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.