title: Solvent-dependent dynamics of hydrogen bonding structure 5-(methylthio)-1, 3, 4-thiadiazole-2(3H)-thione as determined by Raman spectroscopy and theoretical calculation.
abstract: The vibration spectra of 5-(methylthio)-1,3,4-thiadiazole-2(3H)-thione (MTTN) in acetonitrile (CH3CN), methanol (CH3OH) and water (H2O) solvents were collected and evaluated via deuterium isotopic substitution Raman spectroscopic experiments. These experiments were combined with the quantum chemical theoretical calculations using the PCM solvent model and normal mode analysis. The results confirmed that the MTTN in CH3CN, CH3OH and H2O have hydrogen bonding (H-bonding) MTTN(solvent)nclusters that produce significantly different Raman intensity patterns in different solvents. Combined with the normal Raman assignment, most resonance Raman spectra were assigned to the vibration modes of the H-bonding MTTN(CH3CN), MTTN(CH3OH)3and MTTN(H2O)3clusters in CH3CN, CH3OH and H2O. The theoretically-predicted frequencies and intensities in different surrounding environments enabled reliable assignments of Raman bands. The intermolecular>NH⋯O and >NH⋯N H-bonding interactions are key constituents of stable thione structures in MTTN. This underlines the significant structural differences of MTTN in CH3CN, CH3OH and H2O. H-bonding perturbation of MTTN reveal important insights about the intermolecular excited state proton transfer (ESPT) reaction mechanisms in the Franck-Condon region structural dynamics of the thione→thiol tautomer in CH3OH and H2O.
authors: Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
authors: Sumei
authors: S
authors: Pang
authors: Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China; State Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education(MOE), Zhejiang Sci-Tech University, Hangzhou 310018, China. Electronic address: yyzhao@zstu.edu.cn.
authors: Yanying
authors: Y
authors: Zhao
authors: Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
authors: Liu
authors: L
authors: Xin
authors: Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China; State Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education(MOE), Zhejiang Sci-Tech University, Hangzhou 310018, China.
authors: Jiadan
authors: J
authors: Xue
authors: Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China; State Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education(MOE), Zhejiang Sci-Tech University, Hangzhou 310018, China.
authors: Xuming
authors: X
authors: Zheng
keywords: 5-(Methylthio)-1,3,4-thiadiazole-2(3H)-thione; Intermolecular hydrogen bonding; Raman spectroscopy; Structural dynamics; Theoretical calculation