氟代芳基碳酸酯与氨基甲酸酯中氢键的理论研究

C -H…F -C HYDROGEN BONDS IN MOLECULAR CRYSTAL OF FLUORINATED ARYL BISCARBONATES AND BISCARBAMATE：A STUDY BASED ON AIM AND NBO ANALYSES

运用 AIM理论在 B97D 水平上计算了2-丁炔-1，4-二基二（2，3，4，5，6-五氟苯基碳酸酯）1，2-丁炔-1，4-二基二（4-氟苯基碳酸酯）2及2-丁炔-1，4-二基二（2，3，4，5，6-五氟苯氨基甲酸酯）3中的分子间有机氟 C -H…F -C 氢键．这些分子间氢键为闭壳相互作用．尽管晶体1中 H…F 距离接近经典氢键，但是该有机氟氢键仍为弱氢键．NBO 分析表明，研究的有机氟 C -H…F -C 氢键存在明显的电荷转移，用电荷转移合理地解释了分子1采取顺式结构．

The intermolecular C-H…F-C hydrogen bonds in crystalline but -2 -yne -1 ,4 -diyl bis（2, 3,4,5,6 -pentafluorophenylcarbonate）1 ,but -2 -yne -1 ,4 -diyl bis（4 -fluorophenylcarbonate）2,and but -2 -yne -1 ,4 -diyl bis（2,3,4,5,6 -pentafluorophenylcarbamate）3 are characterized by using AIMtheory at the B97D level.Criteria based on a topological analysis of the electron density were applied.These intermolecular C-H…F-C hydrogen bonds present typical properties of closed -shell interaction.Our study revealed that organic fluorine hydrogen bond in crystalline 1 is still weak although the distance of H…F is extremely short.NBO analyses indicate that charge transfer （nF→σ＊C-H）is significant even for such weak C-H…F-C hydrogen bonds.The significantly large stabilizing role of charge transfer in crystalline 1 compared with 2,3 gives an explanation for the syn -conformation of organic molecule 1 .