Reactivity of bridging thiocarbyne complexes of iron

The thiocarbyne cations, Cp(,2)Fe(,2)(CO)(,2)((mu)-CO)((mu)-CSR)('+) (R = Me, Bz, All), react with a variety of nucleophiles (Nuc = H('-), MeS('-), PHS('-), BzS('-), PhSe('-) and BzMgCl) to give bridging carbene complexes, Cp(,2)Fe(,2)(CO)(,2)((mu)-CO) (mu)-C(SR)Nuc . The cis-syn isomers of (mu)-hydridothiocarbene complexes, Cp(,2)Fe(,2)(CO)(,2)((mu)-CO) (mu)-C(H)SMe and Cp(,2)Fe(,2)(CO)(,2)((mu)-CO) (mu)-C(H)SCH(,2)Ph , have been isolated. In CDCl(,3), these complexes undergo a slow cis-syn to cis-anti interconversion and an even slower cis-syn/trans-syn isomerization. Solutions (in benzene, CHCl(,3), CH(,2)Cl(,2), acetone, and CH(,3)CN) of (mu)-dithiocarbene complexes, Cp(,2)Fe(,2)(CO)(,2)((mu)-CO) (mu)-C(SMe)SR , are equilibrium mixtures of all possible cis and trans isomers. The initially formed (mu)-selenothiocarbene complex, Cp(,2)Fe(,2)(CO)(,2)((mu)-CO) (mu)-C(SMe)SePh , converts to a (mu)-carbyne complex, Cp(,2)Fe(,2)(SePh)(CO)((mu)-CO)((mu)-CSMe), at 0(DEGREES)C. In contrast, the (mu)-dithiocarbene complex, Cp(,2)Fe(,2)(CO)(,2)((mu)-CO) (mu)-C(SMe)SPh , converts to Cp(,2)Fe(,2)(SPh)(CO)((mu)-CO)((mu)-CSMe) at 40(DEGREES)C;Reaction of Cp(,2)Fe(,2)(CO)(,2)((mu)-CO)((mu)-CSMe)('+) with primary and secondary amines gives presumably the unstable complexes, CP(,2)Fe(,2)(SMe)(CO)((mu)-CO)((mu)-CNR(,2)). Tertiary amines do not react;A one electron reduction of Cp(,2)Fe(,2)(CO)(,2)((mu)-CO)((mu)-CSMe)('+) gives the deep emerald green radical, Cp(,2)Fe(,2)(CO)(,2)((mu)-CO)((mu)-CSMe)(.), which has been characterized by IR, EPR and UV-visible spectroscopy. Ligand exchange reactions of Cp(,2)Fe(,2)(CO)(,2)((mu)-CO)((mu)-CSMe)('+) are catalyzed by the radical, and apparently proceed through a mechanism involving dissociative loss of CO from Cp(,2)Fe(,2)(CO)(,2)((mu)-CO)((mu)-CSMe)(.);Reaction of Na Co(CO)(,4) with Cp(,2)Fe(,2)(CO)(,2)((mu)-CO)((mu)-CSMe)('+) under UV photolysis gives Cp(,2)Fe(,2)Co(CO)(,3)((mu)-CO)(,2)((mu)(,3)-CSMe). An x-ray diffraction study of this cluster shows that it has an L-shaped triangular structure, but there is no Co-Fe bond on one edge of the triangle. The CSMe group bonds through the carbyne carbon to all three metals, and in addition the sulfur coordinates to the cobalt atom.