Bonding in d¹⁰ transition metal complexes. II. Infrared, Raman, and N.Q.R. studies of some iodocuprate(I) complexes

Abstract

The infrared and Raman spectra of a number of iodocuprate(I) complexes have been studied. None of the solid complexes studied appears to contain the discrete diiodocuprate(I), CuI₂^-, or triiododicuprate(I), Cu₂I₃^-, ions which have previously been reported in solution studies, but bright yellow compounds which may contain the hexaiodotetracuprate(I) ion, Cu₄I₆^2-, have been prepared with methyltriphenylphosphonium and methyltriphenylarsonium cations. A structure based on a tetrahedron is proposed for the Cu₄I₆^2- ion, the copper atoms lying at the corners, and the iodine atoms bridging the copper atoms and lying along the edges of the tetrahedron. The evidence for this structure, and the information concerning the bonding in the ion obtainable from the vibrational and n.q.r. (⁶³Cu, ⁶⁵Cu, ¹²⁷I) spectra are discussed.