Solvent effects on a derivative of 1, 3, 4-oxadiazole tautomerization reaction in water: A reaction density functional theory study. (23rd February 2020) - Tang, Weiqiang
Highlights: The solvent effects of oxadiazole tautomerization reactions are unraveled by using RxDFT. Theoretical predictions have overall good agreement with reported results. Assistance of water molecules in the reactions greatly reduces the free energy barriers. RxDFT has great potential in studying solvent effect on chemical reactions in solution. Abstract: In this work, we investigate the simple and water assisted tautomerization reaction in a derivative of 1, 3, 4-oxadiazole by means of the proposed multiscale reaction density functional theory (RxDFT). The complete scheme and reaction pathways among four different tautomers are investigated, and the free energy profiles of four corresponding tautomerization reactions in the absence and presence of 1–3 water molecules are calculated. The results show that the presence of liquid water considerably reduces the free energy barriers of the tautomerization reactions, but imposes negligible impact on the reaction free energies. The solvent effects are ascribed primarily to the assistance of water molecules, and then to the difference in solvation free energy. The satisfactory accuracy and low computational cost of RxDFT highlight its great potential for studying solvent effect on chemical reactions in solution compared with ab initio or QM/MM method.