Non-Covalent Functionalisation of C-30 Fullerene by Pyrrole-n-Carboxylic Acid (n=2, 3): Density Functional Theory Studies

Abstract

For functionalisation of a representative C-30 fullerene nanostructure by pyrrole-n-carboxylic acid (PnCA; n = 2, 3) their stabilities and properties were investigated based on density functional theory calculations. Parallel calculations were also done for C-60 fullerene as evidence for comparing the results. Non-covalent interactions are considered to make the functionalised structures. In contrast with the spherical shape of C-60, the shape of C-30 fullerene is elliptical; therefore, the functionalisation processes were done for both axial and equatorial elliptical positions (AC30 and EC30). The results indicated that both the positions of C-30 have almost equivalent chances to be functionalised by PnCA; but functionalisation by P2CA is slightly more favourable than P3CA, either for C-60. The illustrated molecular orbitals' distributions indicated that the direction of charge transfer could be considered from PnCA counterparts to fullerene counterparts. The molecular properties indicated more reactivity for C-30 than for C-60 fullerene. Finally, the atomic scale quadrupole coupling constants indicated different roles for N and O atoms of PnCA in the functionalised models.