The effect of pi-pi stacking interaction on hydrogen bonding in a molecular seesaw balance: A NMR study

We proved by computational NMR data the effect of donating/withdrawing substituents on the A and B complexes in a molecular seesaw balance. The results of investigations were computationally examined by using binding energies, NMR analyse, SAPT decomposition, geomatrical parameters, AIM and NBO analyse at M05-2X/aug-cc-pVDZ level of theory. These substituents affect the stability of optimized complexes so that A and B complexes without substituent (X=H) have minimum binding energies documented the greatest impact of donating/withdrawing substituents. Results show the A complexes is stable than B complexes due to the greater ability of pi-pi stacking between benzene-pyridine rings.