Reactions of [Et 3 NH][(μ‐CO)(μ‐RS)Fe 2 (CO) 6 ] with acetylenes. Synthesis of (μ‐σ,π‐ p ‐MeC 6 H 4 CCHPh)(μ‐RS)Fe 2 (CO) 6 and (μ‐σ,π‐PhCCHC 6 H 4 Me‐ p )(μ‐RS)Fe2(CO) 6 . The crystal structure of (μ‐σ,π‐ p ‐MeC 6 H 4 CCHPh)(μ‐ t BuS)Fe 2 (CO) 6

The reactions of [Et 3 NH][μ‐CO)(μ‐RS)Fe 2 (CO) 6 ] (1a‐d) (R n Pr, n Bu, t Bu, Ph) with p ‐MeC 6 H 4 C°CPh or m‐ NO 2 C 6 H 4 C°CPh were studied and products of the vinyl type (μ‐σ,π‐ p ‐MeC 5 H 4 CCHPh)(μ‐RS)Fe 2 (CO) 6 (2) and (μ‐σ, π‐phCCHC 6 H 4 Me‐ p ) (μ‐RS)Fe 2 (CO) 6 (3) (R n Pr, n Bu, t Bu, Ph) were obtained. While the structures of all the compounds 2a‐d and 3a‐d were characterized by elemental analysis, IR, 1 H NMR and MS spectroscopies, the single‐crystal structure of 2c(R t Bu) was determined by X‐ray diffraction method. The X‐ray diffraction result of 2c showed that the substituted vinyl ligand p ‐MeG 6 H 4 CCHPh bridges the two iron centers, being σ‐bonded to one metal through the olefinic carbon attached to p ‐MeC 6 H 4 4 group, while π‐bonded to the other via olefinic linkage; the Fe 2 (CO) 6 and proton units are in a cis fashion and the t Bu group is bonded to sulfur atom through an e‐type of bond.