Density functional study on covalent functionalization of zigzag graphene nanoribbon through l-Phenylalanine and boron doping: Effective nanocarriers in drug delivery applications

Abstract

The covalent functionalization of zigzag graphene nanoribbon (ZGNR(6,0)) with l-Phenylalanine (C9H11NO2) was investigated by using the first principles-density functional theory (DFT) calculations. The functionalized complex is named as fZGNR. Substitutional doping of boron with respect to edge carbon atom of fZGNR was carried out at three sites viz., near the edge (fbeZGNR), away from the edge (fbaZGNR),centre of the nanoribbon(fbcZGNR).The structural optimization by using the local density approximation and single zeta polarized basis set was carried out.The electronic and chemical properties such as band gap, charge transfer,chemical potential,dipole moment, bond length,binding energy and percentage s orbital character of fZGNR, fbeZGNR, fbaZGNR and fbcZGNR were calculated. Significant structural deformation was exhibited by all the four systems.Moreover, fbeZGNR system exhibits, an increase in chemical reactivity and reduction in kinetic energy of electrons in comparison to the other three systems.Further,the increase in bond dipole moment in fbeZGNR and fbaZGNR systems suggests a higher Gibb’s free energy of solvation in aqueous medium.fbeZGNR is found to be more stable in accordance with the direct correlation between total energy and elecron density. These theoretical studies pave the way for using the functionalized nanoribbon as nanocarriers in targetted drug delivery applications.