Effects of B and N doping/codoping on the adsorption behavior of C60 fullerene towards aspirin: A DFT investigation

The adsorption behavior of pure, B-doped, N-doped, and BN-codoped C60 fullerenes towards an aspirin (AS) molecule is investigated using density functional theory calculations. The formation energies of C59B, C59N and C58BN fullerenes are found to be negative, suggesting that the B and N atoms may be stably inserted in C60. The AS molecule is found to be weakly adsorbed on C60, with no noticeable electron density rearrangement on the interacting units. The adsorption energies of AS on C59B, C59N and C58BN fullerenes, on the other hand, are −1.04, −0.41 and −0.96 eV, suggesting that the introduction of B and N impurities enhances AS adsorption. According to the electron density analysis, the B-O bond formed between the AS and C59B or C58BN is partially covalent, whereas the interaction of the AS with C60 and C59N is mainly electrostatic. Moreover, solvent effects tend to reduce the adsorption energies of the AS molecule, resulting in shorter desorption times for the adsorbed AS molecule. The moderate adsorption energies, high sensitivity, and short desorption times demonstrated that the C59B and C58BN heterofullerenes may be used as efficient delivery vehicles for AS molecules.