2-F-环氧丁烷与几种生物小分子间的赝氢键结构

The pseudohydrogen bond structures between 2-F-epoxy-butane and three kinds of bimolecular

采用密度泛函B3LYP(Becke,three-parameter,Lee-Yang-PaH)/6-311++G**和HF(Hartree Fock)/6-311++G**方法,从理论上探讨了2-F-环氧丁烷分别与几种常见而重要的生物小分子咪唑(Iminazole)、噻唑(Thiazole)和恶唑(Oxazo1e)等分子间的弱相互作用,发现分子间同时存在N…H常规氢键和C-F…H-C赝氢键结构.弱相互作用能计算表明3个复合物的相对稳定性相当.计算结果表明,在C-F…H-C赝氢键结构中,与电子的直接供体F密切相关的共价键C-F键长增大,伸缩振动的频率红移,而作为电子受体的H-C基团,其C-H键伸缩振动光谱蓝移;另外,电子密度拓扑性质表明C-F…H-C赝氢键的共价性及离子性均与常规氢键相当.

The weak intermolecular interactions between 2-F-epoxy-butane and Iminazole, Thiazole and Oxazole were theoretically discussed by using density functional B3LYP （Becke, three-parameter, Lee- Yang-Parr）/6-311＋＋G＊＊ and HF （Hartree Fock）/6-311＋ ＋G＊＊ methods. The results showed that both the N…H conventional hydrogen bond and C--F…H--C pseudohydrogen bond （PHB） structures are coexisting in the three complexes. The weak intermolecular interactions energies indicate the relative stabilities of the three complexes are proportionable. The calculated results showed that the stretch vibrational frequency of C-- H bond （electronic acceptor） presents blue shift, but that of C-- F bond, which is intensely related to F group （electronic donor）, presents red shift. Electron density topological properties demonstrates that the covalent and ionic characteristics of the C--F… H--C pseudohydrogen bond are proportional to that of convention hydrogen bond.