Donor-acceptor engineering of a triplet-exciton-optimized MOF photocatalyst for efficient singlet oxygen-mediated oxidation
Kai Wang, Chang‐Tai Li, Guolei Zhang, Han Wang, Lin Geng, Bo Zhang, Mei‐Hui Yu, Jijie Zhang, Ze Chang, Xian‐He Bu
Abstract
ABSTRACT The exploration of photocatalysts (PCs) for efficient singlet oxygen (1O2)-based photocatalytic oxidation is critical and challenging. Herein, a new series of donor-acceptor metal-organic frameworks (D-A MOFs) are constructed through the engineering of the D-A system, and investigated as PCs for the 1O2 oxidation reaction. By regulating the intersystem crossing and reversed intersystem crossing features of the D-A system, D-A MOFs could reveal highly tunable triplet-exciton generation. Via the synergy of the enhanced electron transfer properties and the effective energy transfer to ground-state O2, the optimized D-A MOF (C1) could reveal remarkable activity toward 1O2 generation under appropriate irradiation, which is fully proven by the highly efficient oxidation and detoxification of mustard simulant 2-chloroethyl ethyl sulfide into 2-chloroethyl ethyl sulfoxide (conversion and selectivity >99% within 15 min). Moreover, the application of C1 for the photocatalytic oxidation of dihydroartemisinic acid to artemisinin results in the highest selectivity and yield (selectivity 88% and conversion >99% at 25°C) among all reported homo- or heterogeneous PCs.