Deuteration of arenes in D2O exclusively driven by single-atom Pt sites under visible light

Deuterated arenes play crucial roles in medicinal chemistry and materials science (e.g., psychotropic drugs and deuterated OLEDs). However, the desired late-stage deuteration via conventional hydrogen isotope exchange methods always demands expensive isotopic reagents (e.g., D2, C6D6, or C2H5OD), metal complex catalysts, or harsh conditions ( ≥ 120 oC, 20 bar H2). Here, we report a single-atom photocatalytic strategy for efficient deuteration of electron-rich arenes using D2O as the deuterium source. Under visible light irradiation at ambient temperature in an inert atmosphere, a single-atom photocatalyst (Pt1/TiO2) affords high deuterium incorporation across 54 electron-rich arene substrates. The protocol is mild, sustainable, and scalable: gram-scale synthesis of deuterated arenes (11.98 g, 100 mmol) was successfully realized. Mechanistic studies indicate that the catalytically active sites are primarily Pt–O coordinate bonds, whose light-modulated charge distribution facilitates a possible electrophilic platinization pathway for C–H activation before H/D exchange. Deuterated arenes are valuable in medicinal chemistry and materials science, but conventional hydrogen isotope exchange often requires costly reagents, metal complex catalysts or harsh conditions. Here, the authors report a single-atom photocatalytic strategy using D₂O as the sole deuterium source to efficiently deuterate electron-rich arenes under mild, scalable conditions.