Ruthenium-99 Mössbauer spectra of some nitrosylruthenium(II) compounds

Abstract

⁹⁹ Ru Mössbauer spectra have been obtained at 4·2 K for a series of octahedral nitrosylruthenium(II) complexes [RuL₅(NO)]^n±. The chemical isomer shift decreases steadily as the ligand-field strength of L decreases (CN^– > NH₃ > NCS^– > Cl^– > Br^–), implying a positive sign for δR/R for ⁹⁹Ru. Changes in quadrupole splitting are also observed along the series and these are discussed in terms of the relative σ-donor and π-acceptor abilities of the ligands.