溶剂调控的环己烯酮和吡啶酮激发态结构和衰变动力学

发布时间：2018-06-05 00:46

本文选题：2-吡啶酮 + 2-环己烯酮　；参考：《浙江理工大学》2017年硕士论文

【摘要】：2-吡啶酮类物质和2-环己烯酮类物质结构中含有羰基和碳碳双键结构,与核酸碱基中的胸腺嘧啶、尿嘧啶中所含结构相酮。通过研究这类化合物的激发态光物理和光化学行为,有助于认识和理解核酸碱基超快内转换机制(光稳定性),为生物体系中DNA光损伤机制提供短时结构动力学方面的支持。本文采用共振拉曼光谱实验结合量子波包理论和完全活化空间自洽场(Complete-Active-Space Self-Consistent-Field CASSCF)理论计算方法,研究2-吡啶酮、1-甲基-2-吡啶酮、3-甲基-2-吡啶酮、2-环己烯酮、2-甲基-2-环己烯酮、3-甲基-2-环己烯酮在环己烷、乙腈、水等溶剂中的激发态短时结构动力学和衰变通道,考察溶剂效应和甲基取代对激发态势能面的影响和衰变通道非绝热动力学中的调控作用,结果如下:(1)指认了研究体系在环己烷、乙腈和水等溶剂中的振动光谱、电子光谱和共振拉曼光谱。获取了六种物质的紫外光谱、荧光光谱、傅立叶红外光谱(FT-IR)、傅立叶拉曼光谱(FT-Raman)、显微拉曼光谱(Micro Raman)和共振拉曼光谱(resonance Raman)。采用密度泛函理论(Density Function Theory,DFT)计算了分子的电子基态结构和理论振动光谱,以此将实验振动光谱峰一一指认为对应理论计算的振动模。采用含时密度泛函理论(TD-DFT)计算电子吸收带的跃迁性质及跃迁振子强度,将紫外光谱吸收带归属为相应的电子跃迁。(2)获取了2-吡啶酮Sπ2态Franck-Condon区域短时结构动力学。采用含时波包理论单势能面模型对2-吡啶酮在乙腈溶剂中223.1和228.7 nm激发波长的共振拉曼光谱进行定量拟合,获得9个具有较大拉曼强度的振动模的无量纲简正模位移量。结合频率计算,将位移量转化为分子各内坐标随时间的变化量,从而获取Franck-Condon区域短时动力学中的结构信息。通过与CASSCF计算方法得到的2-吡啶酮Sπ2-min、Sπ2Sn2、Sπ2Sn1等激发态以及交叉点结构的比较,表明2-吡啶酮Sπ2态FC区域Sπ2态与Sn2态存在强烈振动耦合;在远离FC区域时,波包主要前往Sπ2Sn1交叉点;部分波包前往Sπ2-min,并伴随有较小量子产率的荧光。2-吡啶酮在Sn1态势能面上可发生质子转移。1-氘代-2-吡啶酮,1-甲基-2-吡啶酮的共振拉曼光谱和CASSCF计算表明2-吡啶酮Sπ2态势能面上不会发生质子转移。1-氘代-2-吡啶酮共振拉曼光谱的峰频率与强度模式与1-甲基-2-吡啶酮相似,而与2-吡啶酮差异明显。与N原子相连的H与溶剂的相互作用使2-吡啶酮包含C=O,C=C伸缩振动和N—H面内弯曲振动的简振模发生重组,改变激发态势能面,从而影响激发态衰变动力学。(3)探讨了溶剂及甲基取代对2-环己烯酮激发态势能面和衰变通道的调控机制。2-环己烯酮、2-甲基-2-环己烯酮、3-甲基-2-环己烯酮在乙腈、甲醇和水中共振拉曼光谱的强度模式表明,三者激发态FC区域的短时结构动力学主要是沿着C1=O7和C2=C3伸缩振动展开的。三者在不同溶剂中展现出不同强度的双荧光现象,通过CASSCF的激发态结构计算,将两个荧光带分别指认为两个不同构型S_2(P1)和S_2(P2)的S_2-min→S0’的跃迁。CASSCF计算同时获得了三个S_2S_1交叉点,揭示了2-环己烯酮S_2态衰变通道的多维性。溶剂和甲基取代共同调控着S_2态不同衰变通道的效率。
[Abstract]:The structure of 2- pyridones and 2- cyclohexenones contains the structure of carbonyl and carbon carbon double bonds, with thymine and uracil in nucleic acid bases. By studying the photophysical and photochemical behavior of the excited state of these compounds, it is helpful to understand and understand the ultra fast internal conversion mechanism (light stability) of the nucleate base. The DNA optical damage mechanism in the body provides short time structural dynamics support. In this paper, the resonance Raman spectroscopy is used to study the 2- pyridone, 1- methyl -2- pyridone, 3- methyl -2- pyridone, 2- ring, and the quantum wave packet theory and the fully activated space self consistent field (Complete-Active-Space Self-Consistent-Field CASSCF) theory. The short-time structural dynamics and decay channels of 2- methyl -2- cyclohexenone and 3- methyl -2- cyclohexenone in cyclohexane, acetonitrile, water and other solvents, the effect of solvent effect and methyl substituent on the energy surface of the excitation situation and the regulation of the adiabatic kinetics of the decay channel are investigated. The results are as follows: (1) the study system is identified in the ring The vibrational spectra, electron spectra and resonance Raman spectra of hexane, acetonitrile and water were obtained. The UV spectra, fluorescence spectra, Fu Liye infrared spectroscopy (FT-IR), Fu Liye Raman spectroscopy (FT-Raman), Micro Raman and resonance Raman (resonance Raman) were obtained. The density functional theory (Density Func) was used. Tion Theory, DFT) calculated the structure of the electronic ground state and the theoretical vibration spectrum of the molecule. In this way, the experimental vibrational spectral peak was referred to as the corresponding theoretical vibration mode. The transition property of the electron absorption band and the intensity of the transition oscillator were calculated by the time density functional theory (TD-DFT), and the UV absorption band was attributed to the corresponding electron jump. (2) the short time structure dynamics of 2- pyridone S PI 2 state Franck-Condon region was obtained. The resonant Raman spectra of 2- pyridone in acetonitrile solvent at the excitation wavelength of 223.1 and 228.7 nm in the acetonitrile solvent were fitted by the time wave packet theory single potential surface model, and 9 dimensionless normal mode displacement of the vibration modes with large Raman intensity were obtained. In the calculation of frequency, the displacement is converted into the variation of the molecule's internal coordinates with time, and the structure information in the short time dynamics of the Franck-Condon region is obtained. The comparison of the excited states of the 2- pyridone S PI 2-min, S PI 2Sn2, S PI 2Sn1 and the structure of the crossing point obtained by the CASSCF method shows that the S PI 2 state FC region of 2- pyridone is in and out of the region. There is a strong vibration coupling in the N2 state; when far away from the FC region, the wave packet mainly goes to the S PI 2Sn1 intersection; some wave packets go to S PI 2-min, and the fluorescent.2- pyridone with a small quantum yield can occur on the Sn1 state potential energy surface with proton transfer.1- deuteron -2- pyridone, the resonance Raman spectrum of 1- methyl -2- pyridone and the calculation of pyridine The peak frequency and intensity mode of the resonance Raman spectrum of the proton transfer.1- deuterated -2- pyridone is similar to that of the 1- methyl -2- pyridone, but the difference is distinct from the 2- pyridone. The interaction between H and the solvent linked to the N atom makes 2- pyridone containing C=O, C=C telescopic vibration and a simple vibration mode of the bending vibration in the N and S surface. Recombination, changing the energy surface of the excited state, and thus affecting the dynamics of the excited state decay. (3) the regulation mechanism of solvent and methyl substituent on the energy surface and decay channel of 2- cyclohexenone excitation.2- cyclohexene, 2- methyl -2- cyclohexenone, 3- methyl -2- cyclohexenone in acetonitrile, methanol and water resonance Raman spectra indicate, three The short time structure dynamics of the excited state FC region is mainly expanded along the C1=O7 and C2=C3 expansion vibration. The three ones exhibit different intensity double fluorescence phenomena in different solvents, and the two fluorescent bands refer to the transition.CASSCF of the S_2-min to S0 'of the two different configurations of S_2 (P1) and S_2 (P2), respectively. Three S_2S_1 intersection points were obtained at the same time, and the multidimensional properties of the S_2 state decay channel of 2- cyclohexenone were revealed. The efficiency of different decay channels in the S_2 state was controlled by the solvent and methyl substitution.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O644.1

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