氧化石墨烯-环糊精与金刚烷超分子包合体系的计算机模拟

Computer simulation study on supramolecular inclusion complex of graphene oxide-cyclodextrin with adamatane

理论设计了由6位单羟丙基α(β)-环糊精(Cyclodextrin,HPCD)与氧化石墨烯(GrapheneOxide,GO)共价键连接形成的复合主体化合物(GO-HPCD).结合量子化学计算(QM)和分子动力学模拟(MD),系统研究了该复合主体对金刚烷(Adamantane,AD)的超分子包合行为,并与HPCD对AD的包合进行了比较研究.对研究的结果从构型、热力学性质、径向分布函数(RadialDistributionFunction,RDF)等方面进行了全面分析.在气相条件下,B3LYP/6-31G(d,p)计算结果显示,4种主体对金刚烷的相互作用均较弱;HPαCD和GOHPαCD与金刚烷的MD模拟与QM结果一致,而HPβCD和GO-HPβCD能与金刚烷形成稳定的包合物.在水溶剂中,4种主体均能与金刚烷形成包合物,HPβCD和GO-HPβCD与金刚烷的包合物稳定性明显高于HPαCD和GO-HPαCD的包合物.氧化石墨烯片段的引入未改变环糊精与金刚烷的包合本质,但起到了辅助捕获客体分子的作用.

A kind of supramolecular host compound（GO-HPCD） was theoretically designed with graphene oxide（GO） and mono 6-hydroxypropyl-α（β）-cyclodextrin（HPCD） linked together by an ester bond. The supramolecular inclusion behavior of GO-HPCD with adamantane（AD） was systematically investigated using quantum mechanical calculation and molecular dynamics simulation. The inclusion complex of HPCD and AD was also studied as a comparison. The structure, thermodynamic property, and radial distribution function（RDF） of inclusion complexes were discussed in detail. In the gas phase, the B3LYP/6-31G（d,p） calculations showed that the host-guest interactions for all four host compounds were very weak, and the MD simulations of HPαCD and GO-HPαCD with AD gave the same results, while HPβCD and GO-HPβCD could form stable inclusion complexes with AD. In the solvent phase, the AD inclusion complexes of four host compounds were quite stable in water, especially in the case of HPβCD and GO-HPβCD as the host compounds. Furthermore, the AD inclusion properties were unchanged after introducing of GO fragment into the CD host compounds. However, GO fragment could be helpful to capture the guest molecule into the CD cavity.