Matrix isolation infrared spectroscopic and density functional theoretical study of the reactions of transition metal monoxide (ScO and TiO) with acetylene

The reactions of scandium and titanium monoxide molecules (ScO and TiO) with acetylene have been studied in solid argon with infrared absorption spectroscopy. The monoxide molecules were prepared by laser-evaporation of bulk oxide targets. The ground state scandium and titanium monoxide molecules reacted with acetylene to form the OSc-(η2-C2H2) and OTi-(η2-C2H2) molecules spontaneously on annealing, which were identified on the basis of isotopic IR studies with 13C2H2 and C2D2, as well as density functional calculations. The results imply that while the OSc-(η2-C2H2) adduct is a typical π complex, the OTi-(η2-C2H2) molecule should be considered as a titanacyclopropenone.