A DFT study of penicillamine adsorption over pure and Al-doped C60 fullerene

This study considers the effects of penicillamine adsorption over structural and electronic properties of pure and Al-doped C-60 fullerene in the gas phase using density functional theory (DFT) calculations. Our calculations demonstrate that penicillamine is weakly adsorbed on pure C-60 fullerene with a binding energy (E-b) of - 0.12 eV by B3LYP and - 0.13 eV by B3PW91 functional. Both electronic and structural properties were explored in terms of dipole moment, binding energies, and frontier molecular orbitals. In contrast to pristine C-60, the binding energy of the Al-C-60-NH2 complex is much stronger and HOMO-LUMO energy gaps are slightly reduced. The values of global hardness, HOMO-LUMO energy gap, and ionization potential of Al-doped C-60-drug (NH2 group) are decreased and cause lowering of stability and increase in reactivity of the complex. Our results suggest that doping may improve drug delivery capacity of C-60 fullerene.