Bonding in dl0 transition metal complexes. I. Infrared, Raman, and N.Q.R. studies of some dihalocuprate(I) complexes

Abstract

The i.r. and Raman spectra of the dihalocuprate(1) ions CuX₂^- (X = Cl, Br) have been measured in solution, and in a number of crystalline compounds with large organic cations. The halogen and copper n.q.r. frequencies of the CuX₂^- ions in some of the solid complexes were also measured. In all cases, the ions were found to have linear, centrosymmetric structures. The various theories which have been proposed to describe the bonding in linear d¹⁰ transition metal complexes are discussed, and it is concluded that the scheme proposed by Orgel and Jorgensen, involving ds hybridization on the metal atom, best accounts for the n.q.r. results, although some uncertainty is introduced through the lack of sufficient information concerning the magnitude of the Sternheimer effect. An experiment which might differentiate between the ds and sp hybridization schemes in the case of linear Au^I complexes is proposed.