Synthesis and Reactivity of Labile MeCN Adducts of Diruthenium Bis(μ-methylene) Species, Cp2Ru2(μ-CH2)2(CO)n(MeCN)2-n(n= 1, 2): Reaction with H Sources, H−X (X = SiR3, SnR3, H), and C−C Coupling with Alkynes and Diazoalkanes

Abstract

Irradiation of the diruthenium bis(μ-methylene) complex Cp2Ru2(μ-CH2)2(CO)2 (1), in acetonitrile gives the mono- and bis(acetonitrile) species Cp2Ru2(μ-CH2)2(CO)(MeCN) (2) and Cp2Ru2(μ-CH2)2(MeCN)2 (3) in a successive manner. The mono-MeCN species 2 has been characterized spectroscopically and crystallographically, but the bis-MeCN species 3 is too unstable to be fully characterized. Reaction of 2 with hydrosilanes and hydrostannanes results in oxidative addition of the H−Si and H−Sn bond to give hydrido−μ-methylene complexes, Cp2Ru2(μ-CH2)2(H)(mR3)(CO) (m = Si (7), Sn (9)). In the case of the reactions with dihydrosilane, phenylsilane, and triphenylstannane, one of the two methylene bridges is eliminated as methane (and benzene from phenylsilane) to give μ-methylene−μ-silylene complexes, Cp2Ru2(μ-CH2)(μ-SiR2)(H)(SiR3)(CO) (8), and a tristannyl−μ-methylene complex, Cp2Ru2(μ-CH2)(μ-H)(SnPh3)3(CO) (10). Treatment of 2 with alkynes (R1C⋮CR2) and diphenyldiazomethane produces the metallacyclic products Cp2Ru2[μ-η3-C(R1)C(R2)CH2](μ-CH2)(CO) (12), and the vinylidene complex Cp2Ru2(μ-CCPh2)(μ-η3-CPh2) (14), respectively, via C−C coupling. In contrast to 2, corresponding reactions of the bis-MeCN species 3 are sluggish and only the simple MeCN replacement reaction proceeds in a selective manner.