Departamento de Química, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900, Brazil.
Department of Chemistry, Washington State University, Pullman, Washington 99164, United States.
J Phys Chem A. 2021 Jan 14;125(1):198-208. doi: 10.1021/acs.jpca.0c09116. Epub 2021 Jan 5.
We present a benchmark investigation on the O-H bond dissociation enthalpies (BDEs) and ionization potential (IP) for gallic acid (GA), a widely known polyphenolic antioxidant. These properties were determined in the gas-phase and in water through the use of density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2), coupled-cluster with single and double excitations (CCSD), and coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)). The 6-311++G(df,p), cc-pVDZ, aug-cc-pVDZ, cc-pVTZ, and aug-cc-pVTZ basis sets were used. Regarding DFT functionals, the M06-2X provided the best agreement for the BDEs when compared to the corresponding CCSD(T)/aug-cc-pVTZ results; M06-2X was also found to be the most suitable for probing the IP for the protonated forms of GA while LC-ωPBE was the most reliable in the case of deprotonated GA. Given that these properties represent important descriptors for examining mechanisms related to the antioxidant potential of a given polyphenol, we hope that the present work can serve as a guide for computational chemists venturing in the field.
我们对没食子酸（GA）的 O-H 键离解能（BDE）和电离势（IP）进行了基准测试研究，GA 是一种广泛存在的多酚类抗氧化剂。这些性质是通过使用密度泛函理论（DFT）、二级 Møller-Plesset 微扰理论（MP2）、单双激发耦合簇理论（CCSD）和单双激发以及微扰包含三重态的耦合簇理论（CCSD(T)）在气相和水中确定的。使用了 6-311++G(df,p)、cc-pVDZ、aug-cc-pVDZ、cc-pVTZ 和 aug-cc-pVTZ 基组。对于 DFT 泛函，M06-2X 在与相应的 CCSD(T)/aug-cc-pVTZ 结果进行比较时，为 BDE 提供了最佳的一致性；M06-2X 也被发现是探测 GA 质子化形式 IP 的最适合的方法，而 LC-ωPBE 在 GA 去质子化的情况下是最可靠的。鉴于这些性质是检查与给定多酚抗氧化潜力相关机制的重要描述符，我们希望本工作可以为涉足该领域的计算化学家提供指导。
