Theoretical investigation on the non-covalent interactions of acetaminophen complex in different solvents: study of the enhancing effect of the cation-π interaction on the intramolecular hydrogen bond

In the current research, a comprehensive study is performed on the non-covalent interactions of the acetaminophen complex in the presence of various solvents. In addition, the effect of cation-pi interaction on the strength and nature of the intramolecular hydrogen bond (H-bond) is explored by density functional theory method. The computations are performed using the M06-2X functional and the 6-311++G(d,p) basis set. The obtained results reveal that both interactions become stronger in the gas phase with respect to the solution phase. The "atoms in molecules" theory and the natural bond orbital method are also applied to get more details about the investigated interactions character. Based on the achieved outcomes, the H-bond of the studied complex is placed in the weak H-bond category. Our findings indicate that the intramolecular H-bond is strengthened by the cation-pi interaction in the different solvents. Finally, the physical properties such as frontier molecular orbitals, energy gap, dipole moment, chemical hardness as well as electronic chemical potential are investigated to evaluate the electronic properties, stability and reactivity of the studied complex.