1,3-Bis(1-methyl-1H-tetrazol-5-yl)propane and its coordination polymers with Cu2Cl4 and Cu3Cl6 units

Abstract

1,3-Bis(1-methyl-1H-tetrazol-5-yl)propane (bmtp) was prepared by a procedure including regioselective tert-butylation of 1,3-bis(1H-tetrazol-5-yl)propane and exhaustive methylation of the obtained 1,3-bis(2-tert-butyl-1H-tetrazol-5-yl)propane, followed by removal of the tert-butyl group from the tetrazolium salt under acidic conditions. The ligand bmtp reacts with CuCl2·2H2O in ethanol to give the complexes [Cu3(bmtp)2Cl6(H2O)2]n and [Cu(bmtp)Cl2]n. The transformation of [Cu(bmtp)Cl2]n into [Cu3(bmtp)2Cl6(H2O)2]n is observed in ethanol. According to single crystal X-ray analysis, [Cu(bmtp)Cl2]n was obtained as a mixture of polymorphic forms. They are all 1D coordination polymers, in which polymeric chains include Cu2Cl4 units linked to each other by two bridging ligands via the tetrazole ring N4 atoms. [Cu3(bmtp)2Cl6(H2O)2]n presents a 2D coordination polymer, including Cu3Cl6 units bonded to four others by ligand molecules. In this complex, the tetrazole ligands show monodentate N4 and bridging N3,N4 coordination. The temperature-dependent magnetic susceptibility measurements of this complex revealed that the copper(II) ions are antiferromagnetically coupled, showing a coupling constant J of −4.0 cm−1.