Mu Xiaojiao, Wang Qiantao, Wang Lee-Ping, Fried Stephen D, Piquemal Jean-Philip, Dalby Kevin N, Ren Pengyu
Department of Biomedical Engineering, ‡Division of Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin , Texas 78712, United States.
J Phys Chem B. 2014 Jun 19;118(24):6456-65. doi: 10.1021/jp411671a. Epub 2014 Feb 20.
The charge distribution of halogen atoms on organochlorine compounds can be highly anisotropic and even display a so-called σ-hole, which leads to strong halogen bonds with electron donors. In this paper, we have systematically investigated a series of chloromethanes with one to four chloro substituents using a polarizable multipole-based molecular mechanics model. The atomic multipoles accurately reproduced the ab initio electrostatic potential around chloromethanes, including CCl4, which has a prominent σ-hole on the Cl atom. The van der Waals parameters for Cl were fitted to the experimental density and heat of vaporization. The calculated hydration free energy, solvent reaction fields, and interaction energies of several homo- and heterodimer of chloromethanes are in good agreement with experimental and ab initio data. This study suggests that sophisticated electrostatic models, such as polarizable atomic multipoles, are needed for accurate description of electrostatics in organochlorine compounds and halogen bonds, although further improvement is necessary for better transferability.
有机氯化合物上卤素原子的电荷分布可能具有高度各向异性，甚至会呈现出所谓的σ-空穴，这会导致与电子供体形成强卤素键。在本文中，我们使用基于可极化多极矩的分子力学模型，系统地研究了一系列具有一到四个氯取代基的氯甲烷。原子多极矩准确地再现了氯甲烷周围的从头算静电势，包括在氯原子上具有显著σ-空穴的四氯化碳。将氯的范德华参数拟合到实验密度和汽化热上。计算得到的几种氯甲烷同二聚体和异二聚体的水合自由能、溶剂反应场和相互作用能与实验数据和从头算数据吻合良好。这项研究表明，对于准确描述有机氯化合物中的静电作用和卤素键，需要复杂的静电模型，如可极化原子多极矩，尽管为了获得更好的转移性还需要进一步改进。
