Selvarengan Paranthaman, Kolandaivel Ponmalai Gounder
Department of Physics, Bharathiar University, 641 046, Coimbatore, India.
J Mol Model. 2004 Jun;10(3):198-203. doi: 10.1007/s00894-004-0184-y. Epub 2004 Mar 16.
Intermolecular hydrogen-bond interactions in the monohydrated complexes of formamide, N-methylacetamide and glycylglycine have been studied using ab initio and DFT methods. The geometries were optimized using second-order Møller-Plesset perturbation theory and the B3LYP DFT functional with the 6-311++G** basis set. It is observed that hydrogen-bond interactions at the carbonyl group of the peptide moiety are stronger than those at the amino group of the formamide and N-methylacetamide molecules. Because of the presence of cyclic hydrogen-bonding interactions in glycylglycine, the interaction at the amino group is higher than at the carbonyl. The 13C and 15N NMR shielding values were calculated for the non-hydrated and monohydrated complexes. Condensed Fukui functions have also been calculated for non-hydrated formamide, N-methylacetamide and glycylglycine molecules at the B3LYP/6-311++G** level of theory, and the results are discussed.
已使用从头算和密度泛函理论（DFT）方法研究了甲酰胺、N-甲基乙酰胺和甘氨酰甘氨酸一水合物配合物中的分子间氢键相互作用。使用二阶Møller-Plesset微扰理论和具有6-311++G基组的B3LYP DFT泛函对几何结构进行了优化。观察到肽部分羰基处的氢键相互作用比甲酰胺和N-甲基乙酰胺分子氨基处的氢键相互作用更强。由于甘氨酰甘氨酸中存在环状氢键相互作用，氨基处的相互作用高于羰基处。计算了非水合和一水合配合物的13C和15N NMR屏蔽值。还在B3LYP/6-311++G理论水平上计算了非水合甲酰胺、N-甲基乙酰胺和甘氨酰甘氨酸分子的凝聚福井函数，并对结果进行了讨论。
