Theoretical Calculation into the Structures and MD Simulation of CL‐20/DNDA5 Cocrystal

Abstract

For studying the cocrystal cell structure and molecular dynamics (MD) simulation of CL‐20/DNDA5 (2,4‐dinitro‐2,4‐dinitropentane), cocrystal construction is predicted on ten kinds of space group of crystal cell. MD simulations are performed at the temperatures of 203, 223, 253, 273, 303, and 323 K. The results show that the cell parameters belonging to P21/C are similar to those of CL‐20/DNDA5 cocrystals which are prepared in the lab. With the decrease of temperature, the energy decreases by about 17.7 kcal mol–1 for every 1 K decrease on average. The radial distribution function shows that the main driving force for the formation of CL‐20/DNDA5 cocrystal is mainly the hydrogen bond formed by H provided by CL‐20 and O provided by DNDA5, the van der Waals force and other hydrogen bonds play an auxiliary role. The Hirshfeld surface analysis shows that the contribution of the CL‐20/DNDA5 O···H to the contact point at Hirshfeld surface is 4.5% higher than that of CL‐20 and the nitro of DNDA5 has the stronger electron donating ability. The morphology of cocrystal growth shows that both the simulated ideal crystal morphology and the single crystal prepared by the experiment belong to prismatic crystal.