Controlling Excited State Single versus Double Proton Transfer for 2,2′-Bipyridyl-3,3′-diol: Solvent Effect

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 121; no. 20; pp. 4002 - 4008
• Main Authors: Zhao, Jinfeng, Liu, Xiaoyan, Zheng, Yujun
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 25-05-2017
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/acs.jpca.7b01404

In this work, we theoretically investigate the sequential excited state double proton transfer (ESDPT) mechanism of a representative intramolecular hydroxyl (OH)-type hydrogen molecule 2,2′-bipyridyl-3,3′-diol (BP­(OH)2). We mainly adopt three kinds of different polar solvents (nonpolar cyclohexane (CYH), polar acetonitrile (ACN), and moderate chloroform (CHCl3)) to explore solvent effects on this system. Two intramolecular hydrogen bonds of BP­(OH)2 are testified to be strengthened in the S1 state, which provides possibility for ESDPT process. Explorations of charge redistribution and potential energy surfaces (PESs) reveal ESDPT process. Searching transition state (TS) structures in different polar aprotic solvents, we successfully regulate and control the stepwise ESDPT behaviors of BP­(OH)2 through solvent polarity.