Cyano-modified poly(triazine imide) with extended π-conjugation for photocatalytic biological cofactor regeneration

Abstract

Developing biological cofactor regeneration strategies is crucial for photo-enzyme coupling systems. Here, crystalline poly(triazine imide) (PTI) containing the cyano group (–CN) is designed for photocatalytic nicotinamide cofactor oxidation regeneration via π–π interaction. The π-conjugation degree and electron delocalization of PTI can be regulated through –CN modification. Such a unique extended π-conjugated system promotes the adsorption of the reduced-state nicotinamide cofactor (NADH) on the aromatic skeleton. Moreover, the enhanced charge transfer dynamics expedite the formation of intermediate active species. Accordingly, the optimized conversion rate of NADH to NAD⁺ reached 98.2% within 60 min. In contrast, pristine PTI and amorphous polymeric carbon nitride (PCN) gave oxidation yields of 88.1% and 56.8%, respectively. The exclusive selectivity of the oxidized product was further verified by the enzymatic method and nuclear magnetic resonance characterization. This study introduces an innovative method for modulating non-covalent interactions for photo-enzymatic catalysis via the extended π-conjugated system.