title: A QM/MM MD insight into photodynamics of hypoxanthine: distinct nonadiabatic decay behaviors between keto-N7H and keto-N9H tautomers in aqueous solution.
abstract: Extensive ab initio surface-hopping dynamics simulations have been used to explore the excited-state nonadiabatic decay of two biologically relevant hypoxanthine keto-N7H and keto-N9H tautomers in aqueous solution. QM/MM calculations and QM/MM-based MD simulations predict different hydrogen bonding networks around these nucleobase analogues, which influence their photodynamical properties remarkably. Furthermore, different solvent effects on the conical intersection formation of keto-N7H and keto-N9H were found in excited-state MD simulations, which also change the lifetimes of the excited states. In comparison with the gas-phase situation, the S1 → S0 nonradiative decay of keto-N7H is slightly faster, while this decay process of keto-N9H becomes much slower in water. The presence of π-electron hydrogen bonds in the solvated keto-N7H is considered to facilitate the S1 → S0 nonradiative decay process.
authors.affiliation: State Key Laboratory for Physical Chemistry of Solid Surfaces and Fujian Provincial Key Lab of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China. zxcao@xmu.edu.cn.
authors.forename: Xugeng
authors.initials: X
authors.lastname: Guo
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zexing
authors.initials: Z
authors.lastname: Cao
mesh_terms: D005740:Gases / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D019271:Hypoxanthine / Q000737:chemistry*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D055668:Photochemical Processes; D011789:Quantum Theory; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D005740:Gases; D014867:Water; D019271:Hypoxanthine; D006859:Hydrogen