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Enhancing the Rate of Quantum Dot-Photocatalyzed Carbon-Carbon Coupling by Tuning the Composition of the Dot's Ligand Shell.

ABSTRACT

This paper describes the photo-redox catalysis of a C-C coupling reaction between 1-phenyl pyrrolidine (PhPyr) and phenyl trans-styryl sulfone (PhSO2) by visible light-absorbing colloidal CdS quantum dots (QDs), without a sacrificial oxidant or reductant, and without a co-catalyst. Simple kinetic analysis reveals that photo-oxidation of PhPyr by the QD is the rate-limiting step. Disordering of the ligand shell of the QDs by creating mixed monolayers of oleate and octylphosphonate increases the initial rate of the reaction by a factor of 2.3 and the energy efficiency (mol product / joule of incident photons) of the reaction by a factor of 1.6 by facilitating the hole transfer step.