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

Intermolecular interactions between PH_2Cl and Ar–R(R = H,OH,NH_2,CH_3,Br,Cl,F,CN,NO_2) were calculated by using MP2/aug-cc-p VDZ 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 PH_2Cl 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 PH_2Cl 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.     

3种伞形科濒危药用植物挥发油的化学成分分析与分类学意义

应用GC/MS对我国稀有濒危单型属药用植物明党参、川明参和珊瑚菜根部挥发油的化学成分进行研究,并通过对3种植物共有化学成分进行多种聚类分析,从化学分类学角度定量阐明了3种植物所代表的三属间的亲缘关系与经典分类学相一致.