Ligand induced diversification from tetranuclear to mononuclear compounds: Syntheses, structures and magnetic properties.

Abstract: Using the solvothermal method, we present the comparative preparation of [Ni(L 1)Cl(CH3CN)]4 (1), [Ni(L 2)Cl(C2H5OH)]4 (2) and [Ni(HL 3)2(CH3COO)2]·2DMF (3), where HL 1 is (1H-benzimidazol-2-yl)-methanol, HL 2 is (6-methyl-1H-benzoimidazol-2-yl)-methanol and HL 3 is 1-(1H-benzoimidazol-2-yl)-ethanol. All the compounds were characterized by elemental analysis, IR and X-ray single-crystal diffraction. Compounds 1 and 2 are tetranuclear clusters with a cubane topology, in which the metal ions and the oxygen atoms from the L ligands occupy alternate vertices of the cubane. However, compound 3 is a mononuclear nickel complex with the triclinic crystal system, space group, different from that of compounds 1 and 2. These results show that the position and space steric hindrance of the substituents groups are essential in determining the final structures of the assemblies. The magnetic properties of 1 and 2 in the 2–300K temperature range have also been discussed. The {Ni4O4} core displays dominant ferromagnetic interactions. [Copyright &y& Elsevier]