4-碘-2,3,5,6-四氟-甲基苯与3-甲基吡啶、呋喃及丁酮间卤键作用的理论研究

Theoretical Study of Halogen Bonding Between 4-iodo-2,3,5,6-tetrafluoro-methoxybenzene and 3-methylpyridine, Furan and Butanone

在B3LYP/6-311++G**-PP水平上理论计算了三种以卤键结合的组装体,即4-碘-2,3,5,6-四氟-甲氧基苯(PIP)与3-甲基吡啶(MPY)、呋喃(THF)及丁酮(MEK)间卤键结合体的键强度和性质。结果表明,复合物相互作用能从这些PIP…MPY到PIP…MEK逐渐减小,且结构上具有明显的方向性。电荷密度拓扑分析表明,C-I…N(O)属于闭壳层相互作用,键关键点处电荷电荷密度变化与相互作用能趋势一致。自然键轨道理论(NBO)表明,电荷密度从N(O)孤对电子轨道转移到C-Iσ*反键轨道。

The bonding strength and nature of three halogen bonding complexes between 4-iodo-2,3,5,6-tetrafluoro-methoxybenzene(PIP)and 3-methylpyridine(MPY),furan(THF)and butanone(MEK)are investigated at the B3LYP/6-311++G**-PP level.The results show that the interaction energies decrease from PIP…MPY to PIP…MEK gradually.The complexes show highly directional interaction structurally.The electron density topological analysis reveals the interactions in the C-I…N(O)contacts are closed shell interaction in nature,and that the trend of electron density at the bond critical point is consistent with the increase in the interaction energy.Natural bond orbital(NBO)analysis indicates that the electron densities are transferred from the lone pairs of N(O)to theσ*antibonding orbital of C-I bond.