Reactions of methyl(phenyl)silylene with CO and PH3—the formation of acid–base complexes

The thermal reaction of methyl(phenyl)silylene 1a with CO and PH3, respectively, was investigated using matrix isolation spectroscopy in combination with DFT calculations. The silylene 1a was produced by UV irradiation (λ>400 nm followed by λ>350 nm) of (phenyl)silyldiazomethane 2 in high yields. The thermal reaction of 2 with CO in CO-doped argon matrices produces the acid–base adduct 3 which was identified by IR and UV spectroscopy. The analogous reaction with PH3 produced the acid–base adduct 4. Complex 4 is photolabile and on irradiation with UV light (λ>350 nm) rearranges to methylphenyl(phosphino)silane 5, the product of the insertion of the silicon atom into a PH bond.