Modulating the Surface and Photophysical Properties of Carbon Dots to Access Colloidal Photocatalysts for Cross-Couplings

Photoredox-mediated Ni-catalyzed cross-couplings are effective for forming carbon-heteroatom bonds using noble metal complexes as photocatalysts. We developed colloidal carbon dot (CD) nano-photocatalysts by tuning their surface and photoluminescence properties. These CDs, especially those decorated with amino groups, facilitated Ni-mediated cross-couplings between aryl halides and thiols under mild, base-free conditions. Mechanistic studies revealed that Ni co-catalysts quench CD excited states dynamically, and pyridinium iodide (pyHI) acts as a photocatalyst in these transformations.