Understanding the Reactivity Difference of Isocyanate and Isothiocyanate toward a Ruthenium Silylene Hydride Complex

The detailed reaction mechanisms of the CO hydrosilylation of isocyanate and the CS bond cleavage of isothiocyanate mediated by the neutral ruthenium silylene hydride complex Cp*­(CO)­(H)­RuSi­(H)­{C­(SiMe3)3} have been investigated with the aid of density functional theory calculations. Through the investigation, the difference in reactivity between isocyanate and isothiocyanate toward the ruthenium silylene hydride complex has been examined and discussed. The different bond strengths and π-accepting abilities of CO and CS and the different degrees of affinity of O and S toward the Si center in the silylene ligand contribute to the different reactivities of the isocyanate and isothiocyanate substrates observed experimentally.