A QM/MM MD insight into photodynamics of hypoxanthine: distinct nonadiabatic decay behaviors between keto-N7H and keto-N9H tautomers in aqueous solution

作者：Guo, Xugeng; Zhao, Yuan; Cao, Zexing^*

来源：Physical Chemistry Chemical Physics, 2014, 16(29): 15381-15388.

DOI：10.1039/c4cp01928h

• EXCITED-STATE DYNAMICS
• AB-INITIO
• MOLECULAR-DYNAMICS
• QUANTUM
• SYSTEM
• WATER
• IMPLEMENTATION
• DEACTIVATION
• SIMULATION
• SPECTRA

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 S-1 -> S-0 nonradiative decay of keto-N7H is slightly faster, while this decay process of keto-N9H becomes much slower in water. The presence of pi-electron hydrogen bonds in the solvated keto-N7H is considered to facilitate the S-1 -> S-0 nonradiative decay process.

• 出版日期2014
• 单位厦门大学