CH3SH…HOO开壳型氢键复合物的结构及其电子密度拓扑性质  

Structures and Electron Density Topological Properties of the CH_3SH…HOO Hydrogen Bond Complexes

作　　者：刘艳芝[1] 施小宁[1] 李志锋[1] 唐慧安[1] 袁焜[1] 张俊彦[2] 

机构地区：[1]天水师范学院生命科学与化学学院,天水741001 [2]中国科学院兰州化学物理研究所,兰州730000

出　　处：《高等学校化学学报》2009年第10期2049-2054,共6页Chemical Journal of Chinese Universities

基　　金：天水师范学院“青蓝”人才工程基金(批准号:09004);甘肃省教育厅研究生导师科研基金(批准号:070812)资助

摘　　要：在DFT-B3LYP/6-311++G**水平下求得CH3SH…HOO复合物势能面上的稳定构型.计算结果表明,在HOO以其O8—H7作为质子供体与CH3SH分子中的S5原子为质子受体形成的氢键复合物1和2中,O8—H7明显被"拉长",且其伸缩振动频率发生显著的红移,红移值分别为330.1和320.4 cm-1;在CH3SH分子以其S5—H6作为质子供体与HOO的端基O9原子为质子受体形成的氢键复合物3和4中,也存在类似的情况,但S5—H6伸缩振动频率红移不大.经MP2/6-311++G**水平计算的4种复合物含BSSE校正的相互作用能分别为-20.81,-20.10,-4.46和-4.52 kJ/mol.自然键轨道理论(NBO)分析表明,在CH3SH…HOO复合物1和2中,引起H7—O8键长增加的因素包括两种电荷转移,即孤对电子n1(S5)→σ*(H7—O8)和孤对电子n2(S5)→σ*(H7—O8),其中后者为主要作用.在复合物3和4中也有相似的电荷转移情况,但轨道间的相互作用要弱一些.AIM理论分析结果表明,4个复合物中的S5…H7间和O9…H6间都存在键鞍点,且其Laplacian量22ρ(r)都是很小的正值,说明这种相互作用介于共价键和离子键之间,偏静电作用为主.The tour optimized stable CH3SH…HOO hydrogen bond complexes（1-4） were found on the potential energy surface at B3LYP/6-311 ＋ ＋ G^＊＊ level. The calculated results showed that the complexes 1 and 2 use the H7 atom of HOO as proton donor and the S5 atom of CH3SH as acceptor, and the obvious red shifts of the H7-O8 stretch vibration in the two hydrogen bond complexes were obtained by frequency analysis, and the red shift values were 330. 1 and 320.4 cm^-1 , respectively. As for complexes 3 and 4, they use the H6 atom of CH3SH as proton donor and the terminal O9 of HOO as acceptor. The hydrogen bond interaction energies in the four complexes were -20. 81, -20. 10, -4.46 and -4. 52 kJ/mol, which were calculated with basis set superposition error （BSSE） correction at MP2 level. Natural bond orbital （NBO） theory analysis showed that two kinds of charge transfer exist in CH3SH...HOO hydrogen bond complexes 1 and 2： （1） lone pair n^1 （S5） →σ^＊ （H7--O8）, （2） lone pair n^2（S5）→σ^＊ （H7--O8）. Analogous charge transfers existed in eomplexes 3 and 4, but the orbital interactions are weaker. The topological properties of the hydrogen bond structures were also investigated by the atom-in-molecules （AIM） theory, and the results showed that there exist hydrogen bond critical points in four complexes.

关 键 词：甲硫醇 氢过氧自由基 氢键复合物 自然键轨道理论 电子密度拓扑性质 

分 类 号：O641.1[理学—物理化学]