Hydrazone-linked DNP-functionalized PLA photocatalyst for sustainable HAT-mediated hydroalkylation and NADH-assisted enzymatic CO2-to-C1 fuel conversion

Abstract

This work presents a novel hybrid photocatalyst synthesized by integrating 2,4-dinitrophenylhydrazine (DNP) with poly(lactic acid) (PLA), yielding a hydrazone-linked DNPHz–PLA that combines photochemical reactivity with biocompatibility. Comprehensive characterization (AFM, TEM, DSC) confirmed uniform incorporation of DNP, nanoscale texturing, and thermal stability, establishing the material's suitability for light-driven redox applications. Under visible light, DNPHz–PLA drives SET/HAT-mediated radical hydroalkylation of electron-deficient alkenes with up to 85% yields and high regioselectivity, offering a mild, tin-free alternative to classical Giese chemistry for access to pharmaceutically relevant C(sp³)–C(sp²) frameworks. Crucially, DNPHz–PLA demonstrates efficient visible-light-driven NADH regeneration (73.8%), providing a renewable solar-derived reducing equivalent. Coupling regenerated NADH with formate dehydrogenase (FDH) enables enzymatic CO₂ capture and conversion to formic acid (180.61 μmol), a key C₁ fuel and hydrogen-storage intermediate. Collectively, this work establishes DNPHz–PLA as a versatile photohybrid platform bridging synthetic radical chemistry and bioreductive CO₂ valorization offering a scalable approach for light-driven chemical and environmental transformations.