Structure-Catalytic Activity in a Series of Push-Pull Dicyanopyrazine/Dicyanoimidazole Photoredox Catalysts

A series of dicyanopyrazine and dicyanoimidazole derived push-pull molecules have been prepared and further investigated as photoredox catalysts. The fundamental properties of the catalysts were studied by DSC, X-ray analysis, absorption/emission spectra, and electrochemistry and were completed with the DFT results. The catalytic activity has been evaluated in visible light induced alpha-functionalization of amines (cross-dehydrogenative coupling and annulation reaction of tetrahydroisoquinolines). Thorough structure-property-catalytic activity relationships were elucidated. The developed series of tailored organic photoredox catalysts allows synthetic chemists to perform desired reactions under sustainable and mild conditions employing solely visible light as a source of energy.