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使用密度泛函理论B3LYP方法,对西红花酸二甲酯的结构、电子吸收光谱、热力学性质进行理论计算研究,并基于Tomasi的极化统一场模型(PCM)讨论溶剂效应.结果显示,溶剂对西红花酸二甲酯的前线分子轨道特征几乎无影响,溶剂作用使该分子的最大吸收波长红移约42 nm,红移程度与溶剂极性无关.西红花酸二甲酯分子的气态热力学性质与温度的关系式分别为:Cm p=189.782+0.925T,S m=457.503+1.366T,H m=1164.899+0.195T+4.671×10-4T2,Gm=1164.899-0.263T-8.989×10-4T2.298 K时,西红花酸二甲酯分子的气态标准摩尔生成焓和标准摩尔生成自由能分别为-1180.67和-733.23 kJ·mol-1.
The structure, electron absorption spectra and thermodynamic properties of crocetin were studied theoretically using density functional theory (B3LYP) method and the solvent effect was discussed based on Tomasi’s Polarization Uniform Field Model (PCM). The results showed that the solvent Has no effect on the front molecular orbital characteristics of crocetin and the solvent red shifts the maximum absorption wavelength of the molecule about 42 nm and the degree of red-shift is independent of the polarity of the solvent. Dimethyl crocetin The relationship between the gaseous thermodynamic properties and the temperature is respectively: Cm p = 189.782 + 0.925T, S m = 457.503 + 1.366T, H m = 1164.899 + 0.195T + 4.671 × 10-4T2, Gm = 1164.899-0.263T-8.989 × At 10-4T2.298 K, the molar standard enthalpy of formation and the standard molar formation free energy of the crocetin molecules were -1180.67 and -733.23 kJ · mol-1, respectively.