Synthesis of Visible-Light-Responsive Nanocarbon and Application for Photocatalytic Carbon–Carbon Bond Formation

Visible-light-responsive nanocarbon was systematically synthesized via a one-step hydrothermal method, using citric acid and Congo Red; this nanocarbon exhibited visible-light absorption at 516 nm and photocatalytic activity for the carbon–carbon bond-forming reaction between benzylamine and ethyl cyanoacetate. Mechanistic investigations proved that this system generates radicals and the reactions proceed via radical pathways, which are confirmed by electron spin resonance. A metal-free, mildly conditioned, and recyclable photocatalytic reaction was achieved by the visible-light-responsive nanocarbon system.