Synthesis, spectroscopic and structural characterization of Cu(II) derivatives of tris(pyrazol-1-yl)methanes

The reaction between CuX2 (X=ClO4, NO3, Cl, Br and CH3COO) and excess of tris(pyrazol-1-yl)methane ligands L (L=CH(pz)3, CH(4-Mepz)3, CH(3,5-Me2pz)3, CH(3,4,5-Me3pz)3 or CH(3-Mepz)2(5-Mepz)) yields [CuX2(L)], [{CuX2}3(L2)2] or [Cu(L2)]X2-type complexes. The ligand to metal ratio is dependent on the number and disposition of the Me substituents on the azole-type ligand and mainly on the nature of the counter-ion X. All complexes have been characterized in the solid state as well as in solution (IR and UV spectra, and conductivity determinations). The solid-state structures of [Cu{(3,5-Me2pz)3CH}2](NO3)2, [Cu{(3,5-Me2pz)3CH}2](ClO4)2·0.5H2O, [Cu{(3,4,5-Me3pz)3CH}2](NO3)2·H2O, [Cu{(4-Mepz)3CH}2]Br2·3H2O have been determined by single crystal X-ray studies.