The solvothermal reaction between Cr(acac), MCl·6HO (M = Ni, Co) and 2-hydroxy-4-methyl-6-phenyl-pyridine-3-amidoxime (HL), under basic conditions, led to the synthesis of the heterometallic heptanuclear clusters [MCr(HL)(HL)]·3Cl (M = Ni, 1; Co, 2), with the nickel analogue displaying an S = 9/2 spin ground-state.

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Reaction between NiCl2•6H2O, 2-hydroxy-4-methyl-6-phenyl-pyridine-3-amidoxime (H2L), benzoic acid and M(NO3)3•6H2O (M = Gd, Y) in MeCN under basic conditions, yields the complexes [Ni II 4Gd III 5(PhCOO)10(HL)4(HLzw)4(OH)2(NO3)2]Cl•13.6MeCN•H2O (1•13.6MeCN 2 •H2O) and [Ni II 4Y III 5(PhCOO)10(HL)4(HLzw)4(OH)2(NO3)1.5(H2O)0.5]0.5Cl(NO3)•3H2O (2•3H2O). Both clusters display similar structures, consisting of a bell-shaped {Ni II 4M III 5} unit, in which a linear 'zig-zag' {Ni4} subunit bisects the central {M III 5} 'ring'. Direct (dc) and alternating current (ac) magnetic susceptibility measurements carried out in the 2-300 K temperature range for complexes 1 and 2 revealed ferromagnetic intermolecular interactions, while heat-capacity measurements for the Gd analogue suggest that complex 1 lowers its temperature from T = 9.6 K down to 2.3 K by adiabatically demagnetizing from Bi = 7 T to Bf = 0.