Density Functional Theory Study of Exohedral Carbon Atoms Effect on Electrophilicity of Nicotine: Comparative Analysis

In recent years, many studies have been done on the structure of fullerene as medicine nano carrier compounds. On this basis, Quantum mechanical calculations have been done and the effect of the nicotine compound in structure of Nanofullerene C₁₂ was studied. Density Functional Theory (DFT) can be used to calculate an accurate electronic structure, HOMO and LUMO energies, Mulliken charge of atoms, energetic orbital levels, global hardness, chemical potential and electrophilicity of systems, and finally chemical, physical properties of fullerene and fullerene derivatives. Theoretical calculations such as Natural Bond Orbital (NBO) are very important to understand the pathways of electron transfer in assemblies. Consequently, the obtained results showed that energy orbital levels decreased considerably by linking structure of Nanofullerene to the structure of Nicotine. The intramolecular interaction is formed by the orbital overlap between C-C, C-N, C-H anti bonding orbital which results an intermolecular charge transfer (ICT) from a Lewis valence orbital (donor), with a decreasing of its occupancy, to a non-Lewis orbital (acceptor). The interacting effect is also discussed in terms of the change in the C-C bond lengths, net atomic charge distribution, total dipole moment. The obtained results indicate that the C-C distances are enlarged interaction. Furthermore, there is a complete change in the net atomic charge distribution, as well as a corresponding increase in the value of the total dipole moment. On the basis of fully optimized ground-state structure, TDDFT//B3LYP/3-21G* calculations have been performed to determine the low-lying excited states of nanofullerene interacting with nicotine (NFN).