Density functional theory calculations at the M06-2X/6-31G** level have been carried out to examine the adsorption behavior of Cladribine drug on the graphene and graphene nanosheets functionalized with different functional groups in water solution. The influence of molecular orientation on the structural properties, adsorption energies, quantum molecular descriptors, and the equilibrium distances has been investigated for studied nanosheets. Considering the results, the nature of drug adsorption on the surface of nanosheets is physical and it turned out that the adsorption energy of the considered complexes has increased by functionalization of the nanosheet. It is observed that the intermolecular hydrogen bonds between Cladribine and the functionalized graphene nanosheets have an influential role in the stability of the physisorption configurations. The negative values of solvation energies illustrate that the solvation of complexes is a spontaneous process and water stabilizes the considered complexes. The quantum theory of atoms has been also applied to investigate the properties of the bond critical points and illustrate closed shell interactions between the Cladribine drug molecule and the nanosheets. The analysis of natural bond orbital revealed that the Cladribine drug is able to be adsorbed on the surface of nanosheets with a charge transfer from the drug molecule to the nanosheets. Consequently, the functionalized graphene nanosheet with epoxide group has improved the interaction between drug molecules and graphene nanosheet with considerable adsorption energy. Therefore, it is concluded that the modified graphene nanosheets can be used as an appropriate carrier for the Cladribine drug molecule.

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研究克拉屈滨抗癌药物在石墨烯和功能化石墨烯上的吸附的 DFT 计算研究

已经进行了 M06-2X/6-31G** 水平的密度泛函理论计算，以检查克拉屈滨药物在石墨烯和水溶液中不同官能团官能化的石墨烯纳米片上的吸附行为。已经研究了分子取向对所研究的纳米片的结构特性、吸附能、量子分子描述符和平衡距离的影响。考虑到结果，纳米片表面的药物吸附性质是物理性质的，结果表明所考虑的复合物的吸附能因纳米片的功能化而增加。据观察，克拉屈滨和功能化石墨烯纳米片之间的分子间氢键对物理吸附构型的稳定性有影响。溶剂化能的负值说明复合物的溶剂化是一个自发过程，水使所考虑的复合物稳定。原子的量子理论也已应用于研究键合临界点的性质，并说明克拉屈滨药物分子与纳米片之间的闭壳相互作用。自然键轨道分析表明，克拉屈滨药物能够吸附在纳米片表面，电荷从药物分子转移到纳米片。最后，具有环氧基团的功能化石墨烯纳米片改善了药物分子与石墨烯纳米片之间的相互作用，具有相当大的吸附能。因此，结论是修饰的石墨烯纳米片可以用作克拉屈滨药物分子的合适载体。