Pyrimidine-Mediated Electronic Modulation of Ionic Carbon Nitrides for Green Light-Driven Photocatalysis.

Solar-driven organic transformations offer a sustainable strategy for the synthesis of high-value fine chemicals. However, most photoredox systems rely on high-energy light and costly molecular photosensitizers. Developing robust heterogeneous photocatalysts capable of efficient operation under low-energy visible light remains a critical challenge. Herein, we present a pyrimidine-mediated electronic modulation strategy to engineer ionic carbon nitrides for green-light-driven photocatalysis. Incorporation of 2,4,6-triaminopyrimidine during the thermal polymerization of potassium poly-(heptazine imide) induced controlled carbon doping within the framework, enabling band structure tuning, extended visible-light absorption, and enhanced charge separation and transport. The optimized material (0.5T-K) exhibited significantly improved photophysical properties, which translated into efficient catalytic performance under green-light irradiation. As a representative demonstration, the material enabled C-N cross-coupling with up to 99% conversion and sustained activity in extended reactions, while maintaining good recyclability. This work establishes a general strategy for tailoring the electronic structure of ionic carbon nitrides and highlights their potential as efficient, fully heterogeneous photocatalysts for low-energy, sustainable photoredox transformations.