Electron spin resonance evidence for the structure of AgII and AgO solvates in acetonitrile

Abstract

There are currently three quite disparate concepts concerning the structures of the solvates of Ag^II and Ag^O centres formed from solutions of Ag^I ions in acetonitrile. These are derived from e.s.r. and electron spin-echo modulation studies. We have now established that identical centres are formed from the crystalline derivative AgClO₄(MeCN)₄, whose crystal structure is known. Analysis of the e.s.r. spectra suggests that the original tetrahedral configuration with σ-bonded MeCN ligands is initially retained on electron addition, but that three of the four solvent molecules are lost on annealing or photolysis. Electron loss results in relaxation to give square planar coordination for the Ag^II centre, but the σ coordination is retained. We find no evidence for (π) coordination.