Synthesis and structural characterization of gold-( I ), -( III ) and silver( I ) complexes of the ylide ligand Ph 3 PCHC(O)NMe 2 . Crystal structure of [(AuPPh 3 ) 2 {µ-C(PPh 3 )C(O)NMe 2 }]ClO 4

The reaction between [AuCl(tht)](tht = tetrahydrothiophene) and the ylide Ph3PCHC(O)NMe2 gives [AuCl{CH(PPh3)C(O)NMe2}]1, which reacts with chlorine to gives [AuCl3{CH(PPh3)C(O)NMe2}]2 and with the same ylide and NaClO4 to form [Au{CH(PPh3)C(O)NMe2}2]ClO43. The analogous silver complex [Ag{CH(PPh3)C(O)NMe2}2]ClO44 is obtained by the reaction of AgClO4 with the ylide in molar ratio 1 : 2. The phosphonium salt [Ph3PCH2C(O)NMe2]ClO4 reacts with [Au(acac)(PPh3)](acac = acetylacetonate) to gives [Au{CH(PPh3)C(O)NMe2}(PPh3)]ClO45 or [(AuPPh3)2{µ-C(PPh3)C(O)NMe2}]ClO46 depending on the reaction conditions. The structure of 6 was confirmed by an X-ray diffraction study at –95 °C [space group P, a= 11.572(3), b= 11.836(3), c= 21.627(7)Å, α= 78.29(2), β= 87.19(2), γ= 75.65(2)°, R= 0.076]; the Au ⋯ Au bond length is 2.938(1)Å.