Reactions of [H2OS3(CO)(10)] with conjugated diynes (RC2C2R ') containing nucleophilic oxygen in beta position of a substituent (R = Ph, R ' = CH2OH, C(O)Ph; R = R ' = CMe2(OH))

Reactions of [H2Os3(CO)10] with a series of diynes, RC2C2R' (1: R = Ph, R' = CH2OH; 2: R = Ph, R' = C(O)Ph; 3: R = R' = C(OH)Me2), have been studied. It was found that upon coordination to the triosmium cluster, the nucleophilic oxygens of the R' substituents of 1 and 2 take part in intramolecular cyclization reactions to give [HOs3(CO)10{-1:2-PhCH2(C=CH-C=CH-O)}] (5) and [HOs3(CO)10{-1:1-Ph(C=CH-C=C-O)CPh}] (6), respectively, both of which contain furan rings coordinated to the cluster core. On heating of the latter compound, the furan moiety remains intact, but a carbonyl group dissociates from the cluster, leading to the formation of [HOs3(CO)9(3-1:3:1-Ph(C=CH-C=C-O)CPh)] (7) with a closed "C3Os3" pentagonal pyramidal structure. Reaction of [H2Os3(CO)10] with 3 does not lead to cyclization of the diyne; instead, the clusters [Os3(CO)10{3-2-(RCH=CH-C2R)}] (8) and [Os3(CO)10{3-2-(RC2C2R)}] (9) are formed. Deuterium labeling of the starting compounds has been used in the reaction of [H2Os3(CO)10] with HOCH2C2C2CH2OH in order to investigate possible mechanisms of the cyclization reaction. The crystal and molecular structures of clusters 5, 7, and 9 are presented.