Distinctive chemo- and stereo-selective reactions of [Fe(CO) 2Cp] + and [AuPPh 3+ with the anionic thioketene complex, [W(CO) 5&[;C(OEt)(Ph)C(Ph)=C=S&];] −. Crystal structures of Z-[W(CO) 5&[;C(SFe[CO] 2Cp)C(Ph)=C(OEt)Ph&];] and E-[W(CO) 5&[;S=C(AuPPh 3)C(Ph)=C(OEt)Ph&];

Abstract

Reaction of the unusual thioketone adduct [W(CO) 5&[;C(OEt)(Ph)C(Ph)=C=S&];]Li with [Fe(CO) 2CpI] gives two binuclear tungsten iron complex isomers of composition [W(CO) 5&[;C(SFe[CO] 2Cp)C(Ph)=C(OEt)Ph&];] that differ only in the position of the iron substituent at the extremely short C(carbene)S bond. Crystallization affords only the isomer in which the metal atoms are oriented trans, as is shown by the X-ray crystal structure. Both isomers have a Z configuration about the C=C double bond. Treatment of the same adduct with [AuC/PPh 3] affords a binuclear compound in which the tungsten and gold atoms are linked by a thione group. This conversion is also stereo-selective with regard to the alkene bond and only the E isomer is formed. The structure of the product [W(CO) 5&[;S=C(AuPPh 3)C(Ph)=C(OEt)(Ph)&];] was determined by X-ray diffraction. Comparison of structural features with the related thioaldehyde complex, E-[W(CO) 5&[;S=CHC(Ph)=C(Ph)(OEt)&];] reveals the significant electron-withdrawing effect of the gold fragment.