Gold(I) complexes with P=O and P-OH functionalised phosphorus ligands

P-coordination of anionic phosphonite [((RO)-O-2)(RPO)-P-1](-) or phosphite [(RO)(2)PO](-) ligands to (triorganophosphine)gold(I) units leads to neutr al molecules with an unsymmetrical P-Au-P' axis and a P=O function. A gener al synthetic route starts from (R3P)AuMe precursors and the corresponding p rimary phosphonites ((RO)-O-2)(RP)-P-1(O)H or secondary phosphites (RO)(2)P (O)H, respectively. The gold(I) phosphonites (R3P)AuP(O)R-1(OR2) (1a-d) und ergo a ligand redistribution in solution, establishing equilibria that invo lve ionic isomers of the type [(R3P)(2)Au](+)[Au{P(O)R-1(OR2)}(2)](-) as de monstrated by NMR spectroscopy. In the complexes Ph2P(OH)AuCl (2), Ph2P(OH) AuGeCl3 (3), [Ph2P(OH)](2)Au+X-, with X- = ClO4- (4a), SbF6- (4b), BF4- (4c ), TfO- (4d) and (MeO)(2)P(OH)AuCl (5) the phosphinous acid and the phospho rous acid diester, respectively, are coordinated to gold(I) as neutral liga nds with a P-OH function, respectively. The combination of the anionic phos phite and neutral ester ligands in the same molecule leads to the formation of compounds [(RO)(2)P(OH)AuP(O)(OR)(2)](n) (6a-c), which oligomerise via cooperative action of hydrogen and aurophilic bonding as determined by sing le-crystal X-ray diffraction and NMR measurements. The degree of oligomeris ation depends largely on the steric effect of the R groups. Compound 6b is a dimer, while compound 6a is a polymer. The crystal structure of the phosp hite complex [(Me3P)AuP(O)(OMe)(2)](n). (7) contains a chain of neutral mon omeric units associated solely via aurophilic contacts. (C) 2000 Elsevier S cience S.A. All rights reserved.