Papers by Keyword: Weak Bond

Abstract: The recognition mechanism of the urea-based involving Br derivation receptor (A) for the halogen anions through hydrogen bond and halogen bond was discussed by the density function Becke, three-parameter, Lee-Yang-Parr (B3LYP) method. The results showed that the guest-host recognition was performed by using four coordination weak bonds, which include two N-H...X hydrogen bonds and two C-Br...X halogen bonds (X= F^-,Cl^-,Br^- and I^-). The calculated interaction energies (ΔE_CP) with basis set super-position error (BSSE) correction of the four systems are-3.95, -82.43, -70.86 and 992.63 kJmol^-1, respectively. So, the urea-based derivation receptor (A) presents the best recognition capable for the Br^- and Cl^-, and it can not recognize the I^- in the same condition. 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 and two blue-shift C-Br...X halogen bonds in the A...X^- systems.

Abstract: The recognition mechanism of the urea-based non-involving fluorine (A) and involving fluorine (B) derivation receptors for the chlorine anion (Cl-) was discussed by using the density function B3LYP method. The results showed that recognition mechanism was performed by using four coordination weak bonds, which include two N-H…Cl hydrogen bonds and two C-I…Cl halogen bonds. The calculated interaction energies (ΔECP) with basis set super-position error (BSSE) correction of the two systems are -121.78 and -179.71 kJ•mol-1, respectively. So, the urea-based involving fluorine derivation receptor (B) presents the better recognition capable for the Cl-. Natural bond orbital theory (NBO) analysis has been used to investigate the electronic behavior and property of the N-H…Cl hydrogen bonds and two blue-shift C-I…Cl halogen bonds in the A…Cl- and B…Cl- recognition systems, respectively.