title: Excited-state N-H···S hydrogen bond between indole and dimethyl sulfide: time-dependent density functional theory study.
abstract: The intermolecular hydrogen bond N-H···S between indole and dimethyl sulfide is theoretically investigated. The formation of N-H···S hydrogen bonds between indole and dimethyl sulfide in ground and excited states is confirmed by the analysis of geometric structure, Mulliken charge, and infrared spectra. The result shows that the S(1) state of hydrogen bonded indole-Me(2)S is mainly a charger transfer state, while the S(2) state is a local excited state and also the state corresponding to the experiment. More importantly, it is demonstrated that the intermolecular hydrogen bond N-H···S of indole-Me(2)S is strengthened in the S(1) and S(2) states compared to that in ground state. Moreover, the strengthening of intermolecular N-H···S hydrogen bond in excited state induces the fluorescence emission peak of indole shifts to the red. These findings may provide insights for further study of N-H···S hydrogen bonds existing in many biomolecular systems.
authors.affiliation: Department of Physics, Henan Normal University, Xinxiang 453007, China. yf-liu@henannu.edu.cn
authors.forename: Yufang
authors.initials: Y
authors.lastname: Liu
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Yang
authors.forename: Kai
authors.initials: K
authors.lastname: Jiang
authors.forename: Deheng
authors.initials: D
authors.lastname: Shi
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Sun
mesh_terms: D006860:Hydrogen Bonding; D007211:Indoles / Q000737:chemistry*; D011789:Quantum Theory; D013440:Sulfides / Q000737:chemistry*; D013997:Time Factors
chemical_list: D007211:Indoles; D013440:Sulfides; C030374:indole; C004784:dimethyl sulfide