ClO4)3 · 3.75H2O (3). The cryomagnetic investigation of the tetranuclear complex, 2, reveals ferromagnetic interactions between the copper ions.
Co-reporter:Diana Visinescu, Jean-Pascal Sutter, Catalina Ruiz-Pérez, Marius Andruh
Inorganica Chimica Acta 2006 Volume 359(Issue 2) pp:433-440
Publication Date(Web):20 January 2006
DOI:10.1016/j.ica.2005.07.041
The heterotrimetallic complex, [{LCuMn(H2O)}{Cr(phen)(C2O4)2}](ClO4) · H2O (1), has been obtained by assembling heterobinuclear cations, [LCuMn]2+, with [Cr(phen)(C2O4)2]− ions (H2L is the compartmental Schiff-base resulting from the stepwise condensation of 2,6-diformyl-p-cresol with ethylenediamine and diethylenetriamine). The copper(II) and manganese(II) ions are hosted into the compartments of the macrocyclic ligand. [Cr(phen)(C2O4)2]− acts as a ligand, being coordinated through one oxalato oxygen atom to the apical position of the square pyramidal copper(II) ion. The cryomagnetic investigation of 1 reveals an antiferromagnetic interaction between CuII and MnII within the compartmental ligand (J = −39 cm−1). The interaction between CuII and CrIII across the oxalato bridge is negligible. The crystal structure of [LCuPb](ClO4)2 · H2O, a useful precursor in obtaining 3d–3d′ complexes, is also reported.A heterotrimetallic complex, [{LCuMn(H2O)}{Cr(phen)(C2O4)2}](ClO4) · H2O, has been obtained by assembling heterobinuclear cations, [LCuMn]2+, with [Cr(phen)(C2O4)2]− ions (H2L is the compartmental Schiff-base resulted from the stepwise condensation of 2,6-diformyl-p-cresol with ethylenediamine and diethylenetriamine).
Co-reporter:Ruxra Gheorghe Dr.;Paula Cucos Dr.;Jean-Pierre Costes Dr.;Bruno Donnadieu;Sergiu Shova Dr.
Chemistry - A European Journal 2006 Volume 12(Issue 1) pp:
Publication Date(Web):1 SEP 2005
DOI:10.1002/chem.200500321
Heteronuclear cationic complexes, [LCuLn]3+ and [(LCu)2Ln]3+, were employed as nodes in designing high-nuclearity complexes and coordination polymers with a rich variety of network topologies (L is the dianion of the Schiff base resulting from the 2:1 condensation of 3-methoxysalycilaldehyde with 1,3-propanediamine). Two families of linkers have been chosen: the first consists of exo-dentate ligands bearing nitrogen-donor atoms (bipyridine (bipy), dicyanamido (dca)), whereas the second consists of exo-dentate ligands with oxygen-donor atoms (anions derived from the acetylenedicarboxylic (H2acdca), fumaric (H2fum), trimesic (H3trim), and oxalic (H2ox) acids). The ligands belonging to the first family prefer copper(II) ions, whereas the ligands from the second family interact preferentially with oxophilic rare-earth cations. The following complexes have been obtained and crystallographically characterized: [LCuII(OH2)GdIII(NO3)3] (1), [{LCuIIGdIII(NO3)3}2(μ-4,4′-bipy)] (2), [LCuIIGdIII(acdca)1.5(H2O)2]⋅13 H2O (3), [LCuIIGdIII(fum)1.5(H2O)2]⋅4 H2O⋅ C2H5OH (4), [LCuIISmIII(H2O)(Hfum)(fum)] (5), [LCuIIErIII(H2O)2(fum)]NO3⋅3 H2O (6), [LCuIISmIII(fum)1.5(H2O)2]⋅4 H2O⋅C2H5OH (7), [{(LCuII)2SmIII}2fum2](OH)2 (8), [LCuIIGdIII(trim)(H2O)2]⋅H2O (9), [{(LCuII)2PrIII}(C2O4)0.5(dca)]dca⋅2 H2O (10), [LCuIIGdIII(ox)(H2O)3][CrIII(2,2′-bipy)(ox)2]⋅9 H2O (11), and [LCuGd(H2O)4{Cr(CN)6}]⋅3 H2O (12). Compound 1 is representative of the whole family of binuclear CuII–LnIII complexes which have been used as precursors in constructing heteropolymetallic complexes. The rich variety of the resulting structures is due to several factors: 1) the nature of the donor atoms of the linkers, 2) the preference of the copper(II) ion for nitrogen atoms, 3) the oxophilicity of the lanthanides, 4) the degree of deprotonation of the polycarboxylic acids, 5) the various connectivity modes exhibited by the carboxylato groups, and 6) the stoichiometry of the final products, that is, the CuII/LnIII/linker molar ratio. A unique cluster formed by 24 water molecules was found in crystal 11. In compounds 2, 3, 4, 9, and 11 the CuII–GdIII exchange interaction was found to be ferromagnetic, with J values in the range of 3.53–8.96 cm−1. Compound 12 represents a new example of a polynuclear complex containing three different paramagnetic ions. The intranode CuII–GdIII ferromagnetic interaction is overwhelmed by the antiferromagnetic interactions occurring between the cyanobridged GdIII and CrIII ions.
Co-reporter:Carmen Paraschiv, Marius Andruh, Sylvie Ferlay, Mir Wais Hosseini, Nathalie Kyritsakas, Jean-Marc Planeix and Nicolae Stanica
Dalton Transactions 2005 (Issue 7) pp:1195-1202
Publication Date(Web):01 Mar 2005
DOI:10.1039/B500231A
Four novel polymeric coordination networks have been obtained through self-assembly processes involving alkoxo-bridged copper(II) species as nodes, and anionic cyano-complexes as linkers: ∞2[{Cu2(pa)2}{M(CN)2}2]
(M = Ag, 1; Au, 2), ∞3[{Cu4(mea)4}{Au(CN)2}4·H2O]
3, and ∞3[{Cu2(pa)2}{Ni(CN)4}]
4
(pa = deprotonated propanolamine; mea = deprotonated monoethanolamine). The supramolecular architectures of compounds 1, 2 and 3 are sustained by argentophilic or strong aurophilic interactions. The solid-state architectures of 1 and 2, which are isomorphous, consist of infinite layers, constructed from binuclear alkoxo-bridged nodes and [M(CN)2]− spacers. The layers are stacked in an offset parallel mode, and are further interconnected through Ag⋯Ag or Au⋯Au contacts (1: Ag⋯Ag 3.015 Å; 2: Au⋯Au 3.069 Å). Compound 3 consists of unique fourfold interpenetrating diamondoid nets. The diamondoid topology is built of heterocubane {Cu4O4} nodes, which are connected by [Au(CN)2]− rods. The Cu–O distances within the {Cu4O4} node vary between 1.927(2) and 2.679(1)
Å, showing unsymmetric bridging of the copper atoms. Aurophilic interactions are established between the bridging and terminal [Au(CN)2]− metalloligands, and connect the interpenetrating nets, resulting in infinite chains of gold atoms (the Au⋯Au distances vary between 3.253 and 3.305 Å). Compound 4 exhibits a 3-D network constructed from {Cu2(pa)2]2+ nodes connected by square-planar [Ni(CN)4]2− ions. Compounds 1, 2 and 4 are weakly paramagnetic. The cryomagnetic investigation of 3 reveals a gradual increase, followed by a decrease of the χMT product, as the temperature is lowered. A superposition of ferro- (J1
=
+20.8 cm−1) and antiferromagnetic (J2
=
−6.4) interactions within the tetranuclear node was found. Antiferromagnetic interactions are established between the tetranuclear nodes (θ
=
−2.99 K).
Co-reporter:Gabriela Marinescu;Diana Visinescu;Andrei Cucos;Yves Journaux;Victor Kravtsov;Yurii A. Simonov;Janusz Lipkowski
European Journal of Inorganic Chemistry 2004 Volume 2004(Issue 14) pp:
Publication Date(Web):5 MAY 2004
DOI:10.1002/ejic.200400061
Two new heterobinuclear complexes, [(bipy)(C2O4)Cr(μ-C2O4)Cu(Hfsaaep)(H2O)]·2H2O (1) and [(phen)(C2O4)Cr(μ-C2O4)Mn(phen)2(N3)]·H2O (2) have been obtained by using bis(oxalato)chromium(III) anions, [Cr(AA)(C2O4)2]−, as building blocks [AA = 2,2′-bipyridine (bipy); 1,10-phenanthroline (phen)]. The crystal structures of the two complexes have been solved. These complexes comprise neutral oxalato-bridged CrIII−CuII and CrIII−MnII units. The [Cr(AA)(C2O4)2]− anion acts as a bidentate ligand toward CuII in compound 1 and as a monodentate ligand toward MnII in compound 2. The copper(II) ion in 1 exhibits a slightly distorted square bipyramidal stereochemistry, with the aqua ligand and one of the bridging oxalato oxygen atoms disposed in the apical positions [Cu(1)−O(1w) = 2.360(3) Å and Cu(1)−O(4) = 2.504(2) Å]. The second bridging oxalato oxygen atom [Cu(1)−O(2) = 2.0747(18) Å] and the N,N,O-type Hfsaaep ligand are located in the basal plane. The distance between the CrIII and CuII ions across the bridging oxalate unit is 5.506 Å. The MnII ion in compound 2 is hexacoordinate (two chelating phen ligands, one oxalato bridging oxygen, and one terminal azido group). The intermolecular CrIII···MnII distance is 5.257 Å. The magnetic properties of the two complexes have been investigated. The magnetic coupling between CrIII and CuII in 1 was found to be ferromagnetic (J = +1.4 cm−1). The nature of the ground state (S = 2) has been further confirmed by plotting the magnetization-versus-field curve. An antiferromagnetic interaction was found between CrIII and MnII in compound 2 (J = −1.9 cm−1). The magnetization-versus-field curve indicates the occurrence of a crossover between the Zeeman components: MS = −1 (ground state S = 1), MS = −2, from the first excited state (S = 2), and MS = −3, from the second excited state. The EPR spectra of the two compounds are discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Co-reporter:Ruxandra Gheorghe, Victor Kravtsov, Yurii A. Simonov, Jean-Pierre Costes, Yves Journaux, Marius Andruh
Inorganica Chimica Acta 2004 Volume 357(Issue 5) pp:1613-1618
Publication Date(Web):25 March 2004
DOI:10.1016/j.ica.2003.11.025
Two new homobinuclear 4f–4f complexes, [LnIII(L)3]2, (Ln=Pr 1; Gd 2) have been synthesized (L−=2,6-diformyl-4-methylphenolato). The crystallographic investigation of 1 reveals centrosymmetric binuclear entities with the metallic centers connected by two of the anionic ligands. The praseodymium ions are bridged by the phenoxo oxygen atoms. One carbonyl group of a bridging molecule is coordinated to one Pr(III) ion, while the other one is coordinated to the second Pr(III) ion. The other four L− ions act as terminal chelated ligands, through the phenoxo oxygen atom and one carbonyl group. The distance between the Pr(III) ions within the binuclear entity is 4.0711(4) Å. The supramolecular solid-state architecture is sustained by a system of π–π interactions. The cryomagnetic study of 2 reveals a very weak antiferromagnetic interaction between the Gd(III) ions (J=−0.053 cm−1, ).Two new homobinuclear lanthanide(III) complexes, [Ln(L)3]2, (Ln=Pr, Gd; L−=2,6-diformyl-4-methylphenolato) have been obtained. The cryomagnetic study of the gadolinium derivative reveals a very weak antiferromagnetic interaction between the Gd(III) ions.
Co-reporter:Augustin M. Madalan, Victor Ch. Kravtsov, Damir Pajic, Kreso Zadro, Yurii A. Simonov, Nicolae Stanica, Lahcène Ouahab, Janusz Lipkowski, Marius Andruh
Inorganica Chimica Acta 2004 Volume 357(Issue 14) pp:4151-4164
Publication Date(Web):15 November 2004
DOI:10.1016/j.ica.2004.06.010
New families of mononuclear and heteropolynuclear complexes have been obtained by using [Cu(AA)(BB)]+ building-blocks (AA=acetylacetonate or salicylaldehydate; BB=1,10-phenanthroline, 4,4′-dimethyl-2,2′-bipyridine). The following mononuclear complexes have been structurally characterized: [Cu(acac)(Me2bipy)]ClO4 (1), [Cu(acac)(Me2bipy)(NCS)] (2), [Cu(acac)(phen)(NCS)] (3). In compound 1 the copper(II) exhibits a square planar geometry, while the stereochemistry of compounds 2 and 3 is square pyramidal, with the isothiocyanato ligand coordinated in the apical position. The reaction between 2 and HgCl2 affords a trinuclear complex, [{Cu(acac)(Me2bipy)(μ-NCS)}2Hg(SCN)2] (4). The reaction between 3 and HgCl2 leads to tetranuclear Cu2Hg2 compound, [{Cu(acac)(phen)(NCS)}2{(ClHg)2(NCS)2}] (5), with a unique structure, and to a trinuclear complex, [{Cu(acac)(phen)(NCS)}2Hg(SCN)2] (6). The structure of 5 consists of a {Hg2(NCS)2} ring on which two [Cu(acac)(phen)(NCS)] moieties are attached. In compounds 4, 5 and 6 the mercury atoms are tetracoordinated. By reacting [Cu(sal)(phen)(OClO3)] with (NEt4)2[Co(NCS)4], a heterohexanuclear compound is obtained: [{Cu(sal)(phen)(SCN)}2Co(NCS)2]2 (7), with the following topology of the metallic centers: Cu–Co–Cu–Cu–Co–Cu. The cobalt(II) ions in 7 are tetracoordinated by nitrogen atoms arising from two bridging and two terminal thiocyanato ligands. The central copper(II) ions are bridged by the phenoxo oxygen atom arising from the sal− ligand. The cryomagnetic properties of compounds 2–5 and 7 have been investigated and discussed. The magnetic behavior of compounds 2–5 has been ascribed to intermolecular exchange interactions mediated by the stacking interactions. The magnetic interaction between Cu(II) and Co(II) in 7 was found ferromagnetic (J=+0.6 cm−1), as theoretically predicted. The exchange interactions between the central copper(II) ions is antiferromagnetic (J=−5.8 cm−1).New families of mononuclear and heteronuclear complexes have been obtained by using [Cu(AA)(BB)]+ building-blocks (AA=acetylacetonate or salicylaldehydate; BB=1,10-phenanthroline, 4,4′-dimethyl-2,2′-bipyridine). The chemistry is based on the addition of different ligands (either simple anions or anionic complexes) to the axial position of copper(II).
Co-reporter:Herbert W Roesky, Marius Andruh
Coordination Chemistry Reviews 2003 Volume 236(1–2) pp:91-119
Publication Date(Web):January 2003
DOI:10.1016/S0010-8545(02)00218-7
Bis-monodentate ligands, such as bis(4-pyridyl) derivatives and bis(4-pyridyl-N-oxide), are able to generate polymetallic coordination networks with interesting supramolecular solid-state architectures. This review is devoted to high-dimensionality systems, which are extended by combining two or three organizing forces: metal-coordination, hydrogen bonds and π–π stacking interactions. A special emphasis is given to the following molecules, which play the role of linkers and spacers in the construction of extended frameworks: 4,4′-bipyridine, 1,2-bis(4-pyridyl)ethane, trans-1,2-bis(4-pyridyl)ethene, trans-4,4′-azo-pyridine, 4,4′-bipyridyl-N,N′-dioxide.
Co-reporter:Ruxandra Gheorghe, Marius Andruh, Jean-Pierre Costes and Bruno Donnadieu
Chemical Communications 2003 (Issue 22) pp:2778-2779
Publication Date(Web):17 Oct 2003
DOI:10.1039/B310082K
A novel heterospin system, [{CuL}Gd(H2O)3{Fe(CN)6}]·4H2O, is obtained by reacting the mononuclear complex, [CuL], with gadolinium(III) nitrate, followed by the substitution of the nitrato groups with [Fe(CN)6]3− ions (L2−
=
N,N′-propylenedi(3-methoxysalicylideneiminato)).
Co-reporter:Augustin M. Madalan;Violeta Voronkova;Ravil Galeev;Ludmila Korobchenko;Jörg Magull;Herbert W. Roesky
European Journal of Inorganic Chemistry 2003 Volume 2003(Issue 10) pp:
Publication Date(Web):13 MAY 2003
DOI:10.1002/ejic.200200619
The reaction between [Mn(MAC)(H2O)2]Cl2·4H2O and LiTCNQ (MAC = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene) affords a complex with the formula [Mn(MAC)(TCNQ)2] (1), whose crystal structure has been determined. Its structure consists of neutral mononuclear entities. The manganese(II) ion is heptacoordinated, with a pentagonal bipyramidal geometry. The apical positions are occupied by the TCNQ·− radicals, while the macrocyclic ligand is coordinated at the equatorial positions. The seven Mn−N distances range from 2.273(3) to 2.301(6) Å. The strong intermolecular π−π stacking interactions between the TCNQ radicals (3.2 Å) leads to weave-like infinite chains, which propagate along the crystallographic c axis. The cryomagnetic investigation of 1 revealed a weak intermolecular antiferromagnetic coupling of the Mn2+ ions (J = −0.18 cm−1), which is mediated by the diamagnetic (TCNQ)22− pairs resulting from the stacking interactions in the crystal. The intermolecular exchange interaction between the Mn2+ ions was further confirmed by variable temperature EPR spectroscopic measurements [|J| = 0.15(5) cm−1], which have been carried out in both the X and Q bands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Co-reporter:Carmen Paraschiv, Marius Andruh, Jean-Pascal Sutter
Inorganica Chimica Acta 2003 Volume 351() pp:385-388
Publication Date(Web):22 July 2003
DOI:10.1016/S0020-1693(03)00208-1
The reaction between trans-[Ni(ampy)2(NO3)2] (ampy=2-aminomethylpyridine) and K3[Cr(CN)6]·2H2O affords a cyano-bridged bimetallic system, [Ni(ampy)2]3[Cr(CN)6]2·6H2O (1), which has been characterized by elemental chemical analysis, FTIR and UV–Vis spectroscopy. According to the UV–Vis spectral data, both Ni(II) and Cr(III) ions are hexacoordinated. The magnetic studies (susceptibility and magnetization measurements) of compound 1 indicate the occurrence of the long-range ferromagnetic order. Compound 1 is a soft magnet with Tc=16 K and a coercive field Hc=170 Oe.The reaction between trans-[Ni(ampy)2(NO3)2] (ampy=2-aminomethylpyridine) and K3[Cr(CN)6]·2H2O affords a cyano-bridged molecule-based magnet, [Ni(ampy)2]3[Cr(CN)6]2·6H2O, with Tc=16 K and a coercive field Hc=170 Oe.
Co-reporter:Floriana Tuna, Gabriel Ionut Pascu, Jean-Pascal Sutter, Marius Andruh, Stéphane Golhen, Joseph Guillevic, Hans Pritzkow
Inorganica Chimica Acta 2003 Volume 342() pp:131-138
Publication Date(Web):10 January 2003
DOI:10.1016/S0020-1693(02)01155-6
Two binuclear complexes of copper(II), [(Hfsaaep)Cu(μ-C2O4)Cu(Hfsaaep)] (1) and [Cu2(Hfsadmpn)2(H2O)2](ClO4)2 (2), have been synthesized by using Schiff-base ligands derived from 3-formyl-salicylic acid: 3-[N-2-(pyridylethyl)formimidoyl]salicylic acid (H2fsaaep) and 3-N-[N′,N′-dimethylaminopropyl)formimidoyl]salicylic acid (H2fsadmpn). The crystal structures of compounds 1 and 2 have been solved. That of compound 1 consists of neutral binuclear entities with copper atoms bridged by one oxalato group, which connect axial–equatorial positions of the two coordination polyhedra. The copper atoms are related by an inversion center and exhibit a distorted square-pyramidal stereochemistry. The Cu⋯Cu distance within the binuclear unit is 5.482(1) Å. The structure of 2 consists of cationic centrosymmetric binuclear entities and perchlorate anions. The tertiary amino groups from the ligands are protonated. The copper(II) ions are bridged by phenolic oxygen atoms, assuming a square-pyramidal geometry bridge the copper(II) ions. The apical positions are occupied by the aqua ligands (CuO=2.335(4) Å). The distance between the copper atoms is 3.008(2) Å. Cryomagnetic investigations of the two compounds reveal antiferromagnetic interactions between the copper ions in both compounds (1: J=−9 cm−1; 2: J=−646 cm−1).Two binuclear copper(II) complexes have been obtained by using Schiff-base ligands derived from 3-formyl-salicylic acid. In compound 1 the copper(II) ions are bridged by an oxalato group, while compound 2 is a phenoxo-bridged dimer. The magnetic properties of the two compounds are discussed.
Co-reporter:Augustin M. Madalan, Herbert W. Roesky, Marius Andruh, Mathias Noltemeyer and Nicolae Stanica
Chemical Communications 2002 (Issue 15) pp:1638-1639
Publication Date(Web):28 Jun 2002
DOI:10.1039/B202628G
A novel heterospin system, [{CuL}2Gd(TCNQ)2]·TCNQ·CH3OH·2CH3CN, is obtained by reacting the mononuclear complex, [CuL], with gadolinium(III) nitrate, followed by the substitution of the nitrato ions with anionic organic radicals.
Co-reporter:Stefania Tanase, Marius Andruh, Achim Müller, Marc Schmidtmann, Corine Mathonière and Guillaume Rombaut
Chemical Communications 2001 (Issue 12) pp:1084-1085
Publication Date(Web):25 May 2001
DOI:10.1039/B101070K
The reaction of
Pr(NO3)3·6H2O with
4,4′-bipyridine N,N′-dioxide (L) and
K3[M(CN)6] [M = FeIII, CoIII]
gives isomorphous heteropolynuclear complexes with formula
[{(H2O)5LPr–NC–M(CN)5
}(μ-L)]·0.5L·4H2O, which exhibit a novel
supramolecular architecture created by the interplay of coordinative,
hydrogen bonding and π–π stacking interactions.
Co-reporter:Gabriela Grasa, Floriana Tuna, Ruxandra Gheorghe, Daniel B. Leznoff, Steven J. Rettig and Marius Andruh
New Journal of Chemistry 2000 vol. 24(Issue 8) pp:615-618
Publication Date(Web):03 Jul 2000
DOI:10.1039/B000655F
A supramolecular heteropolymetallic system, [Cu2(fsal-33)(H2O)2]3[Fe(CN)6]2·8 H2O (1), was obtained by reacting K3[Fe(CN)6] with [Cu2(fsal-33)(H2O)2](ClO4)2 (H2fsal-33 is the symmetric macrocyclic binucleating Schiff base ligand
obtained by condensation of 2,6-diformyl-4-methylphenol with 1,3-propylenediamine). The crystallographic investigation of 1 reveals a complex three-dimensional structure based on hydrogen-bond interactions between the aqua ligands coordinated to the copper atoms, the water molecules, and the cyano groups arising from the hexacyanoferrate(III) anions. The cryomagnetic measurements reveal the strong antiferromagnetic interaction between the copper(II) ions within the binuclear cationic entity, and the temperature dependence of the χMT product, which
is due to the first-order orbital momentum associated with low-spin Fe(III).
Co-reporter:Catalin Anghel, Mihaela Matache, Codruta C. Paraschivescu, Augustin M. Madalan, Marius Andruh
Inorganic Chemistry Communications (February 2017) Volume 76() pp:
Publication Date(Web):February 2017
DOI:10.1016/j.inoche.2016.12.007
•The 2-phenyl-5-(p-tolyl)-1,3,4-oxadiazole acts as a bridging ligand connecting two silver(I) ions.•A 1-D coordination polymer is constructed from binuclear {Ag2L2} nodes and perchlorato spacers.•The new compound shows blue luminescence.The reaction of silver perchlorate with 2-phenyl-5-(p-tolyl)-1,3,4-oxadiazole (L) affords a 1-D coordination polymer, [Ag3L4(ClO4)3] (1). Two silver ions are bridged by two L ligands, through the nitrogen atoms of the oxadiazole ring, resulting in binuclear units. The coordination polymer is constructed from binuclear nodes, {Ag2L2}, connected by perchlorato bridges. The investigation of the optical properties of compound 1 indicates a slight change in the emission profile compared to the organic ligand, showing blue luminescence upon excitation at λ = 300 nm.
Co-reporter:Silviu Nastase, Catalin Maxim, Marius Andruh, Joan Cano, Catalina Ruiz-Pérez, Juan Faus, Francesc Lloret and Miguel Julve
Dalton Transactions 2011 - vol. 40(Issue 18) pp:NaN4908-4908
Publication Date(Web):2011/03/28
DOI:10.1039/C0DT01815E
Three MnIII–MIII (M = Cr and Fe) dinuclear complexes have been obtained by assembling [MnIII(SB)(H2O)]+ and [MIII(AA)(CN)4]− ions, where SB is the dianion of the Schiff-base resulting from the condensation of 3-methoxysalicylaldehyde with ethylenediamine (3-MeOsalen2−) or 1,2-cyclohexanediamine (3-MeOsalcyen2−): [Mn(3-MeOsalen)(H2O)(µ-NC)Cr(bipy)(CN)3]·2H2O (1), [Mn(3-MeOsalen)(H2O)(µ-NC)Cr(ampy)(CN)3][Mn(3-MeOsalen)(H2O)2]ClO4·2H2O (2) and [Mn(3-MeOsalcyen)(H2O)(µ-NC)Fe(bpym)(CN)3]·3H2O (3) (bipy = 2,2′-bipyridine, ampy = 2-aminomethylpyridine and bpym = 2,2′-bipyrimidine). The [M(AA)(CN)4]− unit in 1–3 acts as a monodentate ligand towards the manganese(III) ion through one of its four cyanide groups. The manganese(III) ion in 1–3 exhibits an elongated octahedral stereochemistry with the tetradentate SB building the equatorial plane and a water molecule and a cyanide-nitrogen atom filling the axial positions. Remarkably, the neutral mononuclear complex [Mn(3-MeOsalen)(H2O)2]ClO4 co-crystallizes with the heterobimetallic unit in 2. The values of the MnIII–MIII distance across the bridging cyanide are 5.228 (1), 5.505 (2) and 5.265 Å (3). The packing of the neutral heterobimetallic units in the crystal is governed by the self-complementarity of the [Mn(SB)(H2O)]+ moieties, which interact each other through hydrogen bonds established between the aqua ligand from one fragment with the set of phenolate- and methoxy-oxygens from the adjacent one. The magnetic properties of the three complexes have been investigated in the temperature range 1.9–300 K. Weak antiferromagnetic interactions between the MnIII and MIII ions across the cyanido bridge were found: JMnM = −5.6 (1), −0.63 (2) and −2.4 cm−1 (3) the Hamiltonian being defined as H = −JSMn·SM. Theoretical calculations based on density functional theory (DFT) have been used to substantiate both the nature and magnitude of the exchange interactions observed and also to analyze the dependence of the magnetic coupling on the structural parameters within the MnIII–N–C–MIII motif in 1–3.
Co-reporter:Marius Andruh
Chemical Communications 2011 - vol. 47(Issue 11) pp:NaN3042-3042
Publication Date(Web):2011/01/18
DOI:10.1039/C0CC04506C
The binuclear complexes (3d–3d, 3d–3d′, 3d–4f) with compartmental ligands can efficiently act as tectons in crystal engineering. Various high nuclearity clusters and coordination polymers can be easily obtained by choosing the appropriate spacers. The main interest in such systems arises from their magnetic and photophysical properties. Moreover, 3d–3d′ and 3d–4f complexes are useful precursors in designing heterotrimetallic systems with relevance in molecular magnetism.
Co-reporter:Marius Andruh
Chemical Communications 2007(Issue 25) pp:NaN2577-2577
Publication Date(Web):2007/02/16
DOI:10.1039/B616972D
This article focuses on the employment of bi- and trinuclear complexes as building blocks in designing novel heterometallic systems. A large variety of polynuclear complexes, ranging from high-nuclearity clusters to high-dimensionality coordination polymers, can be constructed by taking advantage of the high flexibility of the multimetallic nodes. The following oligonuclear complexes are currently used as tectons in our laboratory: (a) bis(alkoxo)-bridged copper(II) species; (b) homobinuclear species with metal ions held together by end-off, or macrocyclic compartmental ligands; (c) heterometallic complexes with dissymmetric compartmental ligands. The 3d–4f nodes are particularly interesting since the metal ions interact selectively with various spacers. The intra-node exchange interactions, as well as those between the resulting spins, generate interesting magnetic properties.
Co-reporter:Catalin Maxim, Lorenzo Sorace, Panchanana Khuntia, Augustin M. Madalan, Victor Kravtsov, Alessandro Lascialfari, Andrea Caneschi, Yves Journaux and Marius Andruh
Dalton Transactions 2010 - vol. 39(Issue 20) pp:NaN4847-4847
Publication Date(Web):2010/03/24
DOI:10.1039/B924505G
Three isostructural cyanido-bridged heptanuclear complexes, [{CuII(saldmen)(H2O)}6{MIII(CN)6}](ClO4)3·8H2O (M = FeIII2; CoIII, 3; CrIII4), have been obtained by reacting the dinuclear copper(II) complex, [Cu2(saldmen)2(μ-H2O)(H2O)2](ClO4)2·2H2O 1, with K3[Co(CN)6], K4[Fe(CN)6], and K3[Cr(CN)6], respectively (Hsaldmen is the Schiff base resulting from the condensation of salicylaldehyde with N,N-dimethylethylenediamine). A unique octameric water cluster, with bicyclo[2,2,2]octane-like structure, is sandwiched between the heptanuclear cations in 2, 3 and 4. The cryomagnetic investigations of compounds 2 and 4 reveal ferromagnetic couplings of the central FeIII or CrIII ions with the CuII ions (JCuFe = +0.87 cm−1, JCuCr = +30.4 cm−1). The intramolecular Cu⋯Cu exchange interaction in 3, across the diamagnetic cobalt(III) ion, is −0.3 cm−1. The solid-state 1H-NMR spectra of compounds 2 and 3 have been investigated.
Co-reporter:Andrei A. Patrascu, Sergiu Calancea, Matteo Briganti, Stéphane Soriano, Augustin M. Madalan, Rafael A. Allão Cassaro, Andrea Caneschi, Federico Totti, Maria G. F. Vaz and Marius Andruh
Chemical Communications 2017 - vol. 53(Issue 48) pp:NaN6507-6507
Publication Date(Web):2017/05/23
DOI:10.1039/C7CC03236F
End-off bicompartmental ligands bearing a nitronyl–nitroxide arm have been designed for synthesizing various heterospin molecular systems. These ligands can selectively interact with 3d and 4f metal ions, leading to 2p–4f, 2p–3d, and 2p–3d–4f complexes. The magnetic properties of the 2p–4f and 2p–3d–4f complexes have been investigated and rationalized by theoretical calculations.
Co-reporter:Traian D. Pasatoiu, Mael Etienne, Augustin M. Madalan, Marius Andruh and Roberta Sessoli
Dalton Transactions 2010 - vol. 39(Issue 20) pp:NaN4808-4808
Publication Date(Web):2010/02/24
DOI:10.1039/B925425K
A tetranuclear complex and a 1-D coordination polymer with a ladder-like topology have been obtained by connecting [NiIIDyIII] nodes with dicarboxylato ligands: [Ni2(valpn)2Dy2III(pdca)2(NO3)(H2O)6](NO3)·4H2O 1, and ∞1[Ni2(H2O)2(valpn)2Dy2(tfa)3]·4CH3CN 2 (valpn2− = the dianion of the Schiff base resulting from reacting o-vanillin with 1,3-propanediamine; pdca2− = the dianion of 2,6-pyridinedicarboxylic acid; tfa2− = the dianion of the terephthalic acid). The magnetic measurements show a ferromagnetic interaction between NiII and DyIII, and that both compounds behave like SMM with strong tunnelling. The barrier of 2 (17.4 K) is higher than that of 1 (13.6 K).
Co-reporter:Diana Visinescu, Maria-Gabriela Alexandru, Augustin M. Madalan, Ie-Rang Jeon, Corine Mathonière, Rodolphe Clérac and Marius Andruh
Dalton Transactions 2016 - vol. 45(Issue 18) pp:NaN7649-7649
Publication Date(Web):2016/03/15
DOI:10.1039/C6DT00614K
Four isostructural trinuclear 3d–4f–4(5)d heterotrimetallic complexes, with the general formula [L2CuLn(H2O)5(μ-NC)M(CN)7], were obtained from the association of binuclear 3d–4f complexes and {MV(CN)8}3− metalloligands (M = Mo, Ln = La 1; M = W, Ln = La 2; M = Mo, Ln = Gd 3; M = Mo; Ln = Tb 4, where H2L2 = 1,2-ethanediylbis(2-iminomethylene-6-methoxy-phenol)). The metalloligand coordinates through a single-cyanido group at the apical position of the copper(II) ion belonging to the {CuIILnIII} binuclear complex. The analysis of the magnetic data for the La(III) derivatives (compounds 1 and 2), in the 1.85–300 K temperature range, shows a weak ferromagnetic exchange interaction between CuII and MoV/WV ions across the cyanido bridge (JCuM/kB = 3.6(6) K; g = 2.23(5) for 1 and JCuM/kB = 3.8(6) K, g = 2.21(5) for 2, with H = −2JCuMSCu·SM). These results were used to simulate the magnetic properties of compound 3, using the isotropic spin Hamiltonian H = −2JCuMoSCu·SMo − 2JCuGdSCu·SGd. The resulting magnetic interaction between CuII and GdIII ions via the phenoxo-bridge was found to be weakly ferromagnetic (JCuGd/kB = +4.5(2) K with JCuMo/kB = +3.6(2) K, gGd = gCu = 2.00 and gMo = 1.98). The dc magnetic properties for compound 4 also show a predominant ferromagnetic interaction, while the ac magnetic measurements indicate the presence of the slow relaxation of the magnetization below 3.5 K.
Co-reporter:Catalin Maxim, Corine Mathonière and Marius Andruh
Dalton Transactions 2009(Issue 37) pp:NaN7810-7810
Publication Date(Web):2009/07/31
DOI:10.1039/B905621A
A pentanuclear complex, [Mo(CN)8{CuL1}2{CuL1(H2O)}2]·6H2O 1, and a decanuclear one, [Mo(CN)8{CuL2}3{CuL2(H2O)}]2·10H2O 2, have been obtained following the building-block approach (HL1 and HL2 are tridentate Schiff bases obtained by reacting salicylaldehyde with 2-aminomethyl-pyridine and 2-aminoethyl-pyridine, respectively). Both compounds present reversible photo-induced magnetic properties interpreted as a MoIV–CuII charge transfer. Compound 2 exhibits a lower efficiency of this metal–metal charge transfer than compound 1 attributed to a less flexible structure of 2 compared to 1.
Co-reporter:Traian D. Pasatoiu, Augustin M. Madalan, Marian Zamfirescu, Carmen Tiseanu and Marius Andruh
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 32) pp:NaN11456-11456
Publication Date(Web):2012/06/13
DOI:10.1039/C2CP41026E
Heterobimetallic [ZnIILnIII] complexes have been obtained using a compartmental Schiff-base ligand, H2valdmpn, resulting from the 2:1 condensation between o-vanillin and 2,2-dimethyl-propilenediamine: [Zn(H2O)(valdmpn)Sm(O2NO)3] 1, [Zn(H2O)(valdmpn)Tb(O2NO)3] 2a, [Zn(H2O)(valdmpn)Tb(O2NO)3]·H2O 2b, and [Zn(H2O)(valdmpn)Gd(O2NO)3]·H2O 3. The crystal structures of 1, 2b, and 3 have been solved. Compounds 1 and 2a crystallize in a non-centrosymmetric space group (P212121), being isomorphous. Crystals 2b and 3 are also isomorphous (space group P). The complex entities in the four crystals are similar and their structures consist of binuclear species with the pentacoordinated zinc(II) ion hosted into the N2O2 compartment and the lanthanide(III) ion in the large, open compartment, with a coordination number of 10. The photophysical properties of the four compounds have been investigated. Strong visible excited (excitation tails extend up to 420–430 nm) one photon antenna sensitization was obtained with the samarium(III) and terbium(III) derivatives. Following femtosecond Ti:Sapphire laser at λex = 775 nm, both second-harmonic generation at λem = 775/2 nm and two-photon induced emission in the VIS range were obtained, extending thus the excitation range of these complexes from the VIS to the NIR spectral range. The two-photon induced emission and second harmonic generation effect for a samarium(III) complex are reported for the first time.
Co-reporter:Traian D. Pasatoiu, Alberto Ghirri, Augustin M. Madalan, Marco Affronte and Marius Andruh
Dalton Transactions 2014 - vol. 43(Issue 24) pp:NaN9142-9142
Publication Date(Web):2014/03/20
DOI:10.1039/C4DT00515E
Two original heterooctanuclear [NiII4LnIII4] complexes (LnIII = SmIII, GdIII) have been obtained starting from the [NiII(valpn)(H2O)2] mononuclear precursor [H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)] and the corresponding lanthanide nitrates, in the presence of azide anions, through slow capture of atmospheric CO2. Three weak and competitive exchange interactions, JGdGd, JGdNi, JNiNi, make the ground state of this magnetic system degenerate at cryogenic temperature and zero field. This, along with the high spin of GdIII, lead to a significant magnetocaloric effect spread in the temperature range 1 to 20 K (ΔSm[0–7 T, 3.5 K] = 19 J kg−1 K−1).
Co-reporter:Alina S. Dinca, Sergiu Shova, Adrian E. Ion, Catalin Maxim, Francesc Lloret, Miguel Julve and Marius Andruh
Dalton Transactions 2015 - vol. 44(Issue 16) pp:NaN7151-7151
Publication Date(Web):2015/03/20
DOI:10.1039/C5DT00778J
Two types of oxalato-bridged heterometallic 3d–4f dodeca- and hexanuclear compounds have been obtained by connecting six bi- and, respectively, trinuclear moieties through oxalato bridges arising from the slow decomposition of the L-ascorbic acid.
Co-reporter:Ruxandra Gheorghe, Augustin M. Madalan, Jean-Pierre Costes, Wolfgang Wernsdorfer and Marius Andruh
Dalton Transactions 2010 - vol. 39(Issue 20) pp:NaN4736-4736
Publication Date(Web):2010/01/26
DOI:10.1039/B925636A
By connecting [LCuTb]3+ nodes with [Fe(CN)6]3− spacers a 1-D coordination polymer with slow relaxation of magnetization is obtained (L2− is the N,N′-propylene-bis(3-methoxysalicylideneiminato) anion).
Co-reporter:Diana Visinescu, Ie-Rang Jeon, Augustin M. Madalan, Maria-Gabriela Alexandru, Bogdan Jurca, Corine Mathonière, Rodolphe Clérac and Marius Andruh
Dalton Transactions 2012 - vol. 41(Issue 44) pp:NaN13581-13581
Publication Date(Web):2012/10/03
DOI:10.1039/C2DT32081A
The reaction of [Cu(valen)] with Tb(NO3)3 and (Bu3NH)3[W(CN)8] affords two types of crystals: [{W(CN)8}Cu(valen)Tb(OH2)5]·2H2O (1, a discrete trinuclear complex) and [{W(CN)8}Cu(valen)Tb(OH2)4]·CH3CN·H2O (2, an infinite zig-zag chain), both compounds showing slow relaxation of the magnetization (H2valen is the Schiff base resulting from the reaction of o-vanillin with 1,2-ethanediamine).
Co-reporter:Diana Visinescu, Maria-Gabriela Alexandru, Augustin M. Madalan, Céline Pichon, Carine Duhayon, Jean-Pascal Sutter and Marius Andruh
Dalton Transactions 2015 - vol. 44(Issue 38) pp:NaN16727-16727
Publication Date(Web):2015/07/06
DOI:10.1039/C5DT01738F
Three families of heterotrimetallic chains (type 1–type 3), with different topologies, have been obtained by reacting the 3d–4f complexes, [{Cu(L1)}xLn(NO3)3] with x = 1 or 2, formed in situ by the reaction of Schiff-base bi-compartmental [CuII(L1)] complexes and lanthanide(III) salts, with (NHBu3)3[M(CN)8] (M = MoV, WV). For type 1 series of compounds, 1-D coordination polymers, with the general formula [{Cu2(valpn)2Ln}{M(CN)8}]·nH2O·mCH3CN (where H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol), result from the association of trinuclear {CuII2LnIII} moieties and [MV(CN)8]3− anions acting as tri-connecting spacers [Ln = La (1), Ce (2), Eu (3), Tb (4), Ho (5), M = Mo; Ln = Tb (6), Ho (7), M = W; m = 0, n = 1.5 (7) and 2 (1–4, 6); n = 1, m = 1 (5)]. The type 2 family has the general formula [{Cu(valdp)Ln(H2O)4}{M(CN)8}]·2H2O·CH3CN (where H2valdp = 1,2-propanediylbis(2-iminomethylene-6-methoxy-phenol)) and also consists of heterotrimetallic chains involving binuclear {CuIILnIII} units linked to [M(CN)8]3− anions coordinating through two cyano groups [Ln = Gd (8), Tb (9), Dy (10); M = Mo; Ln = La (11), Gd (12), Tb (13), Dy (14); M = W]. With large LnIII ions (LaIII and PrIII), the type 3 family of heterotrimetallic compounds are assembled: [{Cu2(valdp)2Ln(H2O)4}{Mo(CN)8}]·nCH3OH·mCH3CN, n, m = 0, Ln = La (15); n = m = 1, Pr (16), in which the trinuclear {CuII2LnIII} nodes are connected to [MoV(CN)8]3− anions that act as tetra-connecting spacers. For TbIII derivatives of the type 1 (compounds 4 and 6), the DC magnetic properties indicate a predominant ferromagnetic CuII–TbIII interaction, while the AC magnetic susceptibility (in the presence of a static magnetic field, HDC = 3000 Oe) emphasize the slow relaxation of the magnetization (Ueff/kB = 20.55 K and τ0 = 5.5 × 10−7 s for compound 4, Ueff/kBT = 15.1 K and τ0 = 1.5 × 10−7 s for compound 6). A predominant ferromagnetic CuII–LnIII interaction was also observed in the type 2 series (compounds 8–10 and 12–14) as a result of the magnetic coupling between copper(II) and lanthanide(III) ions via the phenoxo-bridge. The magnetic behavior for the LaIII derivatives reveals that weak ferromagnetic interactions are also operative between the CuII and the 4d/5d centers.
![Phenol, 2,2'-[1,3-propanediylbis(nitrilomethylidyne)]bis[6-methoxy-](/data/chemimg/89800/5767-53-3.png)
![Phenol, 2,2'-[1,3-propanediylbis(nitrilomethylidyne)]bis[6-methoxy-](/data/chemimg/89800/5767-53-3_b.png)