Copper(II/I) complexes of a bulky tris(pyrazolylmethyl)amine ligand

The ligand tris[3-(4-methoxyphenyl)-5-methylpyrazol-1-ylmethyl]amine (L), t he copper(II) complexes [CuLCl2] 1, [CuLCl][SbF6] 2 and [CuL(H2O)][SbF6](2) 3, and the copper(I) complex [CuL][CF3SO3] 4 have been prepared. Complexes 1-3 are reduced by [BPh4](-) ion in a range of solvents to afford [CuL](+) ion. The [CuL](+) ion does not react with dioxygen nor carbon monoxide but does react with chloride ion. Physicochemical and cyclic voltammetry data are reported for 1-4, along with crystal structure analyses of 1-3 and [CuL ][CuCl2]. There are some notable differences between the structures and pro perties of these copper complexes and those reported for analogues with pyr idyl- or imidazolyl amine ligands.