The π-stacking effects of benzene ring (Ben) with 1H- and 2H-tetrazole derivatives (1H-TZ-X and 2H-TZ-X) substituted at C5 have been evaluated by computational quantum chemistry methods.

The results indicate the 1H-TZ-X||Ben complexes are more stable than 2H-TZ-X||Ben while in unstacked forms, 1H-TZ-X is less stable than 2H-TZ-X.

All substituents enhance the stacking interactions relative to the unsubstituted case, where enhancement is higher for electron-withdrawing substituents.

Two correlation equations were found for prediction of the ∆E values of the 1H-TZ-X||Ben and 2H-TZ-X||Ben complexes.

The π-stacking interaction increase the basicity and the H-bonding capacity of 1H-TZ-X and 2H-TZ-X. This increase is accompanied by increase in the electrostatic interactions.