Synthesis and Structural Characterization of Copper(I) Complexes with Hard Donor Ligands

Abstract: Syntheses and crystal structures of nine new copper(I) complexes and one novel mixed-valence copper(I/II) complex are reported: two homoleptic phenoxides and eight complexes with N-donor ligands.

The copper(I) and the copper(I/II) phenoxide complexes have been prepared by reactions between mesitylcopper(I) and 2-allyl-6-methylphenol in toluene. The copper ions in both compounds exhibit four-co-ordination, those in the tetrameric monovalent compound having distorted trigonal pyramidal geometry. The copper(I) atoms in the mixed-valence compound have distorted tetrahedral geometry and the copper(II) atom exhibits slightly distorted square planar geometry. The Cu(I) atoms are co-ordinated by both the oxygen and the allyl groups of the ligands. Cu(I)­O distances ranges from 1.973(6) Å to 2.577(6) Å.

The N-donor ligand complexes were prepared from CuCl or CuBr and the ligand in acetonitrile, THF or dichloromethane. Four of these complexes are co-ordination polymers, two are dimers, one is a tetranuclear complex and one is a discrete monomer. In the tetranuclear complex all four coppers exhibit different co-ordination geometries and in the other seven complexes they are tetrahedrally co-ordinated. Cu(I)­N distances ranges from 2.036(5) Å to 2.224(3) Å for the non-acetonitrile ligands. For co-ordinated acetonitrile the Cu(I)­N distances are from 1.950(3) Å to 1.985(3) Å.