Anni Diane, Amika Mbema Jean Claude, Malloum Alhadji, Conradie Jeanet
Department of Physics, Faculty of Science, University of Maroua, PO BOX 46, Maroua, Cameroon.
Department of Chemistry, University of the Free State, PO BOX 339, Bloemfontein, 9300, South Africa.
J Mol Model. 2024 Jan 12;30(2):38. doi: 10.1007/s00894-023-05810-2.
Micro-hydration of the aminobenzoic acid is essential to understand its interaction with surrounding water molecules. Understanding the micro-hydration of the aminobenzoic acid is also essential to study its remediation from wastewater. Therefore, we explored the potential energy surfaces (PESs) of the para-aminobenzoic acid-water clusters, ABW[Formula: see text], [Formula: see text], to study the microsolvation of the aminobenzoic acid in water. In addition, we performed a quantum theory of atoms in molecules (QTAIM) analysis to identify the nature of non-covalent bondings in the aminobenzoic acid-water clusters. Furthermore, temperature effects on the stability of the located isomers have been examined. The located structures have been used to calculate the hydration free energy and the hydration enthalpy of the aminobenzoic acid using the cluster continuum solvation model. The hydration free energy and the hydration enthalpy of the aminobenzoic acid at room temperature are evaluated to be -7.0 kcal/mol and -18.1 kcal/mol, respectively. The hydration enthalpy is in perfect agreement with a previous experimental estimate. Besides, temperature effects on the calculated hydration enthalpy and free energy are reported. Finally, we calculated the gas phase binding energies of the most stable structures of the ABW[Formula: see text] clusters using twelve functionals of density functional theory (DFT), including empirical dispersion. The DFT functionals are benchmarked against the DLPNO-CCSD(T)/CBS. We have found that the three most suitable DFT functionals are classified in the following order: PW6B95D3 > MN15 > [Formula: see text]B97XD. Therefore, the PW6B95D3 functional is recommended for further study of the aminobenzoic acid-water clusters and similar systems.
The exploration started with classical molecular dynamics simulations followed by complete optimization at the PW6B95D3/def2-TZVP level of theory. Optimizations are performed using Gaussian 16 suite of codes. QTAIM analysis is performed using the AIMAll program.
对氨基苯甲酸的微水合作用对于理解其与周围水分子的相互作用至关重要。理解对氨基苯甲酸的微水合作用对于研究其从废水中的修复也至关重要。因此，我们探索了对氨基苯甲酸 - 水簇ABW[化学式：见正文]、[化学式：见正文]的势能面（PESs），以研究对氨基苯甲酸在水中的微溶剂化作用。此外，我们进行了分子中的原子量子理论（QTAIM）分析，以确定对氨基苯甲酸 - 水簇中非共价键的性质。此外，还研究了温度对所定位异构体稳定性的影响。所定位的结构已用于使用簇连续介质溶剂化模型计算对氨基苯甲酸的水合自由能和水合焓。室温下对氨基苯甲酸的水合自由能和水合焓分别评估为 -7.0 kcal/mol和 -18.1 kcal/mol。水合焓与先前的实验估计完全一致。此外，还报告了温度对计算得到的水合焓和自由能的影响。最后，我们使用包括经验色散在内的十二种密度泛函理论（DFT）泛函计算了ABW[化学式：见正文]簇最稳定结构的气相结合能。DFT泛函以DLPNO - CCSD(T)/CBS为基准进行评估。我们发现三种最合适的DFT泛函按以下顺序排列：PW6B95D3 > MN15 > [化学式：见正文]B97XD。因此，建议使用PW6B95D3泛函进一步研究对氨基苯甲酸 - 水簇及类似体系。
探索首先进行经典分子动力学模拟，然后在PW6B95D3/def2 - TZVP理论水平上进行完全优化。使用高斯16代码套件进行优化。使用AIMAll程序进行QTAIM分析。
