Synthesis, characterization and crystal structure of new copper(II) complexes with tris- and tetrakis-(pyrazol-1-yl)borate ligands

The synthesis and characterization of six new copper(II) complexes [HnB(pz)(4-n)](2)Cu (pzH=3-methyl- or 4-methyl-pyrazole, n = 1 or 0; pzH = 3,5-dimethyl-4-chloropyrazole or 3,4,5-trimethyl pyrazole, n = 1) are reported. X-ray cry stal structure studies were performed for [HB(3-Mepz)(3)](2)Cu, [HB(4-Mepz)(3)](2)Cu, [HB(3,5-Me-2-4-Clpz)(3)](2)Cu, and [B(3-Mepz)(4)](2)Cu, all of which are in a strongly distorted octahedral environment. Some derivatives were also characterized with fast atom bombardment spectrometry and magnetic susceptibility measurements. (C) 1999 Elsevier Science Ltd. All rights reserved.