Spectrochemistry of solutions. Part 19. Complexation of gold(I) by cyanide in liquid ammonia: an infrared and Raman spectroscopic study

Abstract

Complexation of Au^I by CN^– in liquid ammonia is different from Ag^I with which a large number of complexes and ion pairs occur. Like the aqueous system, ligation passes through AuCN and stops at the linear species [Au(CN)₂]^–. Frequencies in the i.r. and Raman spectra of these species in ammonia solution have been assigned. Raman spectra of the solution with [CN^–]/[Au^I]= 1 between 220 and 300 K indicate that both the free energy and entropy changes of the second complexation step are low, pointing to the existence of AuCN in ammonia as linear (H₃N)Au(CN).