Clean and efficient transformation of co₂ to isocyanic acid: the important role of triatomic cation scnh⁺

Achieving the desired selective transformations of the very stable CO₂ into useful chemicals is quite important for the development of economically and environmentally sustainable synthetic methods. Herein, mass spectrometric experiments and quantum-chemical calculations have identified that ScNH⁺ reacts quite efficiently with CO₂ under thermal collision conditions to exclusively yield ScO⁺ and isocyanic acid (HNCO). This is a novel reaction type in CO₂ activation reactions mediated by gas-phase ions. In this reaction, the CâN double bond has also been formed for the first time in the gas phase. The mechanism of "migratory insertion" is proposed. Coupled with the previously reported reaction of Sc⁺ with NH₃, HNCO can be synthesized under mild conditions from NH₃ and CO₂ in quite simple reactions. The mechanistic information gained in this gas-phase model reaction can offer fundamental insights relevant to corresponding processes and further guide on how to design brand new catalysts.