Copper(II) bromide/1-methylbenzotriazole chemistry - Variation of product as a function of solvent and ligand-to-metal reaction ratio

A systematic investigation of the CuBr2/Mebta (Mebta = 1-methylbenzotriazol e) reaction system is described. Particular emphasis has been placed on det ermining the influence of the Mebta:Cu-11 ratio and the nature of solvent o n the identity of the reaction products. These combined variations have led to the preparation of the following complexes; [CuBr2(Mebta)](n) (1), [CuB r2(Mebta)(2)(MeCN)]. MeCN (2), [CuBr2(Mebta)(2)] (3) and [CuBr2(Mebta)(3)]. 0.25H(2)O (4). Complexes 2, 3 and 4 have been structurally characterized b y single crystal X-ray studies. Mebta behaves as a monodentate ligand bindi ng through N(3). The geometry about copper(n) in 3 is tetrahedrally distort ed trans square planar, while complexes 2 and 4 have distorted trigonal bip yramidal stereochemistries. The new complexes were characterized by element al analyses, magnetic susceptibilities at room temperature and spectroscopi c (IR, far-IR, UV/VIS) techniques. A doubly bromo-bridged chain structure w ith two alternating chromophores is assigned for 1. All data are discussed in terms of the nature of bonding and known or assigned structures. A compa rison of the CuBr2/Mebta and CuCl2/Mebta systems is also presented. (C) 199 9 Elsevier Science Ltd. All rights reserved.