The Substituent Effects on π-type Pnicogen Bond Interaction

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. The π-type halogen bond was also calculated and comparison of these two π-type interactions was made. It has been revealed that the π-type pnicogen bond systems are more stable than the halogen bond ones. (paper)