OXIDATIVE ADDITION-REACTIONS OF 2,2'-BITHIOPHENE AND 2,2'/5',2''-TERTHIOPHENE WITH TRINUCLEAR CLUSTERS OF IRON, RUTHENIUM AND OSMIUM

Reactions of the cluster [Os3(CO)10(MeCN)2] With 2,2'-bithiophene (C8H6S2) and 2,2': 5',2''-terthiophene (C12H8S3) lead to the decacarbonyl complexes [Os3(mu-H)(C8H5S2)(CO)10] and [OS3(mu-H)(C12H7S3)(CO)10], respectively, which are formed by C-H bond cleavage. Upon heating these compounds, decarbonylation occurs to afford high yields of the corresponding nonacarbonyl species [OS3(A-H)2(C8H4S2)(CO)9] and [OS3(mu-H)2(C12H6S3)(CO)9]. In contrast, the reaction of 2,2'-bithiophene with [Ru3(CO)12] leads to the dimer [Ru2(C8H6S)(CO)6] by cleavage of the C-S bond and extrusion of the heteroatom. The cluster [Fe3(CO)12] reacts with 2,2'-bithiophene and 2,2':5',2''-terthiophene to give [Fe2(C8H6S2)](CO)6], [Fe2(C8H6S)(CO)6], [Fe2(C12H8S3)(CO)6] and [Fe2(C12H8S2)(CO)6] respectively, for which insertion of the metal atom in a C-S bond or extrusion of the heteroatom occurs.