【作者】 李志锋； 朱元成； 李会学； 唐慧安； 刘新文； 左国防；

【Author】 LI Zhi-Feng,Zhu Yuan-Cheng,LI Hui-Xue,Tang Hui-An,LIU Xin-Wen,ZUO Guo-Fang College of Life Science and Chemistry,Tianshui Normal University,Tianshui 741001

【机构】 天水师范学院生命科学与化学学院；

【摘要】 在B3LYP/6-311++g（d,p）水平上对H2O与HX（X=F,Cl,Br）分子间形成的（H2O）2HX六元环状氢键复合物的构型进行了全优化.频率计算表明,体系中O1-H3,O4-H6及X7-H8的伸缩振动频率均发生红移.氢键H2O¹…HCl,H2O¹…HBr及H2O…H2O的振动频率与文献相符.在MP2/6-311++g（d,p）水平上计算了体系的相互作用能,并利用Kitaura-Morokuma方法对作用能进行了分解.计算得到（H2O）2HCl和（H2O）2HBr体系经BSSE校正的总相互作用能分别为-50.1和-46.6 kJ·mol^-1,与文献值-55.3和-50.1 kJ·mol^-1一致.NBO分析表明,由于复合物分子中的直接超共轭作用,使体系中形成了一H2O¹→HX→H2O²→H2O¹的环形电子流,六元环的形成,增加了其稳定性.由于直接超共轭"拉长"效应较重杂化"收缩"效应占优势,导致了复合物中O1-H3,O4-H6及X7-H8键有所拉长.AIM理论分析表明,复合物中O1…H8,H3…O4及H6…X7之间均存在键临界点,Laplacin量▽2ρ（r）均大于零,表明相互作用具有离子键的特征,这也和利用自然键共振理论（MRT）计算得到的氢键键序值一致.更多还原

【Abstract】 The optimized stable six-ring hydrogen bond complexes between H₂O and HX（X=F,Cl,Br） were found on the potential energy surface by means of B3LYP/6-311++g（d,p）.The obvious red shifts of the O1-H3, O4-H6 and X7-H8 stretching vibrational frequencies in the three complexes were obtained via frequency analysis.Also,the calculated of hydrogen bond stretching vibrational frequencies of H₂O^（1）…HCl,H₂O^（1）…HBr and H₂O…H₂O are consistent with that reported in literature.The hydrogen bond interaction energy were calculated with basis set superposition error（BSSE） correction via counterpoise procedure（CP） method in the MP2/6-311++g（d,p） and the interaction energy were decompose by Kitaura-Morokuma method.The calculated total interaction energy of（H₂O）₂HCl and（H₂O）₂HBr complex are -50.1 and -46.6 kJ·mol^-1 respectively,which consistent with the -55.3 and -50.1 kJ·mol^-1 reported in literature.Natural bond orbital （NBO） theory analysis showed that intermolecular hyperconjugation in the complexes lead to a circle electron transferring[H₂O^（1）→HX→H₂O^（2）→H₂O^（1）],which make the complexes more stable.In complexes, hyperconjugative interaction is more important than the rehybridization,which leads to the O1-H3,O4-H6 and X7-H8 bond are elongated.The topological properties of the hydrogen bond structures were also investigated by the atoms-in-molecules（AIM） theory,and the results showed that there are critical points in O1…H8,H3…O4 andH6…X7 bond.The▽₂ρ（r） of O1…H8,H3…O4 and H6…X7 bond are positive which indicate that the bond possess ionic characters,which also consistent with the results of bond order analysis with natural resonance theory（NRT）。更多还原