Synthesis, Structures, and Magnetic Properties of Dinuclear Nickel(II) Complexes Containing N,N,N',N'-Tetrakis[(1-methyl-2-benzimidazolyl)methyl]- 2-hydroxy-1,3-diaminopropane and a Thiocyanate Ion

Abstract

Three dinuclear nickel(II) complexes, [Ni2(L-Me)(NCS)(H2O)3](PF6)2 (1), [Ni2(L-Me)(NCS)2 (CH3OH) (H2O)]PF6 (2), and [Ni2(L-Me)(NCS)2(H2O)2]NCS (3) containing HL-Me(HL-Me ＝ N,N,N',N'-tetrakis[(1-methyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane) have been synthesized and characterized by their IR and UV-Vis spectra and magnetic susceptibilities. The crystal structures of the complexes 1’, 2’, and 3’, from which 1, 2, and 3, respectively, are derived, were determined by X-ray crystallography. These complexes are dimeric and only an alkoxo of L-Me－ bridges two octahedral Ni(II) ions. While 2’ and 3’ have symmetrical conformations of L-Me－, that of 1’ is unsymmetrical. Magnetic susceptibility measurements from liquid helium temperature to room temperature showed a weak ferromagnetic exchange coupling between the two nickel(II) ions (2J ＝7.8cm－1, H ＝－2JS1・S2) for 1. On the other hand, antiferromagnetic interactions were observed for 2 and 3 (2J ＝－29.2and －27.8cm－1, respectively).