Quantum chemical study on the structural mechanism, π-π* interactions and hydrogen bonding network of 2, 6-diamine-7H-purine molecule: using molecular modeling

Abstract

Molecular structure, electronic and biological properties of 2,6-Diaminopurine (DAP) in the ground state (S0) have been determined by computational approach. The obtained DFT-geometrical parameters are compared with experimental values. The molecular orbital theory provides information about the electron delocalization, and the low value of HOMO-LUMO energies confirms strong charge transfer interactions in the molecular system. The high first order polarizability and hyperpolarizability value estimation of DAP may enhance the biological behavior of the molecule. The chemical properties related to global and local reactivity descriptors are also discussed. Moreover, the molecular electrostatic potential map (MESP) and mulliken atomic charge analysis were carried out. The MEP surface map has been used to calculate the most reactive sites within the complex. NBO analysis was also performed to calculate the strength of hydrogen bonding and stabilization of the chemical substance. The results showed that DAP exhibited strong anti-bonding interactions σ*N3-C4→σ*C5-C6 with a corresponding stabilization energy of 82.02 kcal mol− 1 have been calculated at CAM-B3LYP method. In addition, the QTAIM analysis utilized to calculate the molecular electron density and strong/weak covalent bond interactions in the DAP. Molecular docking analysis was performed to identify the free binding energies and favorable binding pose of the ligand against 1UOM and 1SAO proteins.