Fluorinated carbon and boron nitride fullerenes for drug Delivery: Computational study of structure and adsorption

Abstract

We applied a genetic algorithm combined with the B3LYP/6-311G** approach to determine the structures of low-energy isomers of partially fluorinated fullerenes, the number of which is combinatorically huge. We found that the effective interaction of fluorine atoms on the fullerene surface can not be described within the pair approximation with sufficient accuracy. For the smallest C20 fullerene, the most robust bonding with fluorine was observed in the C20F2 isomer, whereas further fluorination was less feasible. For C60 fullerene, the most thermodynamically stable isomers were C60F2 and C60Fm with m about 40. Effective attraction energy of adsorbed fluorine atom with OH, NH2, and COOH functional groups on the C60 fullerene surface is about 1.24 eV. Vibration analysis of the stable C60Fm isomers clarified the fre- quencies shifts during the gradual fluorination. As to fluorinated derivatives of boron nitride cages, some of them possess extreme distortions under low fluorination. However, half- and fully-fluorinated BN fullerenes demonstrate moderate strain and strong van-der-Waals interaction with doxorubicin drug. Loading of doxorubicin on both carbon and boron nitride fullerenes with varying degrees of fluorination confirmed that fluorine concentration defines the energy of the fullerene-drug interaction. A half- fluorinated B12N12F12 cage provides the most substantial adsorption, as the fluorine atoms on its surface are more moveable and can ‘‘adjust” to the DOX molecule. Ó 2022 Elsevier B.V. All rights reserved.

We applied a genetic algorithm combined with the B3LYP/6-311G** approach to determine the structures of low-energy isomers of partially fluorinated fullerenes, the number of which is combinatorically huge. We found that the effective interaction of fluorine atoms on the fullerene surface can not be described within the pair approximation with sufficient accuracy. For the smallest C20 fullerene, the most robust bonding with fluorine was observed in the C20F2 isomer, whereas further fluorination was less feasible. For C60 fullerene, the most thermodynamically stable isomers were C60F2 and C60Fm with m about 40. Effective attraction energy of adsorbed fluorine atom with OH, NH2, and COOH functional groups on the C60 fullerene surface is about 1.24 eV. Vibration analysis of the stable C60Fm isomers clarified the fre- quencies shifts during the gradual fluorination. As to fluorinated derivatives of boron nitride cages, some of them possess extreme distortions under low fluorination. However, half- and fully-fluorinated BN fullerenes demonstrate moderate strain and strong van-der-Waals interaction with doxorubicin drug. Loading of doxorubicin on both carbon and boron nitride fullerenes with varying degrees of fluorination confirmed that fluorine concentration defines the energy of the fullerene-drug interaction. A half- fluorinated B12N12F12 cage provides the most substantial adsorption, as the fluorine atoms on its surface are more moveable and can ‘‘adjust” to the DOX molecule. Ó 2022 Elsevier B.V. All rights reserved.