Highly selective regeneration of 1,4-NADH enabled by a metal-free core-shell photocatalyst of resorcinol-formaldehyde resins@polyaniline under visible light

Cofactors, including reduced nicotinamide adenine dinucleotide (NADH), are involved in approximately 80 % of oxidoreductase-catalyzed reactions. However, NADH has not been widely used in the industrial production processes due to cost factors. In this work, we have designed a kind of metal-free core-shell photocatalyst with resorcinol-formaldehyde resin spheres as the core and polyaniline as the shell (RF@PANI) for the highly efficient and selective photocatalytic regeneration of 1,4-NADH (only 1,4-NADH has enzyme activity). It was demonstrated that the introduction of the carbonyl group and the sum of electronic effects made the C4 site of NAD+ a more electrophilic hydride transfer site rather than C6 and C2 in the RF@PANI system, leading to the high selectivity of NAD+ to 1,4-NADH. The discovery of this mechanism will guide the design of more efficient and highly selective catalysts to break through the cost limitations for the large-scale applications of NADH.