Synthesis, structures and magnetic properties of copper(II) complexes with 1,2,3-triazole derivate as ligand: a single-crystal-to-single-crystal transformation from mononuclear to polymeric complex of copper(II)

Abstract

A new mononuclear complex Cu(tdp)Br2·MeCN (1, tdp = 2,2′-(1H-1,2,3-triazole-1,4-diyl)dipyridine) has been synthesized, which can transform to a 1D coordination polymer [Cu(tdp)Br2]n (2) under ambient conditions through an irreversible single-crystal-to-single-crystal transformation process. The loss of lattice MeCN molecules in 1 was accompanied by the generation of new covalent bonds and an increase in dimensionality from 0 to 1D, leading to a change in magnetic exchange couplings between the adjacent Cu(II) ions. Magnetic susceptibility measurements indicate that 1 exhibits ferromagnetic interactions between the adjacent Cu(II) centers, while the intrachain magnetic interactions between Cu(II) ions are antiferromagnetic within 2.