Synthesis and reactivity of labile MeCN adducts of diruthenium bis(mu-methylene) species, Cp2Ru2(mu-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

Irradiation of the diruthenium bis(mu-methylene) complex Cp2Ru2(mu-CH2)(2)(CO)(2) (1), in acetonitrile gives the mono- and bis(acetonitrile) species Cp2Ru2(mu-CH2)(2)(CO)(MeCN) (2) and Cp2Ru2(mu-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-mu-methylene complexes, Cp2Ru2(mu-CH2)(2)(H)(mR(3))(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 mu-methylene-mu-silylene complexes, Cp2Ru2(mu-CH2)(mu-SiR2)(H)(SiR3)(CO) (8), and a tristannyl-mu-methylene complex, Cp2Ru2(mu-CH2)(mu-H)(SnPh3)(3)(CO) (10). Treatment of 2 with alkynes ((RC)-C-1 drop CR2) and diphenyldiazomethane produces the metallacyclic products Cp2Ru2[mu-eta(3)-C(R-1)C(R-2)=CH2](mu-CH2) (CO) (12), and the vinylidene complex Cp2Ru2(mu-C=CPh2)(mu-eta(3)-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.