Rhodium complex-anchored and supramolecular polymer-grafted CdS nanoflower for enhanced photosynthesis of H_(2)O_(2) and photobiocatalytic C–H bond oxyfunctionalization

Unspecific peroxygenases exhibit high activity for the selective oxyfunctionalization of inert C(sp3)–H bonds using only H_(2)O_(2) as a clean oxidant,while also exhibiting sensitivity to H_(2)O_(2) concentration.CdS-based semiconductors are promising for the photosynthesis of H_(2)O_(2) owing to their adequately negative potential for oxygen reduction reaction via a proton-coupled electron transfer process,however,they suffer from fast H_(2)O_(2) decomposition on the surface of pristine CdS.Therefore,[Cp*Rh(bpy)H_(2)O]2+,a highly selective proton-coupled electron transfer catalyst,was anchored onto a supramolecular polymer-grafted CdS nanoflower to construct an efficient integrated photocatalyst for generating H_(2)O_(2),mitigating the surface issue of pristine CdS,increasing light absorption,accelerating photonic carrier separation,and enhancing oxygen reduction reaction selectivity to H_(2)O_(2).This photocatalyst promoted the light driven H_(2)O_(2) generation rate up to 1345μmol·L^(-1)·g^(-1)·h^(-1),which was 2.4 times that of pristine CdS.The constructed heterojunction photocatalyst could supply H_(2)O_(2) in situ for nonspecific peroxygenases to catalyze the C–H oxyfunctionalization of ethylbenzene,achieving a yield of 81%and an ee value of 99%under optimum conditions.A wide range of substrates were converted to the corresponding chiral alcohols using this photo-enzyme catalytic system,achieving the corresponding chiral alcohols in good yield(51%–88%)and excellent enantioselectivity(90%–99%ee).