Coupling of acetylene molecules on ruthenium clusters, involving cleavage of C-Si bonds in the alkyne and coordination of a phenyl ring of a SiPh _3 group

摘要

The reaction of [Ru_3(CO)_(12)] with the disubstituted acetylene Me_3SiCCSiMe_3 yields several compounds where cleavage of the C-Si bond has occurred thus allowing an easy coupling of carbon fragments to produce allene complexes [Ru_4(CO) _(12)(μ_4-η~3-Me_3SiCCCSiMe _3)] (2), differently substituted metallacycle compounds [Ru _3(μ_2-CO)_2(CO)_6{μ_3- C(R)C(SiMe_3)C(R′)C(SiMe_3)}] (3) [R = SiMe _3, R′ = CH_3 (3a); R = H, R′ = CH_3 (3b); R = CCSiMe_3; R′ = H (3c)] and a pentanuclear ruthenium cluster containing three separate alkyne units; two with one SiMe_3 substituent and one with two SiMe_3 substituents, coordinated to the metal framework [Ru_5(CO)_(12){μ_3-(C _2SiMe_3)_2}μ_2-C _2(SiMe_3)_2] (4). Another product of the reaction is the acetylide derivative [(μ-H)Ru_3(CO)_9(CCSiMe _3)] (1a). In order to determine if this was an intermediate for the formation of the products already mentioned, the reaction of this compound was carried out with the two terminal alkynes HCCSiMe_3 and HCCSiPh 3. In the case of the reaction with the SiMe_3 derivative, products included the same metallocyclopentadiene derivatives as well as the pentanuclear cluster already mentioned. If the acetylene is the SiPh_3 derivative, products show coupling of SiPh_3CC units with CCSiMe _3 fragments and CO molecules, coordinated to mononuclear [Ru(CO) _2(CCSiPh_3){η~5-(CCSiPh_3) _2C(OH)}] (7), dinuclear [Ru_2(CO)_3{Ph _3Si(H)CC(H)CC(SiMe_3)C(O)C(SiPh_3)C(H)}] (8) and trinuclear [Ru_3(CO)_4{(Ph_3Si(H)CC(H)CC(SiMe _3)}{(H)CC(SiPh_3)C(O)}] (9) clusters. One important characteristic in compounds 8 and 9 is that one of the phenyl rings of the SiPh_3 substituent is η~6 coordinated to a ruthenium atom. Compounds 2 to 4(a-c) and 7 to 9 were characterized spectroscopically and by X-ray diffraction.