CAJ | 학술논문

采用共振拉曼光谱学结合量子化学计算研究了2-硫代嘧啶酮(2TPM)和2-硫代吡啶酮(2TP)在B-带吸收时的动态结构.在气相时,2-巯基嘧啶(2MPM,硫醇式)比2TPM(硫代酮式)更稳定,能量差约为15.1 kJ·mol-1,而在水和乙腈溶液中,2TPM比2MPM更稳定,能量差分别为29.3和28.0 kJ·mol-1.气相及基电子态时,由B3LYP/6-311++G(d,p)计算水平获得的2TPM和2MPM之间发生质子转移异构化反应的过渡态能垒约为130 kJ· mol-1.2TPM三个吸收带分别被指认为πH→π*L,πH→π*L+1和πH-1→π*L跃迁.基于对2TPM在固体和溶液相傅里叶变换-拉曼(FT-Raman)和傅里叶变换-红外(FT-IR)光谱测量,以及B3LYP/6-311++G(d,p)计算,开展了2TPM在水和乙腈溶液中的B-带共振拉曼光谱的振动指认,由此获得了2TPM的动态结构,并与2TP的动态结构进行了比较.2TPM和2TP动态结构的差异反映了ππ*/πσ*锥形交叉点结构的差异,因此,可被用于洞察光诱导的氢原子脱离-复合机制.
채용공진랍만광보학결합양자화학계산연구료2-류대밀정동(2TPM)화2-류대필정동(2TP)재B-대흡수시적동태결구.재기상시,2-구기밀정(2MPM,류순식)비2TPM(류대동식)경은정,능량차약위15.1 kJ·mol-1,이재수화을정용액중,2TPM비2MPM경은정,능량차분별위29.3화28.0 kJ·mol-1.기상급기전자태시,유B3LYP/6-311++G(d,p)계산수평획득적2TPM화2MPM지간발생질자전이이구화반응적과도태능루약위130 kJ· mol-1.2TPM삼개흡수대분별피지인위πH→π*L,πH→π*L+1화πH-1→π*L약천.기우대2TPM재고체화용액상부리협변환-랍만(FT-Raman)화부리협변환-홍외(FT-IR)광보측량,이급B3LYP/6-311++G(d,p)계산,개전료2TPM재수화을정용액중적B-대공진랍만광보적진동지인,유차획득료2TPM적동태결구,병여2TP적동태결구진행료비교.2TPM화2TP동태결구적차이반영료ππ*/πσ*추형교차점결구적차이,인차,가피용우동찰광유도적경원자탈리-복합궤제.
The dynamic structures of 2-thiopyrimidone (2TPM) and 2-thiopyridone (2TP) in B-band absorptions were studied using the resonance Raman spectroscopy combined with quantum chemical calculations.In gas phase,2-thiopyrimidine (2MPM,the thiol form) was more stable than 2TPM (the thione form) by ～15.1 kJ· mol-1,whereas in water and acetonitrile 2TPM was more stable than 2MPM by 29.3 and　28.0 kJ · mol-1,respectively.The transition barrier for the ground state proton transfer tautomerization reaction between 2TPM and 2MPM was ～130 kJ· mol-1 in gas phase on the basis of the B3LYP/6-311 ++G(d,p) level of theory calculations.The three absorption bands of 2-thiopyrimidone were respectively　assigned as πH →π*L,πH →π*L+1,and πH-1→π*L transitions.The vibrational assignments were carried out for the B-band resonance Raman spectra of 2TPM in water and acetonitrile solvents on the basis of the measurements from the Fourier transform (FT)-Raman and Fourier transform-infrared (FT-IR) spectra of 2TPM in solid and/or in solution phases and B3LYP/6-311++G(d,p) computations.The dynamic structures of 2TPM and 2TP were obtained by analysis of the resonance Raman intensity pattern.The differences in the dynamic structures of 2TPM and 2TP reflected differences in the structures of their ππ*/πσ* conical intersection points,and therefore could be used to provide insight into the photoinduced hydrogen-atom detachment-attachment mechanism.