CL-20/FOX-7共晶的分子动力学模拟

依据共晶形成的氢键规则,搭建了7种CL-20/1,1-二氨基-2,2-二硝基乙烯(FOX-7)共晶模型;采用分子动力学(MD)模拟研究了CL-20/FOX-7共晶形成的可能性;通过径向分布函数(RDF)考察了共晶模型内分子的相互作用力;采用X-射线粉末衍射(XRD)模拟分析了共晶模型与纯组分间衍射峰的区别。结果表明,FOX-7和CL-20分子间存在较强的氢键和范德华力,7种共晶模型的结合能大小顺序为:Eb(1 0 1)Eb(1 1-1)E_b(随机晶面)E_b(0 1 1)E_b(0 0 2)E_b(1 1 0)E_b(1 0-1);7种共晶模型的分子间作用力以FOX-7取代CL-20(1 0 1)、(11-1)晶面较强;7种共晶模型的XRD衍射峰相较纯组分CL-20或FOX-7区别较大。据此推测在制备CL-20/FOX-7共晶过程中,FOX-7取代CL-20(1 0 1)晶面的共晶模型易于形成。

Molecular Dynamics Simulation of CL-20/FOX-7 Co-crystal

Seven kinds of models of 2 ,4 ,6 ,8 ,10 ,12‐hexanitro‐2 ,4 ,6 ,8 ,10 ,12‐hexaazaisow urtzitane (CL‐20 ) /1 ,1‐diamino‐2 ,2‐dinitroethylene (FOX‐7) co‐crystals were constructed based on the hydrogen bond rules of co‐crystal formation .The probability of CL‐20/FOX‐7 co‐crystal formation was investigated using the molecular dynamics (MD) simulation .The radical distribution function (RDF) was used to study the acting force between the molecules in co‐crystal model .X‐ray powder diffraction (XRD) was used to simulate and analyze the difference between XRD peaks of co‐crystal models and pure components .The results show that there are strong hydrogen bonds and Van Der Waals forces between CL‐20 and FOX‐7 .The binding energies of seven kinds of co‐crystal models decrease in the order of Eb (1 0 1)> Eb (1 1 -1)> Eb (randomness surface)> Eb (0 1 1)> Eb (0 0 2)> Eb (1 1 0)> Eb (1 0 -1) .The intermolecular forces of seven kinds of co‐crystal models are stronger when some CL‐20 molecules are substituted by FOX‐7 on the surface (1 0 1) and (1 1 -1) .The XRD peaks of seven kinds of co‐crystal models are quite different from that of pure component CL‐20 or FOX‐7 .Therefore ,it can be predicted that CL‐20 molecule is more easily substituted by FOX‐7 on the surface (1 0 1) to obtain the stable co‐crystal structure in the preparation process of the CL‐20/FOX‐7 co‐crystal .