Specific Photochemical Dehydrocoupling of N-Heterocyclic Phosphanes and Their Use in the Photocatalytic Generation of Dihydrogen

摘要

N-Heterocyclic phosphanes react under UV irradiation in a highly selective dehydrocoupling reaction to diphosphanes and H-2. Computational studies suggest that the product formation is initiated by the formation of dimeric molecular associates whose electronic excitation yields H-2 and a diphosphane. Combining the dehydrocoupling of sterically demanding phosphanes with Mg-reduction of the formed diphosphanes allows constructing a reaction cycle for the photocatalytic reductive generation of H-2 from Et3NH+.