Visible Light Photoredox Catalysis Using Water-Soluble Quantum Dots: Aerobic Hidroxylation of Arylboronic Acids

CASTRO GODOY, WILBER D.; SCHMIDT, LUCIANA C; FLORES-OÑAS DIEGO R.; JULIA PÉREZ PRIETO; ALICIA B. PEÑÉÑORY; RAQUEL E. GALIAN; JUAN E. ARGÜELLO

Córdoba

Congreso; Nanocordoba 2014; 2014

Quantum Dots (QDs) are semiconductor nanoparticles with unique size-dependent optical and electronic properties. The QDs have interest in the photocatalytic production of superoxide anion by electron transfer from the conduction band to molecular oxygen under visible light irradiation. Herein, we report the preparation of water-dispersible CdS QDs capped with mercaptopropionic and mercaptosuccinic acids as ligands. The QDs were synthesized following a previously described methodology with some modifications.[1],[2] The use of these organic ligands prevents the QD aggregation, provides their aqueous dispersibility and allow their support on TiO2 nanoparticles (CdS/TiO2). Moreover, the photocatalytic performance of CdS and CdS/TiO2 were tested in the aerobic oxidative hydroxylation of arylboronic acids under visible lamps irradiation. In this reaction, the superoxide radical anion generated from the exciton of the QDs react with arylboronic acids because of its Lewis acidity, followed by a series of rearrangements to provide aryl alcohols. [3] This represents the first example of the use of QDs nanoparticle driven chemical transformation under environmental friendly conditions. References [1] Kaur, G.; Tripathi, S. Mater. Chem. Phys. 2014, 2, 514-523. [2] Kumar, P.; Kukkar, D.; Deep, A.; Sharma, S.; Bharadwaj, L. Adv. Mat. Lett. 2012, 3 (6), 471-475. [3] Zou, Y-Q.; Chen, J-R.; Lui, X-P.; Lu, L-Q.; Davis, R. L.; Jorgensen, K. A.; Xiao, W-J. Angew. Chem. Int. Ed. 2012, 51, 787-788.