Gold(I) and Gold(III) complexes of the [CH(dppm)2]+ and C(dppm)2 PCP pincer ligand systems

Abstract

Gold(III) complexes of the PCP pincer carbodiphosphorane (CDP) ligand C(dppm)2 and gold(I) complexes of the conjugate CH acid [CH(dppm)2]+ were synthesized and characterized by single crystal diffraction and by NMR spectroscopy. The gold(I) complex [AuCl(CH(dppm)2)-κ2P,P′]Cl (1) exhibits an approximate trigonal planar AuClP2 core, whereas the gold center in the [Au(CH(dppm)2)-κ2P,P′)](TfO)2 complex (2) is only two-coordinated (P(1)-Au(1)-P(4) around 167.3°). Both complexes show no significant interaction between the gold(I) and the CDP carbon and consequently, an eight membered chelate ring is observed. [AuI(C(dppm)2)-κ3P,C,P′)](TfO)2 (3) and [AuCl(C(dppm)2)-κ3P,C,P′)](NO3)2 (4) were obtained via oxidation of complex 1 or 2 with iodine or nitric acid, respectively. The gold(III) center is stabilized in a square planar coordination geometry by two dppm units, the divalent carbon(0) atom of the C(dppm)2 ligand system, and a halide ion.