Bonding in d¹⁰ transition metal complexes. III. Infrared, Raman and N.Q.R. studies of some trimethylphosphine sulphide and trimethylarsine sulphide copper(I) complexes

Abstract

The infrared, Raman and n.q.r. (⁶³Cu, ⁶⁵Cu) spectra of tris(trimethylphosphine sulphide)copper(I) perchlorate, [Cu(Me₃PS)₃] ClO₄, cyclo-tris-μ(trimethylphosphine sulphide)-tri(chlorocopper(I)), (Me₃PSCuCl)₃, the trimethylarsine sulphide compounds [Cu(Me₃AsS)₃] ClO₄, (Me₃AsSCuCl)_n (n = an integer), and the bromo and iodo compounds (Me₃PSCuBr)_n, (Me₃PSCuI)_n have been studied with the aim of finding out more about the structure and bonding in these complexes. The infrared and Raman spectra indicate that the trimethylarsine sulphide compounds are probably isostructural with the corresponding trimethylphosphine sulphide compounds. The origin of the electric field gradient responsible for the copper nuclear quadrupole coupling in these compounds is discussed, and it is shown that the copper n.q.r. results can be explained in terms of a bonding scheme involving 3d-4s orbital mixing.