Quinazo[3,4,5,6-ija]quinoline Derivatives: Synthesis and Application in Photocatalytic Hydrogen Evolution From Water

A series of 4,5,9,10-tetraaryl-quinazinoquinoline derivatives were synthesized and applied to hydrogen evolution in water splitting as photosensitizers. In this photocatalytic water reduction system, PdCl2 is the most suitable water reduction catalyst and the reduction quenching is the main quench way for the excited photosensitizers. The substituent effect could explain the structure-activity relationship in photocatalytic water reduction system. The methoxy group as an electron donating substituent was found to increase the turnover number for hydrogen production (TON) of the derivatives up to 341. Photophysical and electronic chemical characterization of quinazinoquinoline derivatives showed that the methoxy group could increase the fluorescence quantum efficiency of the derivatives up to 0.48.