An Ultimate Investigation on the Adsorption of Amantadine on Pristine and Decorated Fullerenes C59X (XSi, Ge, B, Al, Ga, N, P, and As): A DFT, NBO, and QTAIM Study

In this investigation, the feasibility of detecting the amantadine (AMD) molecule onto the outer surface of pristine fullerene (C60), as well as C59X (X=Si, Ge, B, Al, Ga, N, P, and As) decorated structures, was carefully evaluated. For achieving this goal, a density functional theory level of study using the HSEH1PBE functional together with a 6-311G(d) basis set has been used. Subsequently, the B3LYP-D3, wB97XD and M062X functionals with a 6-311G(d) basis set were also employed to consider the single point energies. Natural bond orbital (NBO) and the quantum theory of atoms in molecules (QTAIM) were implemented using the B3LYP-D3/6-311G(d) method and the results were compatible with the electronic properties. In this regard, the total density of states (TDOSs), the Wiberg bond index (WBI), natural charge, natural electron configuration, donor-acceptor NBO interactions, and the second-order perturbation energies are performed to explore the nature of the intermolecular interactions. All of the energy calculations and population analyses denote that by adsorbing of the AMD molecule onto the surface of the considered nanostructures, the intermolecular interactions are of the type of strong physical adsorption. Among the doped fullerenes, Ge-doped structure has very high adsorption energy compared to other elements. Generally, it was revealed that the sensitivity of the adsorption will be increased when the AMD molecule interacts with the decorated fullerenes and decrease the HOMO-LUMO band gap; therefore, the change of electronic properties can be used to design suitable nanocarrier. The feasibility of detecting the amantadine molecule onto the outer surface of pristine fullerene, as well as C59X (X = Si, Ge, B, Al, Ga, N, P, and As) decorated structures, was carefully evaluated. Various analyses such as the total density of states, the Wiberg bond order, natural bond orbital, noncovalent interaction, and quantum theory of atom in molecule were performed to shed light on the nature of intermolecular interactions. Results show that the change in electronic properties can be used to design suitable nanocarrier.