Cl~–…苯氰…H_2O中阴离子氢键协同效应与芳香性理论研究

A theoretical investigation into the cooperativity effect involving anionic hydrogen bond and aromaticity in Cl~–…benzonitrile…H_2O ternary complex

本文采用DFT-B3LYP和MP2(full)方法对三聚体Cl–…苯氰…H2O中O/C–H…Cl–阴离子氢键与传统氢键O–H…N和C–H…O之间的协同效应、热力学性质以及芳香性进行了研究.结果表明阴离子氢键O/C–H…Cl–对O–H…N或C–H…O相互作用的影响更显著.在线性结构中发生正协同效应,熵变是促进热力学协同效应的主要因素,而在环状结构中发生反协同效应,焓变成为主要因素.在三聚体形成过程中,苯氰环的芳香性是减弱的,而苯氰中π→π*共轭效应是增强的.结果表明,协同效应能Ecoop.分别与Rc(NICS(1)ternary/NICS(1)binary),ΔΔδ(Δδternary-Δδbinary),Rc'((NICS(1)ternary-NICS(1)binary)/NICS(1)binary)和RBDE(C–CN)(BDE(C–CN)ternary/BDE(C–CN)binary)均具有良好的线性关系.同时,AIM的分析也佐证了协同效应的存在.

The cooperativity effects between the O/C - H···Cl^ anionic H -bonding and O - H···N and C - H···O H - bonding interactions, thermodynamic properties and xes are investigated using the B3 LYP and MP2 （full） methods aromaticities in Cl^-··· benzonitrile···H2O comple- The result shows that the influence of the O/C - H···Cl^- anionic H- bonding interaction on the C - H···O is more pronounced than that on the O - H···N in- teraction. The cooperativity effect appears in the linear conformation while the anti -cooperativity effect is found in the cyclic structure. The enthalpy change is the major factor driving the cooperativity in forming the linear ter- nary complex while entropy change turns into the favorable factor in forming the cyclic system. The aromaticity of the benzonitrile ring is weakened and the π→π ＊ conjugative effect between the ring and C≡ N bond is strength- ened upon the ternary - complex formation. To our interest, the cooperativity effect correlates well with Ro （ NICS （l）ternary/NICS （l）binary） , △△δ （△δternary- △δbinary） , Rc＇ （（NICS （1） ternary- NICS （1）binary）/NICS （1）binary） and RBDC（C-CN） （BDE（C-CN）ternary/BDE（C- CN）binary ）, respectively. AIM （atoms in molecules） analysis confirms the existence of cooperativity.