Synthesis and structural characterization of gold-(I), -(III) and silver(I) complexes of the ylide ligand Ph3PCHC(O)NMe2. Crystal structure of [(AuPPh3)2{µ-C(PPh3)C(O)NMe2}]ClO4

Abstract

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.