Reactions of [Et3NH][(.mu.-CO)(.mu.-RS)Fe2(CO)6] complexes with acetylenes. Synthesis and decarbonylation of .alpha.,.beta.-unsaturated bridging acyl complexes

Reaction of [Et 3 NH] [(μ-CO) (μ-RS)Fe 2 (CO) 6 ] with alkyl- and arylacetylenes (R 1 C≡CR 2 ) produced neutral μ-vinyl complexes of the type (μ-σ, π-R 1 C=CHR 2 ) (μ-RS)Fe 2 (CO) 6 . Presumably, formation of these products resulted from the in situ protonation of an intermediate vinylic anion by the triethylammonium cation. 1 H NMR correlations have shown that overall addition of the diiron and proton units has occurred in a cis fashion