QUANTUM MECHANICAL STUDIES ON THE EFFECT OF INTERMOLECULAR ROTATION OF THE STACKING INTERACTION OF DIAZINE ISOMERS

Non-covalent interaction plays an important role in different π-system, aromatic compounds and other biomolecules. The π-π stacking interaction between heteroaromatic systems is an important area of research. Herein, we have taken one simple organic heterocycle such as a diazine molecule and some of its isomers to investigate the π-π stacking interaction. Stacking interactions of heterocycles are highly sensitive towards the position, bond angle and dihedral angle of the heteroatoms and it also results in different interactions for different stacked models. We have chosen the stacked dimers of diazine isomers (1,2-diazine, 1,3-diazine and 1,4-diazine) and quantum mechanical studies have been carried out to compute the π-π stacking interaction using (Møller-Plesset) MPn methods. The diazine isomers show variation in stacking interaction with different intermolecular rotation and we observed a conformational variation in different stacked models of diazine.