Copper(II) chloride/1-methylbenzotriazole chemistry: influence of various synthetic parameters on the product identity, structural and magnetic characterization, and quantum-chemical studies

A systematic investigation of the CuCl2/Mebta (Mebta = 1-methylbenzotriazole) reaction system is described. Several complexes were isolated, namely [Cu2Cl4(Mebta)4] (1), [CuCl2(Mebta)2] (2), {[Cu2Cl4(Mebta)2]}n (3), [Cu4OCl6(Mebta)4] · 0.25H2O (4 · 0.25H2O) and [Cu2Cl2(Mebta)6](ClO4)2 (5), which were structurally characterized by single-crystal X-ray crystallography and studied by spectroscopic methods. Their magnetic studies showed ferromagnetic interactions. A new magneto-structural criterion was developed, governing the magnetic exchange coupling in bis(μ-chloro) copper(II) dimers.