Three Types Halogen Bond Interaction Studied Between Pyrazine And XF

Except σ-type and π-type halogen bond, a new type of the parallel halogen bond interactions between pyrazine (C4H4N2) and XF (X=F,Cl,Br and I) have been discovered at the MP2/aug-cc-pVTZ level. Through comparing the calculated interaction energy,we can know that the π-type halogen bonding interactions are weaker than the corresponding σ-type halogen bonding interactions, and parallel halogen-bond interactions are weaker than the corresponding π-type halogen bonding interactions in C4H4N2-XF complexes. SAPT analysis shows that the electrostatic energy are the major source of the attraction for the σ-type halogen bonding interactions while the parallel halogen-bond interactions are mainly dispersion energy. For the π-type halogen bonding interactions in C4H4N2-XF(X=F and Cl) complexes, electrostatic energy are the major source of the attraction, while in C4H4N2-XF(X=Br and I) complexes the electrostatic term, induction and dispersion play equally important role in the total attractive interaction.NBO analysis, AIM theory and Conceptual DFT are also be utilized.

Superalkalis as Building Block for Efficient Lewis Base

In quest for efficient Lewis base an in-silico investigation on NH3 and its structurally similar different molecules have been carried out. It has been observed that the ionization energy of the groups attached to N-centre play an important role in determining their stability and reactivity. Among different groups, superalkali ligands make better Lewis base. Several conceptual DFT descriptors like electrophilicity, nucleophilicity, dual descriptors have been used to analyse the stability and reactivity of proposed Lewis base. Calculated charge transfer descriptor describes the efficiency of the designed Lewis base to form an adduct with Lewis acid. nc-2e (n=1,2) AdNDP calculation lend additional support to the bonding of the studied molecules.