Synthesis, crystal structures and magnetic studies of terephthalato-bridged binuclear nickel(II) complexes

Abstract

Two binuclear compounds [Ni 2(pmdtn) 2(tp)(H 2O) 2](ClO 4) 2(H 2O) 4 ( 1) and [Ni 2(pmdtn) 2(tp)(N 3) 2](H 2O) 4 ( 2) have been prepared by using the multibinding terephthalate (=tp) dianion and the tridentate capping ligand N, N, N ′, N ′, N″-pentamethyldiethyltriamine (=pmdtn) and have been characterized by X-ray crystallography and magnetic measurements. The crystal structures of both complexes show distorted octahedral geometries around the Ni(II) centers linked by the tp bridges in a bisbidentate fashion. The dihedral angles between the benzene rings and carboxylate groups correspond to 14.2° for 1 and 21.5° for 2. The intradimer distance of Ni⋯Ni through the tp ligand for 1 and 2 are 10.731 and 10.800 Å, respectively. The magnetic data reveal weak antiferromagnetic interactions transmitted by the tp bridge with J=−0.18 cm −1 ( 1) and −0.02 cm −1 ( 2), which is explained by the structural parameters.