摘要
运用量子化学从头算方法研究了复合物C5H5N…CHX3(X=F,Cl,Br,I)分子间C—H…N和C—H…π氢键.研究表明,在MP2/SDD水平下,分子间C—H…N氢键的形成均使CHX3分子中C—H键伸长,伸缩振动频率减小,形成红移氢键;分子间C—H…π氢键的形成均使CHX3分子中C—H键收缩,伸缩振动频率增大,形成蓝移氢键.振动光谱分析表明,不能根据质子供体分子CHX3的固有偶极矩对C—H键长的导数来判断红移氢键和蓝移氢键.NBO分析表明,超共轭效应占优势,因此形成C—H…N红移氢键;重杂化效应占优势,因此形成C—H…π蓝移氢键.
Ab initio quantum chemistry method was employed to investigate the intermolecular C—H…N and C-H…π interaction between pyridine and CHX3（X=F,Cl, Br or I）. The results showed that at MP2/SDD level, for the C-H…N interaction, classical H-bonds were formed with an elongation of C-H and a red shift,while for the C-H…π interaction,blue shifting H-bonds were identified with a contraction of C—H and a blue shift.Vibrational spectral analysis indicated that the derivative of permanent dipole moment with respect to C—H stretch of the proton donor alone was not sufficient to determine whether blue shifting or red shifting H-bonds were formed.NBO analysis showed that the competition between hyperconjugation and rehybridization resulted in the two kinds of H-bonds.
出处
《西南大学学报（自然科学版）》
CAS
CSCD
北大核心
2007年第5期26-30,共5页
Journal of Southwest University(Natural Science Edition)
基金
重庆市自然科学基金资助项目(230413515)
关键词
从头算
红移氢键
蓝移氢键
C—H…N氢键
C—H…π氢键
ab initio calculation
red-shifting H-bond
blue-shifting H-bond
C—H…N interaction
C—H…π interaction
