Adsorption of Folic Acid on the Single-walled Carbon Nanotubes: AIM and NBO Analyses via DFT

In the present work, the behavior of folic acid (FA) molecule adsorbed onto single-walled carbon nanotube (SWCNT) was examined using the DFT-B3LYP/6-31G* level. In order to obtain information about the binding features of SWCNT as adsorbent with FA molecule, several studies, including the structural and electronic parameters and also the Atoms in Molecules (AIM) analysis, were performed. It was observed that the FA molecule via hydrogen bond prefers to adsorb on SWCNT with adsorption energy of about -18.70 kcal/mol. The molecular orbitals (HOMO and LUMO), natural bond orbital (NBO) analysis, and density of states (DOS) plot indicated that a charge about 0.032 vertical bar e vertical bar is transferred from the FA molecule to the nanotube. After solvation energy calculations, it was found that the presence of a polar solvent causes an increase in FA adsorption on the single-walled carbon nanotube. Topological features such as electron energy density (H-C) and Laplacian of the electron density (del(2)rho(c)) demonstrate partial covalent nature for H(116)center dot center dot center dot O(10) interaction in the FA/SWCNT complex. According to the calculated results, the single-walled carbon nanotubes are expected to be a potential efficient adsorbent for the adsorption of folic acid drug and also can be used as a suitable drug delivery vehicle within biological systems.