The synthesis and characterisation of a large family of trimetallic [MnIII3] Single-Molecule Magnets is presented. The complexes reported can be divided into three categories with general formulae (type 1) [MnIII3O(R-sao)3(X)(sol)3-4] (where R = H, Me, tBu; X = −O2CR (R = H, Me, Ph etc); sol = py and/or H2O), (type 2) [MnIII3O(R-sao)3(X)(sol)3-5] (where R = Me, Et, Ph, tBu; X = −O2CR (R = H, Me, Ph etc); sol = MeOH, EtOH and/or H2O), and (type 3) [MnIII3O(R-sao)3(sol)3(XO4)] (where R = H, Et, Ph, naphth; sol = py, MeOH, β-pic, Et-py, tBu-py; X = Cl, Re). We show that deliberate structural distortions of the molecule can be used to tune the observed magnetic properties. In the crystals the ferromagnetic triangles are involved in extensive inter-molecular H-bonding which is clearly manifested in the magnetic behaviour, producing exchange-biased SMMs. These interactions can be removed by ligand replacement to give “simpler” SMMs.

The synthesis and characterisation of a large family of trimetallic [MnIII3] Single-Molecule Magnets is presented. The complexes reported can be divided into three categories with general formulae (type 1) [MnIII3O(R-sao)3(X)(sol)3-4] (where R = H, Me, tBu; X = −O2CR (R = H, Me, Ph etc); sol = py and/or H2O), (type 2) [MnIII3O(R-sao)3(X)(sol)3-5] (where R = Me, Et, Ph, tBu; X = −O2CR (R = H, Me, Ph etc); sol = MeOH, EtOH and/or H2O), and (type 3) [MnIII3O(R-sao)3(sol)3(XO4)] (where R = H, Et, Ph, naphth; sol = py, MeOH, β-pic, Et-py, tBu-py; X = Cl, Re). We show that deliberate structural distortions of the molecule can be used to tune the observed magnetic properties. In the crystals the ferromagnetic triangles are involved in extensive inter-molecular H-bonding which is clearly manifested in the magnetic behaviour, producing exchange-biased SMMs. These interactions can be removed by ligand replacement to give “simpler” SMMs.

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 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.

A new family of hexametallic [MnIII6] Single-Molecule Magnets with general formula [Mn6O2(R-sao)6(X)2(MeOH)4-6] (R = H, Me, Et or Ph; X = O2PHPh or O2P(Ph)2) have been synthesised and characterised. The molecules are new members of the [Mn6] family of SMMs in which the carboxylate ligands have been replaced with phenyl- and diphenylphosphinate. The magnetic cores remain largely unaltered meaning that structural distortions of the Mn–N–O–Mn torsion angles in the [Mn3O] subunits can be used to tune the magnetic properties, switching pairwise exchange interactions from antiferromagnetic to ferromagnetic. The results suggest that the Mn6 building block, be it ferro- or antiferromagnetically coupled, could be an important building block for the formation of novel, functional 0-3D materials.

A new family of hexametallic [MnIII6] Single-Molecule Magnets with general formula [Mn6O2(R-sao)6(X)2(MeOH)4-6] (R = H, Me, Et or Ph; X = O2PHPh or O2P(Ph)2) have been synthesised and characterised. The molecules are new members of the [Mn6] family of SMMs in which the carboxylate ligands have been replaced with phenyl- and diphenylphosphinate. The magnetic cores remain largely unaltered meaning that structural distortions of the Mn–N–O–Mn torsion angles in the [Mn3O] subunits can be used to tune the magnetic properties, switching pairwise exchange interactions from antiferromagnetic to ferromagnetic. The results suggest that the Mn6 building block, be it ferro- or antiferromagnetically coupled, could be an important building block for the formation of novel, functional 0-3D materials.

The synthesis and magnetic properties of the compounds [HNEt3][Fe2(OMe)(Ph-sao)2 (Ph-saoH)2]·5MeOH (1·5MeOH), [Fe3O(Et-sao)(O2CPh)5(MeOH)2]·3MeOH (2·3MeOH), [Fe4(Me-sao)4(Me-saoH)4] (3), [HNEt3]2[Fe6O2(Me-sao)4(SO4)2(OMe)4(MeOH)2] (4), [Fe8O3(Me-sao)3(tea)(teaH)3(O2CMe)3] (5), [Fe8O3(Et-sao)3(tea)(teaH)3(O2CMe)3] (6), and [Fe8O3(Ph-sao)3(tea)(teaH)3(O2CMe)3] (7) are reported (Me-saoH2 is 2′-hydroxyacetophenone oxime, Et-saoH2 is 2′-hydroxypropiophenone oxime and Ph-saoH2 is 2-hydroxybenzophenone oxime). 1–7 are the first FeIII compounds synthesised using the derivatised salicylaldoxime ligands, R-saoH2. 1 is prepared by treatment of Fe2(SO4)3·6H2O with Ph-saoH2 in the presence of NEt3 in MeOH; 2 prepared by treatment of Fe(ClO4)2·6H2O with Et-saoH2 and NaO2CPh in the presence of NEt4OH in MeOH; 3 prepared by treatment of Fe(ClO4)2·6H2O with Me-saoH2 and NaO2CCMe3 in the presence of NEt4OH in MeOH; and 4 prepared by treatment of Fe2(SO4)3·6H2O with Me-saoH2 in the presence of NEt3 in MeOH. 4 is a rare example of a polynuclear iron complex containing a coordinated SO42− ion. Compounds 5–7 are prepared by treatment of Fe(O2CMe)2 with Me-saoH2 (5), Et-saoH2 (6), Ph-saoH2 (7) in the presence of H3tea (triethanolamine) in MeOH, and represent the largest nuclearity FeIII clusters containing salicyladoxime-based ligands, joining a surprisingly small family of characterised octanuclear Fe complexes. Variable temperature magnetic susceptibilty measurements of 1,3 and 5–7 reveal all five complexes possess S = 0 spin ground states; 2 possesses an S = 1/2 spin ground state, while 4 has an S = 4 ± 1 spin ground state.

The synthesis and magnetic properties of the compounds [HNEt3][Fe2(OMe)(Ph-sao)2 (Ph-saoH)2]·5MeOH (1·5MeOH), [Fe3O(Et-sao)(O2CPh)5(MeOH)2]·3MeOH (2·3MeOH), [Fe4(Me-sao)4(Me-saoH)4] (3), [HNEt3]2[Fe6O2(Me-sao)4(SO4)2(OMe)4(MeOH)2] (4), [Fe8O3(Me-sao)3(tea)(teaH)3(O2CMe)3] (5), [Fe8O3(Et-sao)3(tea)(teaH)3(O2CMe)3] (6), and [Fe8O3(Ph-sao)3(tea)(teaH)3(O2CMe)3] (7) are reported (Me-saoH2 is 2′-hydroxyacetophenone oxime, Et-saoH2 is 2′-hydroxypropiophenone oxime and Ph-saoH2 is 2-hydroxybenzophenone oxime). 1–7 are the first FeIII compounds synthesised using the derivatised salicylaldoxime ligands, R-saoH2. 1 is prepared by treatment of Fe2(SO4)3·6H2O with Ph-saoH2 in the presence of NEt3 in MeOH; 2 prepared by treatment of Fe(ClO4)2·6H2O with Et-saoH2 and NaO2CPh in the presence of NEt4OH in MeOH; 3 prepared by treatment of Fe(ClO4)2·6H2O with Me-saoH2 and NaO2CCMe3 in the presence of NEt4OH in MeOH; and 4 prepared by treatment of Fe2(SO4)3·6H2O with Me-saoH2 in the presence of NEt3 in MeOH. 4 is a rare example of a polynuclear iron complex containing a coordinated SO42− ion. Compounds 5–7 are prepared by treatment of Fe(O2CMe)2 with Me-saoH2 (5), Et-saoH2 (6), Ph-saoH2 (7) in the presence of H3tea (triethanolamine) in MeOH, and represent the largest nuclearity FeIII clusters containing salicyladoxime-based ligands, joining a surprisingly small family of characterised octanuclear Fe complexes. Variable temperature magnetic susceptibilty measurements of 1,3 and 5–7 reveal all five complexes possess S = 0 spin ground states; 2 possesses an S = 1/2 spin ground state, while 4 has an S = 4 ± 1 spin ground state.

The synthesis and magnetic properties of three new members of a family of salicyaldoxime based [Mn6] single-molecule magnets possessing new structural types, core topologies and Mn oxidation state distributions are reported. The isostructural complexes [MnIII6O2(R-sao)6(X)2(EtOH)6] (R = Et, X = Br (1); R = Me, X = I (2)) exhibit single-molecule magnet behaviour with spin Hamiltonian parameters S = 12, g = 1.98 and D = −0.36 cm−1 in both cases. The hexametallic cluster [MnIII4MnIV2O2(OMe)4(Et-sao)6(MeOH)2]·MeOH (3·MeOH) possesses a planar rod-like topology and a mixed valent [MnIV4MnIII2] core, which is unprecedented in this family of [Mn6] SMMs.

The synthesis and magnetic properties of three new members of a family of salicyaldoxime based [Mn6] single-molecule magnets possessing new structural types, core topologies and Mn oxidation state distributions are reported. The isostructural complexes [MnIII6O2(R-sao)6(X)2(EtOH)6] (R = Et, X = Br (1); R = Me, X = I (2)) exhibit single-molecule magnet behaviour with spin Hamiltonian parameters S = 12, g = 1.98 and D = −0.36 cm−1 in both cases. The hexametallic cluster [MnIII4MnIV2O2(OMe)4(Et-sao)6(MeOH)2]·MeOH (3·MeOH) possesses a planar rod-like topology and a mixed valent [MnIV4MnIII2] core, which is unprecedented in this family of [Mn6] SMMs.

The synthesis and characterisation of a large family of hexametallic [MnIII6] Single-Molecule Magnets of general formula [MnIII6O2(R-sao)6(X)2(sol)4–6] (where R = H, Me, Et; X = −O2CR′ (R′ = H, Me, Ph etc) or Hal−; sol = EtOH, MeOH and/or H2O) are presented. We show how deliberate structural distortions of the [Mn3O] trinuclear moieties within the [Mn6] complexes are used to tune their magnetic properties. These findings highlight a qualitative magneto-structural correlation whereby the type (anti- or ferromagnetic) of each Mn2 pairwise magnetic exchange is dominated by the magnitude of each individual Mn-N-O-Mn torsion angle. The observation of magneto-structural correlations on such large polymetallic complexes is rare and represents one of the largest studies of this kind.

The synthesis and characterisation of a large family of hexametallic [MnIII6] Single-Molecule Magnets of general formula [MnIII6O2(R-sao)6(X)2(sol)4–6] (where R = H, Me, Et; X = −O2CR′ (R′ = H, Me, Ph etc) or Hal−; sol = EtOH, MeOH and/or H2O) are presented. We show how deliberate structural distortions of the [Mn3O] trinuclear moieties within the [Mn6] complexes are used to tune their magnetic properties. These findings highlight a qualitative magneto-structural correlation whereby the type (anti- or ferromagnetic) of each Mn2 pairwise magnetic exchange is dominated by the magnitude of each individual Mn-N-O-Mn torsion angle. The observation of magneto-structural correlations on such large polymetallic complexes is rare and represents one of the largest studies of this kind.

The syntheses, structures and magnetic properties of nine new iron complexes containing salicylaldoxime (saoH2) or derivatised salicylaldoximes (R-saoH2), [Fe3O(OMe)(Ph-sao)2 Cl2(py)3]·2MeOH (1·2MeOH), [Fe3O(OMe)(Ph-sao)2Br2(py)3]·Et2O (2·Et2O), [Fe4(Ph-sao)4F4(py)4]·1.5MeOH (3·1.5MeOH), [Fe6O2(OH)2(Et-sao)2(Et-saoH)2(O2CPh)6] (4), [HNEt3]2[Fe6O2(OH)2(Et-sao)4(O2CPh(Me)2)6]·2MeCN (5·2MeCN), [Fe6O2(O2CPh)10(3-tBut-5-NO2-sao)2(H2O)2]·2MeCN (6·2MeCN), [Fe6O2(O2CCH2Ph)10(3-tBut-sao)2(H2O)2]·5MeCN (7·5MeCN), {[Fe6Na3O(OH)4(Me-sao)6(OMe)3(H2O)3(MeOH)6]·MeOH}n (8·MeOH) and [HNEt3]2[Fe12Na4O2(OH)8(sao)12(OMe)6(MeOH)10] (9) are discussed. The predominant building block appears to be the triangular [Fe3O(R-sao)3]+ species which can self-assemble into more elaborate arrays depending on reaction conditions. An interesting observation is that the R-saoH−/R-sao2− ligand system tends to adopt coordination modes similar to carboxylates. The most unusual molecule is the [Fe4F4] molecular square, 3. While Cl− and Br− appear to act only as terminal ligands, the F− ions bridge making a telling impact on molecular structure and topology.

The syntheses, structures and magnetic properties of nine new iron complexes containing salicylaldoxime (saoH2) or derivatised salicylaldoximes (R-saoH2), [Fe3O(OMe)(Ph-sao)2 Cl2(py)3]·2MeOH (1·2MeOH), [Fe3O(OMe)(Ph-sao)2Br2(py)3]·Et2O (2·Et2O), [Fe4(Ph-sao)4F4(py)4]·1.5MeOH (3·1.5MeOH), [Fe6O2(OH)2(Et-sao)2(Et-saoH)2(O2CPh)6] (4), [HNEt3]2[Fe6O2(OH)2(Et-sao)4(O2CPh(Me)2)6]·2MeCN (5·2MeCN), [Fe6O2(O2CPh)10(3-tBut-5-NO2-sao)2(H2O)2]·2MeCN (6·2MeCN), [Fe6O2(O2CCH2Ph)10(3-tBut-sao)2(H2O)2]·5MeCN (7·5MeCN), {[Fe6Na3O(OH)4(Me-sao)6(OMe)3(H2O)3(MeOH)6]·MeOH}n (8·MeOH) and [HNEt3]2[Fe12Na4O2(OH)8(sao)12(OMe)6(MeOH)10] (9) are discussed. The predominant building block appears to be the triangular [Fe3O(R-sao)3]+ species which can self-assemble into more elaborate arrays depending on reaction conditions. An interesting observation is that the R-saoH−/R-sao2− ligand system tends to adopt coordination modes similar to carboxylates. The most unusual molecule is the [Fe4F4] molecular square, 3. While Cl− and Br− appear to act only as terminal ligands, the F− ions bridge making a telling impact on molecular structure and topology.

The syntheses, structures and magnetic properties of six iron complexes stabilised with the derivatised salicylaldoxime ligands Me-saoH2 (2-hydroxyethanone oxime) and Et-saoH2 (2-hydroxypropiophenone oxime) are discussed. The four hexanuclear and two octanuclear complexes of formulae [Fe8O2(OMe)4(Me-sao)6Br4(py)4]·2Et2O·MeOH (1·2Et2O·MeOH), [Fe8O2(OMe)3.85(N3)4.15(Me-sao)6(py)2] (2), [Fe6O2(O2CPh-4-NO2)4(Me-sao)2(OMe)4Cl2(py)2] (3), [Fe6O2(O2CPh-4-NO2)4(Et-sao)2(OMe)4Cl2(py)2]·2Et2O·MeOH (4·2Et2O·MeOH), [HNEt3]2[Fe6O2(Me-sao)4(SO4)2(OMe)4(MeOH)2] (5) and [HNEt3]2[Fe6O2(Et-sao)4(SO4)2(OMe)4(MeOH)2] (6) all are built from a series of edge-sharing [Fe4(μ4-O)]10+ tetrahedra. Complexes 1 and 2 display a new μ4-coordination mode of the oxime ligand and join a small group of Fe-phenolic oxime complexes with nuclearity greater than six.

The syntheses, structures and magnetic properties of six iron complexes stabilised with the derivatised salicylaldoxime ligands Me-saoH2 (2-hydroxyethanone oxime) and Et-saoH2 (2-hydroxypropiophenone oxime) are discussed. The four hexanuclear and two octanuclear complexes of formulae [Fe8O2(OMe)4(Me-sao)6Br4(py)4]·2Et2O·MeOH (1·2Et2O·MeOH), [Fe8O2(OMe)3.85(N3)4.15(Me-sao)6(py)2] (2), [Fe6O2(O2CPh-4-NO2)4(Me-sao)2(OMe)4Cl2(py)2] (3), [Fe6O2(O2CPh-4-NO2)4(Et-sao)2(OMe)4Cl2(py)2]·2Et2O·MeOH (4·2Et2O·MeOH), [HNEt3]2[Fe6O2(Me-sao)4(SO4)2(OMe)4(MeOH)2] (5) and [HNEt3]2[Fe6O2(Et-sao)4(SO4)2(OMe)4(MeOH)2] (6) all are built from a series of edge-sharing [Fe4(μ4-O)]10+ tetrahedra. Complexes 1 and 2 display a new μ4-coordination mode of the oxime ligand and join a small group of Fe-phenolic oxime complexes with nuclearity greater than six.

The first 3d-4f clusters built using derivatised salicylaldoximes (R-saoH2) describe unusual hexagonal prisms. Replacement of the paramagnetic Gd(III) ions with diamagnetic Ln(III) ions allows for a more thorough understanding of the magnetic properties, whilst replacement with Tb(III) doubles Ueff.

The first 3d-4f clusters built using derivatised salicylaldoximes (R-saoH2) describe unusual hexagonal prisms. Replacement of the paramagnetic Gd(III) ions with diamagnetic Ln(III) ions allows for a more thorough understanding of the magnetic properties, whilst replacement with Tb(III) doubles Ueff.

The reaction of Mn(ClO4)2·6H2O, a derivatised phenolic oxime (R-saoH2) and the ligand tris(2-pyridylmethyl)amine (tpa) in a basic alcoholic solution leads to the formation of a family of cluster compounds of general formula [MnIII2O(R-sao)(tpa)2](ClO4)2 (1, R = H; 2, R = Me; 3, R = Et; 4, R = Ph). The structure is that of a simple, albeit asymmetric, dimer of two MnIII ions bridged through one μ-O2− ion and the –N–O– moiety of the phenolic oxime. Magnetometry reveals that the exchange interaction between the two MnIII ions in complexes 1, 3 and 4 is antiferromagnetic, but that for complex 2 is ferromagnetic. A theoretically developed magneto-structural correlation reveals that the dominant structural parameter influencing the sign and magnitude of the pairwise interaction is the dihedral Mn–O–N–Mn (torsion) angle. A linear correlation is found, with the magnitude of J varying significantly as the dihedral angle is altered. As the torsion angle increases the AF exchange decreases, matching the experimentally determined data. DFT calculations reveal that the dyz|π*|dyz interaction decreases as the dihedral angle increases leading to ferromagnetic coupling at larger angles.

The reaction of Mn(ClO4)2·6H2O, a derivatised phenolic oxime (R-saoH2) and the ligand tris(2-pyridylmethyl)amine (tpa) in a basic alcoholic solution leads to the formation of a family of cluster compounds of general formula [MnIII2O(R-sao)(tpa)2](ClO4)2 (1, R = H; 2, R = Me; 3, R = Et; 4, R = Ph). The structure is that of a simple, albeit asymmetric, dimer of two MnIII ions bridged through one μ-O2− ion and the –N–O– moiety of the phenolic oxime. Magnetometry reveals that the exchange interaction between the two MnIII ions in complexes 1, 3 and 4 is antiferromagnetic, but that for complex 2 is ferromagnetic. A theoretically developed magneto-structural correlation reveals that the dominant structural parameter influencing the sign and magnitude of the pairwise interaction is the dihedral Mn–O–N–Mn (torsion) angle. A linear correlation is found, with the magnitude of J varying significantly as the dihedral angle is altered. As the torsion angle increases the AF exchange decreases, matching the experimentally determined data. DFT calculations reveal that the dyz|π*|dyz interaction decreases as the dihedral angle increases leading to ferromagnetic coupling at larger angles.

The linear [M(CN)2]− (M = Au, Ag) anions can be used as metalloligands in oxime-based Mn chemistry to afford 1D chains of [MnIII6] single-molecule magnets (SMMs).

The linear [M(CN)2]− (M = Au, Ag) anions can be used as metalloligands in oxime-based Mn chemistry to afford 1D chains of [MnIII6] single-molecule magnets (SMMs).

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

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

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 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.

A new 1D coordination polymer comprised of [MnIII6O2(Et-sao)6(EtOH)4(H2O)2]2+ units and bithiophene dicarboxylato was synthesized by mixing EtsaoH2 (salicylaldoxime), H2btda (2,2′-bithiophene-5,5′-dicarboxylic acid) and Mn(ClO4)2·6H2O in the presence of NEt4OH. The crystal structure was determined and consists of Mn6 clusters bridged by the bithiophene dicarboxylato ligands coordinated to two of the MnIII ions of the Mn6 polynuclear complex. Direct current magnetic measurements show an overall ferromagnetic interaction between the MnIII ions within the Mn6 cluster leading to an S = 12 ground state for the Mn6 unit. Furthermore, this compound presents single-molecule magnet behaviour. Slow relaxation of the magnetization is observed at low temperature following a thermal activated regime with Ueff≈ 50 K and τ0≈ 2.2 10−10 s. The magnetic measurements do not show any noticeable interaction between the Mn6 clusters through the bithiophene dicarboxylato bridges.

A new 1D coordination polymer comprised of [MnIII6O2(Et-sao)6(EtOH)4(H2O)2]2+ units and bithiophene dicarboxylato was synthesized by mixing EtsaoH2 (salicylaldoxime), H2btda (2,2′-bithiophene-5,5′-dicarboxylic acid) and Mn(ClO4)2·6H2O in the presence of NEt4OH. The crystal structure was determined and consists of Mn6 clusters bridged by the bithiophene dicarboxylato ligands coordinated to two of the MnIII ions of the Mn6 polynuclear complex. Direct current magnetic measurements show an overall ferromagnetic interaction between the MnIII ions within the Mn6 cluster leading to an S = 12 ground state for the Mn6 unit. Furthermore, this compound presents single-molecule magnet behaviour. Slow relaxation of the magnetization is observed at low temperature following a thermal activated regime with Ueff≈ 50 K and τ0≈ 2.2 10−10 s. The magnetic measurements do not show any noticeable interaction between the Mn6 clusters through the bithiophene dicarboxylato bridges.

Two novel coaxial double-screw-propeller heptanuclear 3d–4f cluster complexes are ferromagnetic: one exhibits a large magnetocaloric effect while the other a magnetic relaxation behavior, depending on the lanthanoid ions used.

Two novel coaxial double-screw-propeller heptanuclear 3d–4f cluster complexes are ferromagnetic: one exhibits a large magnetocaloric effect while the other a magnetic relaxation behavior, depending on the lanthanoid ions used.