Photoelectrocatalytic C-C and C-N bond formation using a lead-free metal halide double perovskite photoanode Wei Xin Chan 1 , Adisak Thanetchaiyakup 1 , Mansour Sadek 1 , Yonghao Xiao 2 and Han Sen Soo 1 1 School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 21 Nanyang Link, Singapore 637371, Singapore, 2 School of Marine Science and Engineering, Hainan University, Haikou, 570228, China Photoelectrocatalysis offers a powerful and efficient method for driving organic transformations by combining light and electrical energy to generate reactive intermediates under mild conditions. In this poster, I will present the application of a metal halide perovskite-based photoanode device for C(sp³)-H activation leading to C-C or C-N bond formation. 1 A mechanochemically-synthesized 2,3 lead-free, alloyed double perovskite (Cs 2 Ag 0.95 Na 0.05 BiBr 6 ) was used as the photoelectrocatalyst to facilitate cross-coupling reactions under visible light irradiation and at ambient conditions, in the presence of 9,10-diphenylanthracene as a co-catalyst. We conducted extensive characterization by electrochemical analyses, powder X-ray diffraction, ultraviolet photoelectron spectroscopy, and scanning electron microscopy to verify the high photoelectrocatalytic activity and structural integrity of the Cs 2 Ag 0.95 Na 0.05 BiBr 6 -based photoanode. Under optimal conditions, aliphatic substrates underwent C-H activation and coupling with electron-deficient SOMOphiles to afford C-C coupled products with up to 94% yields and C-N coupled products with up to 99% yields. In addition, we performed mechanistic studies including isotope-labelling experiments, radical-scavenging experiments, and density functional theory calculations to reveal that the reaction proceeded via photogenerated ●Br radicals that induce hydrogen atom transfer of the solvent to form nucleophilic alkyl radicals. These alkyl radicals then underwent polarity-matched addition to electron-deficient alkenes or azo compounds to form the desired C-C or C-N products. We surmise that our study creates a new frontier in the application of metal halide perovskites as photoelectrocatalysts for the chemical diversification of organic small molecules.
References 1. A. Thanetchaiyakup, M. Sadek, W. X. Chan, Y. Qian, J. Yang, G. Bati, Y. Xiao and H. S. Soo, JACS Au , 2025, https://doi. org/10.1021/jacsau.5c00366 2. Y. Xiao, K. Choudhuri, A. Thanetchaiyakup, W. X. Chan, X. Hu, M. Sadek, Y. H. Tam, R. G. Loh, S. N. B. Shaik Mohammed, K. J. Y. Lim, J. Z. Tan, F. Garcia, V. Chellappan, T. S. Choksi, Y. Lim, H. S. Soo, Adv. Sci. 2024, 11 , 2309714.3. 3. Z. Hong, D. Tan, R. A. John, Y. K. E. Tay, Y. K. T. Ho, X. Zhao, T.C. Sum, N. Mathews, F. Garcia, H.S. Soo, iScience , 2019, 16 , 312-325.
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