INQUINOA, CONICET, Instituto de Química Física, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456, T4000CAN Tucumán, Argentina.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 May;75(5):1422-34. doi: 10.1016/j.saa.2010.01.012. Epub 2010 Feb 6.
Theoretical calculations on the molecular geometry and the vibrational spectrum of 4-hydroxybenzoic acid were carried out by the Density Functional Theory (DFT/B3LYP) method. In addition, IR and Raman spectra of the 4-hydroxybenzoic acid in solid phase were newly recorded using them in conjunction the experimental and theoretical data (including SQM calculations), a vibrational analysis of this molecular specie was accomplished and a reassignment of the normal modes corresponding to some spectral bands was proposed. The geometries of monomers and dimers in gas phase were optimized using the DFT B3LYP method with the 6-31G*, D95** and 6-311++G** basis sets. Also, both the vibrational spectra recorded and the results of the theoretical calculations show the presence of one stable conformer for the 4-hydroxybenzoic acid cyclic dimer. The B3LYP/6-31G* method was used to study the structure for cyclic dimer of 4-hydroxybenzoic acid and for a complete assignment our results were compared with results of the cyclic dimer of benzoic acid. A scaled quantum mechanical analysis was carried out to yield the best set of harmonic force constants. The formation of the hydrogen bond was investigated in terms of the charge density by the AIM program and by the NBO calculations.
采用密度泛函理论（DFT/B3LYP）方法对 4-羟基苯甲酸的分子几何形状和振动光谱进行了理论计算。此外，还结合实验和理论数据（包括 SQM 计算），使用它们对固态 4-羟基苯甲酸的红外和拉曼光谱进行了新的记录，对该分子的振动分析进行了完成，并对一些谱带的正则模式进行了重新分配。使用 DFT B3LYP 方法，在 6-31G*、D95** 和 6-311++G*基组上对气相中的单体和二聚体的几何形状进行了优化。此外，记录的振动光谱和理论计算结果都表明，4-羟基苯甲酸环状二聚体存在一个稳定的构象。使用 B3LYP/6-31G方法研究了 4-羟基苯甲酸环状二聚体的结构，并与苯甲酸环状二聚体的结果进行了比较，以进行完整的分配。对环状二聚体进行了量化力学分析，以产生最佳的谐波力常数集。使用 AIM 程序和 NBO 计算，从电荷密度的角度研究了氢键的形成。
Zotero 插件