Lalitha M, Senthilkumar L
Department of Physics, Bharathiar University, Coimbatore 641046, Tamil Nadu, India.
Department of Physics, Bharathiar University, Coimbatore 641046, Tamil Nadu, India.
J Mol Graph Model. 2014 Nov;54:148-63. doi: 10.1016/j.jmgm.2014.10.012. Epub 2014 Oct 27.
A theoretical study to understand the interaction between anion and the water molecules through the hydration (X(-)·(H2O)n (X=OH, NO2, NO3, CO3), where n=1-10), using the density functional theory method with B3LYP functional and 6-311++G(d,p) basis set has been carried out systematically. In these hydrated clusters we notice three different cases of bond arrangements, namely, symmetrical double hydrogen bond, single hydrogen bond and inter-water hydrogen bond. All the complexes are dominated by the O-H⋯O hydrogen bond, in which the anion act as a proton acceptor, while the water molecule act as a proton donor. A linear correlation is obtained between the solvent stabilization energy and the size (n) of the hydrated cluster for all the anions. The weighted average interaction energy values, shows that the water molecules strongly bind with the OH(-) anion. Besides, the solvation of the OH(-) anion requires less number of water molecules when compared with the other anions. Energy decomposition analysis (EDA) shows the strong dominance of the electrostatic energy component within the interaction energy. The total NPA charges on the anions indicate an increase in the solvation due to hydration. From AIM analysis, excellent linear inverse correlation is observed for both the electron density and Laplacian of the electron density with respect to the hydrogen bond length. Natural bonding orbital analysis (NBO) predicts large charge transfer between the OH(-) anion and the water molecules.
采用密度泛函理论方法，使用B3LYP泛函和6 - 311++G(d,p)基组，对阴离子与水分子通过水合作用（X(-)·(H2O)n ，其中X = OH、NO2、NO3、CO3，n = 1 - 10）的相互作用进行了系统的理论研究。在这些水合团簇中，我们注意到三种不同的键排列情况，即对称双氢键、单氢键和水分子间氢键。所有配合物都以O - H⋯O氢键为主，其中阴离子作为质子受体，而水分子作为质子供体。对于所有阴离子，溶剂稳定能与水合团簇的大小（n）之间都获得了线性相关性。加权平均相互作用能值表明，水分子与OH(-)阴离子强烈结合。此外，与其他阴离子相比，OH(-)阴离子的溶剂化所需的水分子数量较少。能量分解分析（EDA）表明静电能分量在相互作用能中占主导地位。阴离子上的总NPA电荷表明由于水合作用溶剂化作用增强。从AIM分析可知，电子密度和电子密度的拉普拉斯算子与氢键长度之间都观察到了极好的线性反比关系。自然键轨道分析（NBO）预测OH(-)阴离子与水分子之间存在大量电荷转移。
