物理化学学报 >> 2009, Vol. 25 >> Issue (10): 2118-2122.doi: 10.3866/PKU.WHXB20091005

研究论文 上一篇    下一篇

水杨酸甲酯及其与硝酸铁硝化产物光谱性质的比较

刘艳珠, 张玲, 李霞, 李永绣   

  1. 南昌大学理学院化学系, 南昌 330031
  • 收稿日期:2009-05-06 修回日期:2009-06-26 发布日期:2009-09-29
  • 通讯作者: 李永绣 E-mail:yxli@ncu.edu.cn

Comparison among the Spectral Properties ofMethyl Salicylate and Its Nitration Products by Iron (III) Nitrate

LIU Yan-Zhu, ZHANG Ling, LI Xia, LI Yong-Xiu   

  1. Department of Chemistry, School of Science, Nanchang University, Nanchang 330031, P. R. China
  • Received:2009-05-06 Revised:2009-06-26 Published:2009-09-29
  • Contact: LI Yong-Xiu E-mail:yxli@ncu.edu.cn

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摘要：

通过硝酸铁和水杨酸甲酯的硝基化反应, 合成了3-硝基水杨酸甲酯和5-硝基水杨酸甲酯. 并用红外光谱、核磁共振光谱、紫外-可见吸收光谱和荧光光谱对产物进行了表征. 用量子化学计算结果对其红外光谱、核磁共振光谱、紫外-可见吸收光谱和荧光光谱的性质差异进行了解释. B3LYP/6-31G**和自然价键轨道方法计算结果表明, 由于3-硝基水杨酸甲酯具有更强的分子内氢键, 其羟基和羰基的红外吸收比5-硝基水杨酸甲酯的红移了, 酚羟基的氢谱移向了高位移, 紫外吸收产生了增色效应. 基于CIS/6-31G**方法, 计算了水杨酸甲酯和3-硝基水杨酸甲酯基态和激发态下的分子内质子转移的势能曲线, 由势能曲线进一步得到它们的Stokes位移分别为8.4×103和8.9×103 cm-1. 所有结果表明, 由于分子内氢键强弱不同, 导致水杨酸甲酯、3-硝基水杨酸甲酯和5-硝基水杨酸甲酯的光谱性质不一样.

关键词: 分子内氢键, 硝化, 水杨酸甲酯, B3LYP/6-31G**

Abstract:

Methyl 3-nitrosalicylate (3-MNS) and methyl 5-nitrosalicylate (5-MNS) were synthesized by a nitration reaction between methyl salicylate (MS) and iron (III) nitrate under reflux. 3-MNS and 5-MNS were characterized by infrared spectra (IR), proton nuclear magnetic resonance spectra (1H-NMR), electronic absorption spectra (UV-Vis), and photoluminescence (PL). The structures of 3-MNS and 5-MNS were fully optimized at the B3LYP/6-31G** level. The optimized results and nature bond orbital (NBO) analysis results were used to illustrate the red-shift of the O—H and C=O stretching vibrations in the IR, the lower field shift of the phenol hydroxyl proton chemical shift in 1H-NMR, and the bathochromic shift in the UV-Vis spectra of 3-MNS. Potential energy surfaces for the intramolecular proton transfer of ground (GSIPT) and excited (ESIPT) states of MS and 3-MNS were obtained and the Stokes-shift values for MS and 3-MNS were computed to be 8.4 ×103 and 8.9×103 cm -1 using CIS/6-31G**, respectively. All these results demonstrate that differences in intramolecular hydrogen bonding in MS, 3-MNS, and 5-MNS give rise to large differences in their spectral properties.

Key words: Intramolecular hydrogen bond, Nitration, Methyl salicylate, B3LYP/6-31G**