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The reaction of compounds (R3P)AuMe with diphenylphosphinous acid Ph,P(O)H affords methane and neutral complexes of the type (R,P)AuP(0)Ph2 (la: R = Me; lb: R = Ph; lc: R = o-Tol). l a , b are obtained in high yield, but the yield of l c is lower owing to a side-reaction which leads to a different product: Ph,P(OH)-Au-P(O)Ph, ( 2 ) . The crystal structure of l a was determined by a single-crystal X-ray diffraction study. The compound is a monomer with a linear P-Au-P' axis and the phosphane and phosphinite ligands in a staggered conformation. In solution (CHCl,, CH,Cl,) compounds la-c undergo a ligand redistribution, establishing equilibria that involve ionic isomers of the type [(R:3P)2Au]+ [Au-(P(O)Ph,),]-, which are readily identified through their NMR data. The analogous reaction of (R,P)AuMe with dimethylphosphite (MeO),P(O)H gives methane and the corresponding dimethylphosphites of the type (R,P)AuP(O)(OMe), (3a: R = Me; 3b: R = Ph; 3c: R = 0-Tol). The crystal structure of 3b has also been determined. It features a linear structure with an eclipsed conformation of the ligands. In polar solvents (CHCl,, methanol) there is again an equilibrium between neutral and ionic isomers, the latter comprising bis(phosphane)gold cations [(R,P),Au]+ and (Au[P(O)-(OMe),],)~-anions, as confirmed by NMR spectroscopy and mass spectronietry.

Diphenyl(2-hydroxy-phenyl)phosphine was introduced as a ligand for gold(I) halides and pentafluorophenyl gold(I) in order to probe the interplay of intra-and intermolecular interactions based on aurophilic (Au-• -Au) and hydrogen bonding. 1:1 complexes of the type Ph:(2-HO-CftH^P-Au-X with X = Cl, Br, C6F5 have been prepared and characterized by analytical and spectroscopic data. The crystal structure of the chloro complex (1) has been determined. In the lattice the molecules form dimers through O-H • Cl hydrogen bonds. Au-• Au contacts are ruled out by steric congestion. Reaction of 1 with triethylamine yields a 1:1 adduct with O-H • -NEt, hydrogen bonding. The trimethylsilyl ether of the title ligand also forms 1:1 complexes with AuCl, AuBr, Aul, and AuC6F5. The crystal structures of the chloro (5) and iodo (7) compound have been determined. In both cases the lattices are built from monomers which show only minor differences in their conformations. The silylether groups are not acting as intra-or intermolecular donor functions to the gold atoms.