CsPbBr<sub>3</sub> Perovskite Polyhedral Nanocrystal Photocatalysts for Decarboxylative Alkylation via C<sub>sp<sup>3</sup></sub>–H Bond Activation of Unactivated Ethers
Soumya Mondal, Souvik Banerjee, Suman Bera, Subal Mondal, Siba P. Midya, Rajkumar Jana, Rakesh K. Behera, Ayan Datta, Narayan Pradhan, Pradyut Ghosh
Abstract
Halide perovskite nanocrystals have recently emerged as high-performance light-harvesting materials. They are also extensively studied for the fabrication of both light-emitting and photovoltaic devices. In comparison, their implementation as photocatalysts to trigger different organic reactions is limited. To add more diversity in catalysis, herein, different shapes and heterostructures of CsPbBr 3 perovskite polyhedral nanocrystals are explored for visible-light-mediated room temperature photocatalytic C sp 3 –H bond-activated alkylation of cyclic ether using feedstock α,β-unsaturated acids as the keto-alkyl source. It started with the decarboxylative coupling of cinnamic acid at the α-position of tetrahydrofuran (THF) and extended to several derivatives. The facets of nanocrystals matter, and hence, differently shaped nanocrystals showed variable rates of catalytic activities. With density functional theory calculation, the surface-adsorption-induced charge carrier transfer mechanism to facilitate such reactions is established. Different semiconductors and noble metal heterostructures that quenched the emission are also compared, and their inactiveness in catalysis was also correlated to the proposed mechanism. Combining all these observations, the roles of light, catalytic surfaces, oxygen, the nature of hosts, and coupling with other material heterostructures are analyzed in detail and reported. Such reactions with C sp 3 –H bond activation can lead to complex chemical scaffolds, unveiling an underexplored domain of heterogeneous photocatalytic organic reactions for C sp 3 –C sp 3 cross-coupling.