Investigation of the Substituent Effects on π-Type Pnicogen Bond Interaction

摘要: Intermolecular interactions between PH2Cl and Ar–R (R = H, OH, NH2, CH3, Br, Cl, F, CN, NO2) were calculated by using MP2/aug-cc-pVDZ quantum chemical method. It has been shown from our calculations that the aromatic rings with electron-withdrawing groups represent much weaker binding affinities than those with electron-donating groups. The charge-transfer interaction between PH2Cl and Ar–R plays an important role in the formation of pnicogen bond complexes, as revealed by NBO analysis. Nevertheless, AIM analysis shows that the nature of the interactions between PH2Cl and Ar–R is electrostatic, and the interaction energies of the complexes are correlated positively with the electron densities in the bond critical points (BCPs). RDG/ELF graphical analyses were performed to visualize the positions and strengths of the pnicogen bonding, as well as the spatial change of the electron localization upon the formation of complexes. The π-type halogen bond was also calculated, and it has been revealed that the π-type pnicogen bond systems are more stable than the halogen bond ones.