Transitionmetal complexes with pyrazole-based ligands: Part 21. Thermal decomposition of copper and cobalt halide complexes with 3,5-dimethyl-1- thiocarboxamidepyrazole

Abstract

The thermal decomposition of Cu2L2Cl4, Cu2L2Cl2, Cu2L2Br 2 and Co2L2Cl4 complexes (L=3,5-dimethyl-1-thiocarboxamidepyrazole) is described. The influence of the central ion to ligand mole ratio on the course of complex formation is examined in reaction of L with copper(II) chloride. In Cu(II):L mole ratio of 1:1, in methanolic solution the reaction yields to yellow-green Cu2L 2Cl4 crystals. In the filtrate a thermodynamically more stable orange Cu2L2Cl2 copper(I) complex is forming. With a Cu(II):L mole ratio of 1:2 only the latter compound is obtained. The composition and the structure of the compounds have been determined on the basis of customary methods. On the basis of FTIR spectrum of the intermediate which is forming during the thermal decomposition of Cu2L 2Cl2 a decomposition mechanism is proposed. © 2006 Akadémiai Kiadó, Budapest.