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

Using the solvothermal method, we present the comparative preparation of [Ni(L1)Cl(CH3CN)]4 (1), [Ni(L2)Cl(C2H5OH)]4 (2) and [Ni(HL3)2(CH3COO)2]·2DMF (3), where HL1 is (1H-benzimidazol-2-yl)-methanol, HL2 is (6-methyl-1H-benzoimidazol-2-yl)-methanol and HL3 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, P1¯ 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 2–300 K temperature range have also been discussed. The {Ni4O4} core displays dominant ferromagnetic interactions.

Graphical abstractThree new complexes 1–3 have been constructed. The studies show that the position and steric hindrances of the substituted groups are essential in determining the final structures of the assemblies. The {Ni4O4} core displays dominant ferromagnetic interactions due to the nature of the binding modes through μ3-O.Figure optionsDownload full-size imageDownload as PowerPoint slide