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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8.9×103cm-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.
Methyl 3-nitrosalicylate and methyl 5-nitrosalicylate were synthesized by the nitration reaction of ferric nitrate and methyl salicylate, and their structures were characterized by IR, 1HNMR, UV-Vis absorption spectra And the fluorescence spectra were used to characterize the products.The quantum chemistry calculation results were used to explain the differences of their properties in IR, NMR, UV-Vis absorption spectra and fluorescence spectra.B3LYP / 6-31G ** and natural valence bond orbital The calculation results show that due to the stronger intramolecular hydrogen bonding of methyl 3-nitrosalicylate, the infrared absorption of hydroxyl and carbonyl groups is more red than that of methyl 5-nitrosalicylate. The hydrogen of phenolic hydroxyl group The spectrum shift to high displacement, and the ultraviolet absorption has an enhancement effect.According to the method of CIS / 6-31G **, the intramolecular protons of methyl salicylate and methyl 3-nitrosalicylate are calculated in the ground state and excited state And the Stokes displacements obtained from the potential energy curves are 8.4 × 103 and 8.9 × 103 cm-1, respectively. All of the results show that due to the different intramolecular hydrogen bonds, methyl salicylate, 3-nitro The spectral properties of methyl salicylate and methyl 5-nitrosalicylate are not the same.