Hydrogenation and dehydrogenation reactions of the phenalenyl radical/1H-phenalene system at low temperatures

Abstract

Phenalenyl radical was generated in situ in inert matrices by laser UV photolysis of 1H-phenalene, and was identified by recording laser induced fluorescence and IR spectra. Theoretical computations predict that the H atom addition to phenalenyl radical is barrierless, while the H atom abstraction from 1H-phenalene has only a small barrier. Upon annealing the Xe matrix after the photolysis, the radical and the H atom recombine, while H atom abstraction from 1H-phenalene is a possible explanation for additional spectral changes. These results show that the phenalenyl radical/1H-phenalene system can be a very effective catalyst in the formation of interstellar H2.