同时基于氢键和卤键的尿素含碘衍生物对卤素阴离子的识别机理

The recognition mechanism of the urea-based involving iodine derivation receptor for the halogen anions through combinations of hydrogen bond and halogen bond

采用密度泛函B3LYP(Becke,three-parameter,Lee-Yang-Parr)量子化学理论方法探讨了同时基于氢键和卤键者两种弱相互作用的尿素无氟含碘衍生物对卤素阴离子(F-,Cl-,Br-和I-)的识别机理,结果发现尿素衍生物受体分子A以其结构中的两个N-H键和两个C-I与卤素阴离子间形成四齿弱键进行识别.其中包括2个N-H…X-红移氢键和2个C-I…X-蓝移卤键弱相互作用.另外,经BSSE校正后的A…F-,A…Cl-,A…Br-和A…I-分子识别体系中相互作用能ΔECP分别为-48.90,-121.78,-311.42和-96.55kJ/mol,从结合强度上来看,受体A对Br-和Cl-具有较好的识别能力,而对F-的识别能力相对较弱.此外,采用自然键轨道(NBO)理论分析了C…X-(X=F-,Cl-,Br-和I-)识别体系中红移氢键和蓝移卤键的电子行为与性质.

The recognition mechanism of the urea-based derivation receptor （A） for the halogen anions through combinations of hydrogen bond and halogen bond was discussed at the density function Becke, three-parameter, Lee-Yang-Parr （B3LYP） method. The results showed that recognition mechanism was performed by using four coordination weak bonds between the two N--H and two C--I of the urea-based derivation receptor （A）, which include two red-shift N--H…X hydrogen bonds and two blue-shift C-I…X halogen bonds. The calculated interaction energies （△ECP） with basis set super-position error （BSSE） correction of the four systems are--48.90, -121.78, -311.42 and --96.55 kJ/mol, respec- tively. So, the urea-based derivation receptor （A） presents the best recognition capable for the Br- and Cl-. Natural bond orbital theory （NBO） analysis has been used to investigate the electronic behavior and property of the red-shift N--H…X hydrogen bonds A…X- recognition systems. and two blue-shift C--I…X halogen bonds in the