The use of (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) ligand, H3L, in Ni/Ln chemistry has led to the isolation of three new isostructural [NiII6LnIII3] metallic cages. More specifically, the reaction of Ni(ClO4)2·6H2O, the corresponding lanthanide nitrate salt, and H3L in MeCN, under solvothermal conditions in the presence of NEt3, led to the isolation of three complexes with the formulas [Ni6Gd3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (1·5.75MeCN·2Et2O·1.5H2O), [Ni6Dy3(OH)6(HL)6(NO3)3]·2MeCN·2.7Et2O·2.4H2O (2·2MeCN·2.7Et2O·2.4H2O), and [Ni6Er3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (3·5.75MeCN·2Et2O·1.5H2O). The structure of all three clusters describes a [LnIII3] triangle capping a [NiII6] trigonal prism. Direct current magnetic susceptibility studies in the 5–300 K range for complexes 1–3 reveal the different nature of the magnetic interactions within the clusters: dominant antiferromagnetic exchange interactions for the DyIII and ErIII analogues and dominant ferromagnetic interactions for the GdIII example. Alternating current magnetic susceptibility measurements under zero external dc field displayed fully formed temperature- and frequency-dependent out-of-phase peaks for the [NiII6DyIII3] analogue, establishing its single molecule magnetism behavior with Ueff = 24 K.

The use of N-salicylidene-o-aminophenol (H2saph) in 4f-metal chemistry has led to the isolation of seven new isostructural lanthanide(III) [LnIII] complexes. More specifically the Ln(NO3)3·xH2O/H2saph/Et3N (1:1:1) reaction mixtures in DMF/MeCN gave complexes [Ln2(NO3)2(saph)2(DMF)4] (Ln = Sm (1); Eu (2); Gd (3); Tb (4); Dy (5); Ho (6); Er (7)) in good yields (∼65%). The structures of the isomorphous complexes 3 and 5 were solved by single-crystal X-ray crystallography; the other complexes are proposed to be isostructural with 3 and 5 based on elemental analyses, IR spectra and powder XRD patterns. The two LnIII atoms in the centrosymmetric molecules of 3 and 5 are doubly bridged by the deprotonated iminophenolato oxygen atoms of two nearly planar η1:η1:η2:μ saph2− ligands. The imino nitrogen and five terminal oxygen atoms (the salicylaldiminate, two from one bidentate chelating nitrato group and two from two DMF ligands) complete square antiprismatic coordination at each metal centre. The IR spectra of the complexes are discussed in terms of the coordination modes of the ligands present in the complexes. Solid-state emission studies for all 1–7 display identical ligand-based photoluminescence. Dc magnetic susceptibility studies in the 2–300 K range reveal the presence of a weak, intramolecular antiferromagnetic exchange interaction (J = −0.19(1) cm−1 based on the spin Hamiltonian H = −J(ŜGd·ŜGd′)) for 3 and probably ferromagnetic exchange interaction within the molecules of 4 and 5. Ac magnetic susceptibility measurements in zero dc field show temperature- and frequency-dependent out-of-phase signals with two well defined, thermally-activated processes for 5, suggesting potential single-molecule magnetism character. The Ueff value is 17.4 cm−1 for the higher temperature process and 16.2 cm−1 for the lower temperature one. The combination of photoluminescence and single-molecule behaviour in the DyIII2 complex 5 is critically discussed.

Employment of H3L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal manganese-lanthanide cluster chemistry has led to the isolation of five new octametallic heteronuclear isostructural [MnIII6LnIII2] complexes. More specifically, the reaction of Mn(ClO4)2·6H2O with H3L and the corresponding lanthanide nitrate in MeCN in the presence of a base, NEt3, yielded four complexes with the general formula [MnIII6LnIII2O2(OH)2(H2O)2(HL)6(NO3)6]·6MeCN·0.5H2O (Ln: Gd, 1·6MeCN·0.5H2O; Tb, 2·6MeCN·0.5H2O; Dy, 3·6MeCN·0.5H2O; Er, 4·6MeCN·0.5H2O). Furthermore, the YIII analogue, [MnIII6YIII2O2(OH)2(H2O)2(HL)6(NO3)6]·6MeCN·0.5H2O (5·6MeCN·0.5H2O), was also synthesized in the same manner. All five clusters describe a central rod-like topology consisting of four face-sharing defective cubane metallic units, forming a planar hexametallic [MnIII4LnIII2] core, which is further capped by two MnIII ions. Dc magnetic susceptibility studies in the 5–300 K range for complexes 1–5 reveal the presence of dominant antiferromagnetic exchange interactions within the metallic clusters, while ac magnetic susceptibility measurements show temperature and frequency dependent out-of-phase signals for the DyIII analogue (3·6MeCN·0.5H2O), suggesting potential single molecule magnetism character. Furthermore, the YIII analogue yielded a diamagnetic ground-state for the [MnIII6] core, thus proving that the SMM character displayed by 3·6MeCN·0.5H2O is due to the presence of the DyIII centres.

The use of H3L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal manganese–lanthanide carboxylate cluster chemistry has led to the isolation of two new dodecametallic heteronuclear isostructural [MnIII6LnIII6] complexes (Ln = Gd, Dy), with the Dy analogue displaying temperature and frequency dependent out-of-phase signals suggesting possible single molecule magnetism behaviour.

Employment of H3L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal copper-lanthanide cluster chemistry has led to the isolation of four new enneanuclear heteronuclear isostructural [CuII7LnIII2] complexes. More specifically, the solvothermal reaction of Cu2(OAc)4·2H2O with H3L and the corresponding lanthanide nitrate salt in MeCN in the presence of a base, NEt3, yielded three complexes with the general formula [CuII7LnIII2(L)4(HL)2(OAc)4]·2MeCN (Ln: Gd, 1·2MeCN; Tb, 2·2MeCN; Dy, 3·2MeCN), while in addition the YIII analogue, [CuII7YIII2(L)4(HL)2(OAc)4]·2MeCN (4·2MeCN), was also synthesized in the same manner. The structure of the cluster describes two corner-sharing [Cu3Ln] cubane metallic units, each one further connected to one CuII ion. Dc magnetic susceptibility studies in the 5–300 K range for complexes 1–4 reveal the presence of both ferromagnetic and antiferromagnetic exchange interactions within the metallic clusters.

The use of LH3 (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) and aibH (2-amino-isobutyric acid) in 4f chemistry has led to the isolation of eight new isostructural lanthanide complexes. More specifically, the reaction of the corresponding lanthanide nitrate salt with LH3 and aibH in MeOH, under solvothermal conditions in the presence of NEt3, led to the isolation and characterization of seven complexes with the general formulae [LnIII7(OH)2(L′)9(aib)]·4MeOH (Ln = Gd, 1·4MeOH; Tb, 2·4MeOH; Dy, 3·4MeOH; Ho, 4·4MeOH; Er, 5·4MeOH; Tm, 6·4MeOH; Yb, 7·4MeOH L′ = the dianion of the Schiff base between naphthalene aldehyde and 2-amino-isobutyric acid). Furthermore, the isostructural YIII analogue, cluster [YIII7(OH)2(L′)9(aib)]·4MeOH (8·4MeOH), was synthesized in a similar manner to 1–7. The structure of all eight clusters describes a distorted [MIII6] octahedron which encapsulates a seventh MIII ion in an off-centre fashion. Dc magnetic susceptibility studies in the 5–300 K range for complexes 1–7 reveal the presence of dominant antiferromagnetic exchange interactions within the metallic clusters as evidenced by the negative Weiss constant, θ, while ac magnetic susceptibility measurements show temperature and frequency dependent out-of-phase signals for the [DyIII7] analogue (3·4MeOH), suggesting potential single molecule magnetism character. Furthermore, for complex 1, simulation of its dc magnetic susceptibility data yielded very weak antiferromagnetic interactions within the metallic centres. Solid-state emission studies for all 1–8 clusters display ligand-based emission, while extended 1D and 2D NMR studies for 8·4MeOH reveal that the species retain their structural integrity in solution. In addition, TGA measurements for 1, 3 and 7 revealed excellent thermal stability up to 340 °C for the clusters.

The reaction of Co(OAc)2·4H2O with LH (LH = 11H-indeno[1,2-b]quinoxalin-11-one oxime) in MeOH in the presence of NEt3 forms the complex [CoIII2CoIIO(OAc)3L3]·0.5MeOH·0.2H2O (1·0.5MeOH·0.2H2O), while repeating the reaction under solvothermal conditions yielded the heptanuclear cluster [CoII7L9 (OH)2(OAc)2.7(MeO)0.3(H2O)]·4.6MeOH·3.3H2O (2·4.6MeOH·3.3H2O). Changing the starting metal salt to Co(ClO4)2·6H2O and upon the reaction with LH in the presence of NEt3 under high temperature and pressure, we managed to isolate the decanuclear cluster [CoII10L14(OH)3.6(MeO)0.4](ClO4)2·8.5MeOH·5.75H2O (3·8.5MeOH·5.75H2O), while under normal bench conditions and upon employment of pivalates in the reaction mixture complex [CoII4L4(piv)4(MeOH)2]·MeOH·H2O (4·MeOH·H2O) was formed. Furthermore, the reaction of Co(ClO4)2·6H2O with LH and aibH (2-amino-isobutyric acid) in the presence of NEt3 in MeOH gave the mononuclear complex [CoIIIL(aib)2]·3H2O (5·3H2O), while upon increasing the metal–ligand ratio cluster [CoIII2CoIIL4(aib)2(OH)2]·7.9MeOH (6·7.9MeOH) was isolated. Finally, repeating the reaction that yielded the mononuclear complex 5·3H2O under solvothermal conditions, gave the octanuclear cluster [CoII8L10(aib)2(MeO)2](ClO4)2·6.8MeOH·7H2O (7·6.8MeOH·7H2O). Variable temperature dc magnetic susceptibility studies for complexes 2, 3, 4 and 7, reveal that all clusters display dominant antiferromagnetic interactions leading to small or diamagnetic ground-states, S.

The reaction of Ni(OAc)2·4H2O with LH (LH = 11H-indeno[1,2-b]quinoxalin-11-one oxime) in a mixture of solvents comprising MeCN/MeOH (1:1) under solvothermal conditions in the presence of NEt3 forms the complex [Ni3(L)5(OAc)(MeOH)]·2.6MeCN·0.7MeOH·0.2H2O (1·2.6MeCN·0.7MeOH·0.2H2O) in moderate yield. Repeating the reaction in MeOH produces the complex [Ni6(L)6(OAc)4(OMe)2]·1.5MeOH·1.3H2O (2·1.5MeOH·1.3H2O) in good yield, while the reaction between Ni(ClO4)2·6H2O and LH in the presence of NEt3 in MeOH under solvothermal conditions yields complex [Ni5(L)6(OMe)2(OH)(H2O)2(MeOH)2](ClO4)·8.8MeOH·1.4H2O (3·8.8MeOH·1.4H2O). Furthermore, the reaction between Ni(ClO4)2·6H2O, LH and 2-amino-isobutyric acid, aibH, in MeCN in the presence of NEt3 forms complex [Ni7(L)7(aib)4(OH)(MeCN)0.5(H2O)0.5](ClO4)2·4MeCN·0.25H2O (4·4MeCN·0.25H2O) under high temperature/pressure, while the same reaction in MeOH yields complex [Ni8(L)8(aib)3(OMe)3](ClO4)2·0.75MeOH·4.2H2O (5·0.75MeOH·4.2H2O). Variable temperature dc magnetic susceptibility studies show that all 1–5 clusters display a small or a diamagnetic ground-state, S.

The reaction of MnBr2·4H2O with 2-(hydroxymethyl)-2-((3-hydroxynaphthalen-2-yl)methyleneamino)propane-1,3-diol (LH4) in MeOH, afforded the complex [MnIV(LH2)2]·MeOH (1·MeOH) in very good yield. Repeating the same reaction and replacing MnBr2 4H2O with Mn(OAc)2·4H2O gave the complex [MnIII2MnII(LH2)2(OAc)4(MeOH)2]·4MeOH (2·4MeOH) in good yield. Finally, the reaction of Mn(OAc)2·4H2O, with LH4 and PhCOONa in the presence of NEt3 in MeOH, afforded the complex [MnIII2MnII(LH2)2(OAc)2(O2CPh)2(MeOH)2]·MeOH (3·MeOH) in moderate yield. The crystal structures of 1–3 have been determined by single-crystal X-ray crystallography. Complex 1 is a mononuclear MnIV complex, in which the metal ion is found in a trans-O4N2 octahedral environment. Complex 2 is a mixed-valent linear [MnIII2MnII] cluster in which the central MnII ion is connected via carboxylates and monoatomic bridges from the tetraol ligands to the two terminal MnIII ions, while cluster 3 can be regarded as the “incomplete” benzoate analogue of complex 2. DC magnetic susceptibility studies were performed on a polycrystalline samples of 2 and 3, revealing the presence of antiferromagnetic interactions within the clusters leading to an S = 1/2 ground-state for both complexes.Graphical abstractEmployment of 2-(hydroxymethyl)-2-((3-hydroxynaphthalen-2-yl)methyleneamino) propane-1,3-diol in manganese cluster chemistry afforded three complexes: Complex 1 is a mononuclear MnIV complex, while 2 and 3 are linear [MnIIIMnIIMnIII] clusters.Highlights► Linear clusters. ► Mixed-valent manganese clusters. ► Long intramolecular magnetic interaction.

The synthesis and magnetic properties of 13 new homo- and heterometallic Co(II) complexes containing the artificial amino acid 2-amino-isobutyric acid, aibH, are reported: [CoII4(aib)3(aibH)3(NO3)](NO3)4·2.8CH3OH·0.2H2O (1·2.8CH3OH·0.2H2O), {Na2[CoII2(aib)2(N3)4(CH3OH)4]}n (2), [CoII6LaIII(aib)6(OH)3(NO3)2(H2O)4(CH3CN)2]·0.5[La(NO3)6]·0.75(ClO4)·1.75(NO3)·3.2CH3CN·5.9H2O (3·3.2CH3CN·5.9H2O), [CoII6PrIII(aib)6(OH)3(NO3)3(CH3CN)6]·[Pr(NO3)5]·0.41[Pr(NO3)3(ClO4)0.5(H2O)1.5]·0.59[Co(NO3)3(H2O)]·0.2(ClO4)·0.25H2O (4·0.25H2O), [CoII6NdIII(aib)6(OH)3(NO3)2.8(CH3OH)4.7(H2O)1.5]·2.7(ClO4)·0.5(NO3)·2.26CH3OH·0.24H2O (5·2.26CH3OH·0.24H2O), [CoII6SmIII(aib)6(OH)3(NO3)3(CH3CN)6]·[Sm(NO3)5]·0.44[Sm(NO3)3(ClO4)0.5(H2O)1.5]·0.56[Co(NO3)3(H2O)]·0.22(ClO4)·0.3H2O (6·0.3H2O), [CoII6EuIII(aib)6(OH)3(NO3)3(CH3OH)4.87(H2O)1.13](ClO4)2.5(NO3)0.5·2.43CH3OH·0.92H2O (7·2.43CH3OH·0.92H2O), [CoII6GdIII(aib)6(OH)3(NO3)2.9(CH3OH)4.9(H2O)1.2]·2.6(ClO4)·0.5(NO3)·2.58CH3OH·0.47H2O (8·2.58CH3OH·0.47H2O), [CoII6TbIII(aib)6(OH)3(NO3)3(CH3CN)6]·[Tb(NO3)5]·0.034[Tb(NO3)3(ClO4)0.5(H2O)0.5]·0.656[Co(NO3)3(H2O)]·0.343(ClO4)·0.3H2O (9·0.3H2O), [CoII6DyIII(aib)6(OH)3(NO3)2.9(CH3OH)4.92(H2O)1.18](ClO4)2.6(NO3)0.5·2.5CH3OH·0.5H2O (10·2.5CH3OH·0.5H2O), [CoII6HoIII(aib)6(OH)3(NO3)3(CH3CN)6]·0.27[Ho(NO3)3(ClO4)0.35(H2O)0.15]·0.656[Co(NO3)3(H2O)]·0.171(ClO4) (11), [CoII6ErIII(aib)6(OH)4(NO3)2(CH3CN)2.5(H2O)3.5](ClO4)3·CH3CN·0.75H2O (12·CH3CN·0.75H2O), and [CoII6TmIII(aib)6(OH)3(NO3)3(H2O)6]·1.48(ClO4)·1.52(NO3)·3H2O (13·3H2O). Complex 1 describes a distorted tetrahedral metallic cluster, while complex 2 can be considered to be a 2-D coordination polymer. Complexes 3–13 can all be regarded as metallo-cryptand encapsulated lanthanides in which the central lanthanide ion is captivated within a [CoII6] trigonal prism. dc and ac magnetic susceptibility studies have been carried out in the 2–300 K range for complexes 1, 3, 5, 7, 8, 10, 12, and 13, revealing the possibility of single molecule magnetism behavior for complex 10.

Employment of the artificial amino acid 2-amino-isobutyric acid, aibH, in CuII and CuII/LnIII chemistry led to the isolation and characterization of 12 new heterometallic heptanuclear [Cu6Ln(aib)6(OH)3(OAc)3(NO3)3] complexes consisting of trivalent lanthanide centers within a hexanuclear copper trigonal prism (aibH = 2-amino-butyric acid; Ln = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), and Yb (12)). Direct curent magnetic susceptibility studies have been carried out in the 5–300 K range for all complexes, revealing the different nature of the magnetic interactions between the 3d–4f metallic pairs: dominant antiferromagnetic interactions for the majority of the pairs and dominant ferromagnetic interactions for when the lanthanide center is GdIII and DyIII. Furthermore, alternating current magnetic susceptibility studies reveal the possibility of single-molecule magnetism behavior for complexes 7 and 8. Finally, complexes 2, 5–8, 10, and 12 were analyzed using positive ion electrospray mass spectrometry (ES-MS), establishing the structural integrity of the heterometallic heptanuclear cage structure in acetonitrile.

The employment of 2-(β-naphthalideneamino)-2-(hydroxymethyl)-1-propanol and 2-aminoisobutyric acid in dysprosium chemistry has led to the isolation of a novel heptanuclear [DyIII7] cluster displaying single-molecule-magnetism behavior and blue-emitting properties.

The employment of 2-(β-naphthalideneamino)-2-(hydroxymethyl)-1-propanol (LH3) in cobalt, nickel, and copper chemistry has led to the isolation of five new metallic complexes with interesting magnetic properties. More specifically, the reaction of Co(OAc)2·4H2O with LH3 in MeOH in the presence of NEt3 under solvothermal conditions forms the complex [CoIII2CoII3(L)2(LH)2(L′)(OAc)]·8.5MeOH (1·8.5MeOH; L′ = monoanion of 2-hydroxy-1-naphthaldehyde), while in nickel chemistry, a similar reaction of Ni(OAc)2·6H2O with LH3 in MeCN in the presence of NEt3 under high pressure/temperature forms the complex [NiII(LH2)2]·2MeCN (2·2MeCN). Repeating the same reaction in MeOH and switching from Ni(OAc)2·4H2O to NiSO4·4H2O produces the complex [NiII4(HL)3(OMe)(MeOH)3](SO4)0.5·2MeOH (3·2MeOH) under solvothermal conditions. Furthermore, in copper chemistry, the reaction of Cu2(OAc)4·2H2O with LH3 in the presence of NEt3 in MeOH under solvothermal conditions affords the complex [CuII4(LH)4] (4), while the same reaction under ambient temperature and pressure conditions forms [CuII4(LH)4] ·3.5MeOH·2.25H2O (5·3.5MeOH·2.25H2O). Complex 1 is a mixed-valent [CoIII2CoII3] complex, consisting of three edge-sharing [Co3] triangles. Complex 2 is a nickel(II) monomer in which the central metal is found in an octahedral geometry, while complex 3 describes a [NiII4] cubane. Complexes 4 and 5 may be considered as structural isomers because they possess the same formulas but different topologies: 4 describes a highly distorted [CuII4(OR)4]4+ eight-membered ring, while 5 consists of a distorted [CuII4(μ3-OR)4]4+ cubane. In addition, 5 can be converted to 4 in excellent yield under solvothermal conditions. Direct-current magnetic susceptibility studies have been carried out in the 5–300 K range for complexes 1 and 3–5, revealing the possibility of a high-spin ground state for 1, an S = 4 ground state for 2, and diamagnetic ground states for 4 and 5.

The synthesis and magnetic properties of five new homo- and heterometallic nickel(II) complexes containing artificial amino acids are reported: [Ni4(aib)3(aibH)3(NO3)](NO3)4·3.05MeOH (1·3.05MeOH), [Ni6La(aib)12](NO3)3·5.5H2O (2·5.5H2O), [Ni6Pr(aib)12](NO3)3·5.5H2O (3·5.5H2O), [Ni5(OH)2(l-aba)4(OAc)4]·0.4EtOH·0.3H2O 6(4·0.4EtOH·0.3H2O), and [Ni6La(l-aba)12][La2(NO3)9] (5; aibH = 2-aminoisobutyric acid; l-abaH = l-2-aminobutyric acid). Complexes 1 and 4 describe trigonal-pyramidal and square-based pyramidal metallic clusters, respectively, while complexes 2, 3, and 5 can be considered to be metallocryptand-encapsulated lanthanides. Complexes 4 and 5 are chiral and crystallize in the space groups I222 and P213, respectively. Direct-current magnetic susceptibility studies in the 2–300 K range for all complexes reveal the presence of dominant antiferromagnetic exchange interactions, leading to small or diamagnetic ground states.

The use of 2-amino-isobutyric acid in Co/Ln chemistry has led to the isolation of two unique [CoII6LnIII] 3d-4f metallic cages in which the LnIII centre (Ln = Eu, Dy) is encapsulated within a CoII6 trigonal prism.

The use of phamidoxH2 (phamidoxH2 = 2-dihydroxy-2-phenylacetamidine) in manganese cluster chemistry led to the synthesis and characterization of a hexametallic and an octametallic MnIII cluster, both of which display a S = 3 ground state.

The reaction of Mn(ClO4)2·6H2O with Ph-saoH2 (Ph-saoH2 = 2-hydroxybenzophenone oxime) in MeCN in the presence of sodium propionate forms the complex [MnIII6O2(Ph-sao)6(prop)2(MeCN)2]·5.27MeCN (1·5.27MeCN) (prop = propionate). Repeating the same reaction in EtOH produces the complex [MnIII6O2(Ph-sao)6(prop)2(EtOH)4] (2). Complexes 1 and 2 may be considered as structural isomers, since they display the same metallic core but different coordination modes of the propionate ligands; bridging in 1 and terminal in 2. Performing similar reactions and switching from sodium propionate to sodium adamantane-carboxylate (NaO2C-ada) and sodium pivalate (Napiv) in the presence of NEt4OH yields the complexes [MnIII6O2(Ph-sao)6(O2C-ada)2(MeOH)4] (3) and [MnIII6O2(Ph-sao)6(piv)2(EtOH)4]·0.5Et2O (4·0.5Et2O), respectively. All four complexes contain the same {MnIII3O(Ph-sao)3} building block. Variable temperature magnetic susceptibility and magnetization studies show that all complexes possess an S = 4 ground-state.

The reaction of Mn(ClO4)2·6H2O with Ca(prop)2 and Me-saOH2 in MeCN yields the heterometallic polymeric complex {[MnIII6Ca2O2(Me-saO)6(prop)6 (H2O)2].2MeCN.0.95H2O}n (1) (prop = propionate; Me-saOH2 = 2-hydroxyphenylethanone oxime). Complex 1 consists of hexanuclear centrosymmetric [MnIII6O2(Me-saO)6]2+ units bridged by propionate calcium [Ca2(prop)6]2− centrosymmetric dimers. Magnetic measurements show that the hexanuclear magnetic core has an S = 4 ground state.The synthesis and magnetic properties of a mixed-metal [MnIII6 CaII2] polymeric complex are reported.Research Highlights►Photosystem II. ►Manganese–calcium cluster. ►Magnetism/

The reaction of MnCl2·4H2O with DL-valine (Val) in MeOH in the presence of Et-saoH2 (2-hydroxypropiophenone oxime) and NEt4OH forms the complex [MnIII3MnIV2O2(CH3O)(Et-sao)6(Val)]·Val·1.5H2O (1·Val·1.5H2O) in very good yields. A similar reaction of MnCl2·4H2O with Glycine (Gly) in MeOH in the presence of saoH2 (salicylaldoxime) and Ca(OH)2 yields the complex [MnIII3O(sao)3(Gly)Cl(MeOH)3]·1.87 MeOH·0.13H2O (2·1.87 MeOH·0.13H2O). Replacing saoH2 with Me–saoH2 (2-hydroxyethanone oxime) and Gly with HPABA (para-aminobenzoic acid) in the presence of CH3ONa in MeOH forms the complex [Mn6O2(PABA)2(Me-sao)6(MeOH)4(H2O)2]·2[Mn6O2(PABA)2(Me-sao)6(MeOH)2]·11 MeOH (3·11 MeOH) in moderate yields. Magnetic studies for 1 and 2 reveal the presence of both ferromagnetic and antiferromagnetic interactions, leading to S = 2 ground states for both complexes. Complexes 1 and 2 represent the first examples of polynuclear manganese complexes with any naturally occurring α-amino acid, while 3 is the first structurally characterised example of a manganese para-aminobenzoate complex.

The reaction of Mn(O2CMe)2·2H2O with Me-saoH2 (Me-saoH2= 2-hydroxyphenylethanone oxime) in MeCN forms the complex [MnIII4(Me-sao)4(Me-saoH)4] (1) in good yields. Replacing Me-saoH2 with Naphth-saoH2 (Naphth-saoH2 = 2-hydroxy-1-napthaldoxime) in the presence of CH3ONa forms the complex [MnIII4(Naphth-sao)4(Naphth-saoH)4] (2) in low yields, while the reaction between Mn(ClO4)2·6H2O, Et-saoH2 (Et-saoH2= 2-hydroxypropiophenone oxime) and NBu4OH in MeCN gives the complex [MnIII4(Et-sao)4(Et-saoH)4] (3) in moderate yields. All three tetrametallic cages exclusively contain MnIII centres arranged in a “cube”-like topology, in which the metal centres are connected by–N–Ooximate groups. The magnetic properties of 1–3 are near identical, revealing the presence of only ferromagnetic interactions between the metal ions leading to high-spin ground states of S = 8. The complexes display frequency dependent out-of-phase signals in ac susceptibility studies and, in the case of 1 single-molecule magnetism has been observed by means of single-crystal hysteresis loop measurements.

The first polymetallic Mn complex containing an amino acid (the pro-ligand DL-valine) is reported.

The use of N-salicylidene-o-aminophenol (H2saph) in 4f-metal chemistry has led to the isolation of seven new isostructural lanthanide(III) [LnIII] complexes. More specifically the Ln(NO3)3·xH2O/H2saph/Et3N (1:1:1) reaction mixtures in DMF/MeCN gave complexes [Ln2(NO3)2(saph)2(DMF)4] (Ln = Sm (1); Eu (2); Gd (3); Tb (4); Dy (5); Ho (6); Er (7)) in good yields (∼65%). The structures of the isomorphous complexes 3 and 5 were solved by single-crystal X-ray crystallography; the other complexes are proposed to be isostructural with 3 and 5 based on elemental analyses, IR spectra and powder XRD patterns. The two LnIII atoms in the centrosymmetric molecules of 3 and 5 are doubly bridged by the deprotonated iminophenolato oxygen atoms of two nearly planar η1:η1:η2:μ saph2− ligands. The imino nitrogen and five terminal oxygen atoms (the salicylaldiminate, two from one bidentate chelating nitrato group and two from two DMF ligands) complete square antiprismatic coordination at each metal centre. The IR spectra of the complexes are discussed in terms of the coordination modes of the ligands present in the complexes. Solid-state emission studies for all 1–7 display identical ligand-based photoluminescence. Dc magnetic susceptibility studies in the 2–300 K range reveal the presence of a weak, intramolecular antiferromagnetic exchange interaction (J = −0.19(1) cm−1 based on the spin Hamiltonian H = −J(ŜGd·ŜGd′)) for 3 and probably ferromagnetic exchange interaction within the molecules of 4 and 5. Ac magnetic susceptibility measurements in zero dc field show temperature- and frequency-dependent out-of-phase signals with two well defined, thermally-activated processes for 5, suggesting potential single-molecule magnetism character. The Ueff value is 17.4 cm−1 for the higher temperature process and 16.2 cm−1 for the lower temperature one. The combination of photoluminescence and single-molecule behaviour in the DyIII2 complex 5 is critically discussed.

The use of LH3 (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) and aibH (2-amino-isobutyric acid) in 4f chemistry has led to the isolation of eight new isostructural lanthanide complexes. More specifically, the reaction of the corresponding lanthanide nitrate salt with LH3 and aibH in MeOH, under solvothermal conditions in the presence of NEt3, led to the isolation and characterization of seven complexes with the general formulae [LnIII7(OH)2(L′)9(aib)]·4MeOH (Ln = Gd, 1·4MeOH; Tb, 2·4MeOH; Dy, 3·4MeOH; Ho, 4·4MeOH; Er, 5·4MeOH; Tm, 6·4MeOH; Yb, 7·4MeOH L′ = the dianion of the Schiff base between naphthalene aldehyde and 2-amino-isobutyric acid). Furthermore, the isostructural YIII analogue, cluster [YIII7(OH)2(L′)9(aib)]·4MeOH (8·4MeOH), was synthesized in a similar manner to 1–7. The structure of all eight clusters describes a distorted [MIII6] octahedron which encapsulates a seventh MIII ion in an off-centre fashion. Dc magnetic susceptibility studies in the 5–300 K range for complexes 1–7 reveal the presence of dominant antiferromagnetic exchange interactions within the metallic clusters as evidenced by the negative Weiss constant, θ, while ac magnetic susceptibility measurements show temperature and frequency dependent out-of-phase signals for the [DyIII7] analogue (3·4MeOH), suggesting potential single molecule magnetism character. Furthermore, for complex 1, simulation of its dc magnetic susceptibility data yielded very weak antiferromagnetic interactions within the metallic centres. Solid-state emission studies for all 1–8 clusters display ligand-based emission, while extended 1D and 2D NMR studies for 8·4MeOH reveal that the species retain their structural integrity in solution. In addition, TGA measurements for 1, 3 and 7 revealed excellent thermal stability up to 340 °C for the clusters.

The first polymetallic Mn complex containing an amino acid (the pro-ligand DL-valine) is reported.

Employment of H3L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal manganese-lanthanide cluster chemistry has led to the isolation of five new octametallic heteronuclear isostructural [MnIII6LnIII2] complexes. More specifically, the reaction of Mn(ClO4)2·6H2O with H3L and the corresponding lanthanide nitrate in MeCN in the presence of a base, NEt3, yielded four complexes with the general formula [MnIII6LnIII2O2(OH)2(H2O)2(HL)6(NO3)6]·6MeCN·0.5H2O (Ln: Gd, 1·6MeCN·0.5H2O; Tb, 2·6MeCN·0.5H2O; Dy, 3·6MeCN·0.5H2O; Er, 4·6MeCN·0.5H2O). Furthermore, the YIII analogue, [MnIII6YIII2O2(OH)2(H2O)2(HL)6(NO3)6]·6MeCN·0.5H2O (5·6MeCN·0.5H2O), was also synthesized in the same manner. All five clusters describe a central rod-like topology consisting of four face-sharing defective cubane metallic units, forming a planar hexametallic [MnIII4LnIII2] core, which is further capped by two MnIII ions. Dc magnetic susceptibility studies in the 5–300 K range for complexes 1–5 reveal the presence of dominant antiferromagnetic exchange interactions within the metallic clusters, while ac magnetic susceptibility measurements show temperature and frequency dependent out-of-phase signals for the DyIII analogue (3·6MeCN·0.5H2O), suggesting potential single molecule magnetism character. Furthermore, the YIII analogue yielded a diamagnetic ground-state for the [MnIII6] core, thus proving that the SMM character displayed by 3·6MeCN·0.5H2O is due to the presence of the DyIII centres.

The use of H3L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal manganese–lanthanide carboxylate cluster chemistry has led to the isolation of two new dodecametallic heteronuclear isostructural [MnIII6LnIII6] complexes (Ln = Gd, Dy), with the Dy analogue displaying temperature and frequency dependent out-of-phase signals suggesting possible single molecule magnetism behaviour.

The reaction of Mn(O2CMe)2·2H2O with Me-saoH2 (Me-saoH2= 2-hydroxyphenylethanone oxime) in MeCN forms the complex [MnIII4(Me-sao)4(Me-saoH)4] (1) in good yields. Replacing Me-saoH2 with Naphth-saoH2 (Naphth-saoH2 = 2-hydroxy-1-napthaldoxime) in the presence of CH3ONa forms the complex [MnIII4(Naphth-sao)4(Naphth-saoH)4] (2) in low yields, while the reaction between Mn(ClO4)2·6H2O, Et-saoH2 (Et-saoH2= 2-hydroxypropiophenone oxime) and NBu4OH in MeCN gives the complex [MnIII4(Et-sao)4(Et-saoH)4] (3) in moderate yields. All three tetrametallic cages exclusively contain MnIII centres arranged in a “cube”-like topology, in which the metal centres are connected by–N–Ooximate groups. The magnetic properties of 1–3 are near identical, revealing the presence of only ferromagnetic interactions between the metal ions leading to high-spin ground states of S = 8. The complexes display frequency dependent out-of-phase signals in ac susceptibility studies and, in the case of 1 single-molecule magnetism has been observed by means of single-crystal hysteresis loop measurements.

Employment of H3L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal copper-lanthanide cluster chemistry has led to the isolation of four new enneanuclear heteronuclear isostructural [CuII7LnIII2] complexes. More specifically, the solvothermal reaction of Cu2(OAc)4·2H2O with H3L and the corresponding lanthanide nitrate salt in MeCN in the presence of a base, NEt3, yielded three complexes with the general formula [CuII7LnIII2(L)4(HL)2(OAc)4]·2MeCN (Ln: Gd, 1·2MeCN; Tb, 2·2MeCN; Dy, 3·2MeCN), while in addition the YIII analogue, [CuII7YIII2(L)4(HL)2(OAc)4]·2MeCN (4·2MeCN), was also synthesized in the same manner. The structure of the cluster describes two corner-sharing [Cu3Ln] cubane metallic units, each one further connected to one CuII ion. Dc magnetic susceptibility studies in the 5–300 K range for complexes 1–4 reveal the presence of both ferromagnetic and antiferromagnetic exchange interactions within the metallic clusters.

The use of phamidoxH2 (phamidoxH2 = 2-dihydroxy-2-phenylacetamidine) in manganese cluster chemistry led to the synthesis and characterization of a hexametallic and an octametallic MnIII cluster, both of which display a S = 3 ground state.

The reaction of MnCl2·4H2O with DL-valine (Val) in MeOH in the presence of Et-saoH2 (2-hydroxypropiophenone oxime) and NEt4OH forms the complex [MnIII3MnIV2O2(CH3O)(Et-sao)6(Val)]·Val·1.5H2O (1·Val·1.5H2O) in very good yields. A similar reaction of MnCl2·4H2O with Glycine (Gly) in MeOH in the presence of saoH2 (salicylaldoxime) and Ca(OH)2 yields the complex [MnIII3O(sao)3(Gly)Cl(MeOH)3]·1.87 MeOH·0.13H2O (2·1.87 MeOH·0.13H2O). Replacing saoH2 with Me–saoH2 (2-hydroxyethanone oxime) and Gly with HPABA (para-aminobenzoic acid) in the presence of CH3ONa in MeOH forms the complex [Mn6O2(PABA)2(Me-sao)6(MeOH)4(H2O)2]·2[Mn6O2(PABA)2(Me-sao)6(MeOH)2]·11 MeOH (3·11 MeOH) in moderate yields. Magnetic studies for 1 and 2 reveal the presence of both ferromagnetic and antiferromagnetic interactions, leading to S = 2 ground states for both complexes. Complexes 1 and 2 represent the first examples of polynuclear manganese complexes with any naturally occurring α-amino acid, while 3 is the first structurally characterised example of a manganese para-aminobenzoate complex.

The reaction of Mn(ClO4)2·6H2O with Ph-saoH2 (Ph-saoH2 = 2-hydroxybenzophenone oxime) in MeCN in the presence of sodium propionate forms the complex [MnIII6O2(Ph-sao)6(prop)2(MeCN)2]·5.27MeCN (1·5.27MeCN) (prop = propionate). Repeating the same reaction in EtOH produces the complex [MnIII6O2(Ph-sao)6(prop)2(EtOH)4] (2). Complexes 1 and 2 may be considered as structural isomers, since they display the same metallic core but different coordination modes of the propionate ligands; bridging in 1 and terminal in 2. Performing similar reactions and switching from sodium propionate to sodium adamantane-carboxylate (NaO2C-ada) and sodium pivalate (Napiv) in the presence of NEt4OH yields the complexes [MnIII6O2(Ph-sao)6(O2C-ada)2(MeOH)4] (3) and [MnIII6O2(Ph-sao)6(piv)2(EtOH)4]·0.5Et2O (4·0.5Et2O), respectively. All four complexes contain the same {MnIII3O(Ph-sao)3} building block. Variable temperature magnetic susceptibility and magnetization studies show that all complexes possess an S = 4 ground-state.

The use of 2-amino-isobutyric acid in Co/Ln chemistry has led to the isolation of two unique [CoII6LnIII] 3d-4f metallic cages in which the LnIII centre (Ln = Eu, Dy) is encapsulated within a CoII6 trigonal prism.