Molecular structure, QTAIM and bonding character of cation–π interactions of mono- and divalent metal cations (Li+, Na+, K+, Be2+, Mg2+ and Ca2+) with drug of acetaminophen

Abstract

The molecular modeling analysis via density functional theory (DFT) calculations is performed on all the formed complexes from interaction between mono- and divalent metal cations (Li+, Na+, K+, Be2+, Mg2+ and Ca2+) with acetaminophen. The interaction energies are calculated by M06-2X method in the gas phase and the solution. The obtained structures are analyzed by topological parameters in terms of electron density (ρ) and its Laplacian (∇2ρ) at the bond critical point (BCP) using the atoms in molecules (AIM) methodology. The evaluated results from calculations suggest that the strongest interaction and the highest electron density at BCP are related to the Be2+ complex. In addition, the natural bond orbital (NBO) analysis is performed to investigate the charge distribution in the related complexes. The MEP (molecular electrostatic potential) is given the visual representation of the chemically active sites and comparative reactivity of atoms. Finally, the quantum molecular descriptors such as energy gap, electronic chemical potential, global hardness and electrophilicity index are calculated to evaluate the electronic properties, stability and reactivity of the analyzed complexes.