In an Reactions of Triethylammonium Salts of the [ O 1 - CO ) ( / l - RS ) Fe 2 ( CO ) ~ ] - Anions with Alkynylmercury Compounds . Unexpected Products via Hydrogen Migration Processes ?

The reaction of [Et3NHI[@-CO)Cu-RS)Fe2(C0)6] with bis(1-alkyny1)mercw-y compounds gave different products depending on the nature of the organomercurial. Bis(phenylethyny1)mercury and bis( 1-hexyny1)mercury gave p-q1:q2-acetylide complexes, @-q1:q2-CsCR1)@-RS)Fe2(CO)6, while bis(3-methoxy-1-propyny1)mercury and bis(3-(dimethylamino)-l-propynyl)mercury formed doubly bridging vinylcarbyne products, Cu-XCH=CHC)@-RS)Fe2(CO)6, where X = OCH3, N(CH&. The vinylcarbyne products resulted from a net 1,2-hydrogen shift from the propargylic carbon atom to the ,&carbon atom of the original acetylenic unit. In addition, the reaction with bis(3-methoxy-1-propyny1)mercury gave a tetrairon cluster, [@-CH30CH2CHC)@-RS)Fe2(CO)6]2Hg, composed of two butterfly diiron hexacarbonyl moieties (each of which possessed doubly bridging vinylidene and thiolate ligands) bridged by a mercury atom on the butterfly hinges. X-ray crystal structure determinations were carried out on the vinyl carbyne complex (~-CH~OCH=CHC)@-~-BUS)F~~(CO)~ as well as the dimeric mercury product [@-CH~OCH~CH=C)@-~-BUS)F~Z(CO)~I~H~. The reactions of propargylic substituted 1-bromoalkynes also were dependent on the nature of the acetylene. 3-Methoxy-lbromopropyne formed the p-q1:q2-acetylide complex Cu-q1:q2-C~CCH2OCH3)@-t-BuS)Fe2(CO)6, as well as the doubly bridging vinylcarbyne product, while 3-dimethylamino-1-bromopropyne gave only the vinylcarbyne complex. The vinylcarbyne complex (ll-CH3OCH=CHC)@-t-BuS)Fez(C0)e was converted to the formyl-substituted p-q1:q2-vinyl complex @-q1:q2-CH=CHC(O)H)@-t-BuS)Fe2(CO)6 upon treatment with aqueous hydrochloric acid or trifluoroacetic acid.