Synthesis and spectroscopy of cis-configured mononuclear palladium(II) and platinum(II) complexes of chalcogeno o-carboranes and structures of [Pt(SCb oPh) 2(dppm)], [Pt(SeCb oPh) 2(dppm)], [Pt(SCb oS)(PMe 2Ph) 2] and [Pt(SCb oS)(PMePh 2) 2

Abstract

The reactions of [MCl 2(P ∩P)] and [MCl 2(PR 3) 2)] with 1-mercapto-2-phenyl- o-carborane/NaSeCb oPh and 1,2-dimercapto- o-carborane yield mononuclear complexes of composition, [M(SCb oPh) 2(P ∩P)], [M(SeCb oPh) 2(P ∩P)] (M = Pd or Pt; P ∩P = dppm (bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)ethane) or dppp (1,3-bis(diphenylphosphino)propane)) and [M(SCb oS)(PR 3) 2] (2PR 3 = dppm, dppe, 2PEt 3, 2PMe 2Ph, 2PMePh 2 or 2PPh 3). These complexes have been characterized by elemental analysis and NMR ( 1H, 31P, 77Se and 195Pt) spectroscopy. The 1J(Pt–P) values and 195Pt NMR chemical shifts are influenced by the nature of phosphine as well as thiolate ligand. Molecular structures of [Pt(SCb oPh) 2(dppm)], [Pt(SeCb oPh) 2(dppm)], [Pt(SCb oS)(PMe 2Ph) 2] and [Pt(SCb oS)(PMePh 2) 2] have been established by single crystal X-ray structural analyses. The platinum atom in all these complexes acquires a distorted square planar configuration defined by two cis-bound phosphine ligands and two chalcogenolate groups. The carborane rings are mutually anti in [Pt(SCb oPh) 2(dppm)] and [Pt(SeCb oPh) 2(dppm)].