Rhodium(III) and iridium(III) half-sandwich complexes with tertiary arsine and stibine ligands

Abstract

The syntheses of rhodium(III) and iridium(III) half sandwich complexes containing tertiary arsine and stibine ligands of the form [Cp*M(L)Cl2] (M = Rh, Ir; L = AsEt3, AsPh3, SbPh3) are reported. These compounds represent infrequent examples of rhodium and iridium metal complexes bearing arsenic or antimony ligands. All new compounds were fully characterised using 1H and 13C NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. DFT calculations show the formation of the complexes from (Cp*MCl2)2 and EPh3 (E = P, As, Sb) to be highly exothermic, although the enthalpic driving force is decreasing in the expected sequence P > As > Sb.