Highly efficient photocatalytic dehydrogenative coupling of amines with supported platinum catalyst under the oxidant-free conditions

Abstract

A highly efficient photocatalytic dehydrogenative coupling (PDC) of amines to prepare value-added imines has been developed under the mild conditions. A complete conversion of benzylamine with a 99% selectivity of N-benzylidenebenzylamine could be obtained using the 2%Pt@g-C3N4 as photocatalyst in the absence of hydrogen acceptor at room temperature. Moreover, the relationship between the physical properties of different photocatalysts and their activities has been discussed according to the characterization results of the XRD, BET, SEM, TEM, and XPS techniques. Next, the PDC of different amines have been further investigated, where ca. 70.2%–99.0% yields of corresponding imines were attained. Finally, based on the experimental results and heterogeneous catalytic principle, a possible reaction mechanism for the PDC of benzylamine is proposed.