Ultrasmall CsPbBr Nanocrystals as a Recyclable Heterogeneous Photocatalyst in 100% - and Anti-Markovnikov Sulfinylsulfonation of Terminal Alkynes.

The precise synthesis of ultrasmall, monodisperse CsPbBr nanocrystals is crucial due to their enhanced photophysical properties resulting from strong quantum confinement effects. Traditional methods struggle with size control, complicating synthesis. Although CsPbBr nanocrystals find applications in LEDs and photovoltaics, their use in photocatalysis for organic reactions remains limited. Our study introduces ultrasmall TBIA-CsPbBr nanocrystals (∼5.6 nm), synthesized a three-precursor hot injection method using tribromoisocyanuric acid (TBIA) as a bromine precursor for the first time. These nanocrystals exhibit a near-unity photoluminescence quantum yield (PLQY) of 0.99 and an elevated oxidation potential of +1.80 V. We demonstrate their efficacy as recyclable heterogeneous photocatalysts in a one-pot, 100% -selective, anti-Markovnikov sulfinylsulfonation of terminal alkynes under visible light, achieving a high product conversion rate (PCR) of 62,500 μmol g h and recyclability for up to five cycles. Density functional theory (DFT) calculations support the exclusive formation of the -isomer. TBIA-CsPbBr outperforms other CsPbBr perovskites in photocatalysis, with superior efficiency attributed to their extended excited-state lifetime and higher surface area, which accelerates the organic transformation process.