Synthesis and Reactivity of Labile MeCN Adducts of Diruthenium Bis(μ-methylene) Species, Cp₂Ru₂(μ-CH₂)₂(CO)<i>_n</i>(MeCN)_2-<i>n</i>(<i>n</i>= 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 Cp 2 Ru 2 (μ-CH 2 ) 2 (CO) 2 ( 1 ), in acetonitrile gives the mono- and bis(acetonitrile) species Cp 2 Ru 2 (μ-CH 2 ) 2 (CO)(MeCN) ( 2 ) and Cp 2 Ru 2 (μ-CH 2 ) 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, Cp 2 Ru 2 (μ-CH 2 ) 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 μ-methylene−μ-silylene complexes, Cp 2 Ru 2 (μ-CH 2 )(μ-SiR 2 )(H)(SiR 3 )(CO) ( 8 ), and a tristannyl−μ-methylene complex, Cp 2 Ru 2 (μ-CH 2 )(μ-H)(SnPh 3 ) 3 (CO) ( 10 ). Treatment of 2 with alkynes (R 1 C⋮CR 2 ) and diphenyldiazomethane produces the metallacyclic products Cp 2 Ru 2 [μ-η 3 -C(R 1 )C(R 2 ) CH 2 ](μ-CH 2 )(CO) ( 12 ), and the vinylidene complex Cp 2 Ru 2 (μ-C CPh 2 )(μ-η 3 -CPh 2 ) ( 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.