ABSTRACT

The difficulty synthesizing new co-crystals has made the development of efficient methods for screening co-formers a high priority. Co-crystals have been realized as a new generation of materials with tuneable solubility, stability, and performance. Energetic co-formers have exceptionally weak intermolecular interactions making selection of co-crystallization method and parameters critical to forming a true co-crystal. COSMO-RS calculations coupled with the COSMOtherm software suite were used to screen common solvents and co-formers for CL-20. The predicted favorable solvates and co-crystal formers were compared to experimentally confirmed solvates and co-crystals to assess the accuracy of the COSMO method for CL-20-based materials. It was found that screening solvents using excess enthalpy and solvent cavity volume were able to predict experimentally confirmed CL-20 solvates. Co-crystal formation was difficult to predict using the COSMO method, highlighting the importance of entropy and solid-state interactions. The selection of good solvents is perhaps the best method for maximizing entropy. Understanding the dependence on entropy for energetic-energetic cocrystal formation coupled with an accurate method for screening co-crystal formation allows for intelligent design of co-crystallization methods.

摘要

合成新共晶的困难使得开发用于筛选共形成物的有效方法成为重中之重。共晶体已被实现为具有可调溶解度、稳定性和性能的新一代材料。高能共形成物具有异常弱的分子间相互作用，使得选择共结晶方法和参数对于形成真正的共晶至关重要。COSMO-RS 计算与 COSMOtherm 软件套件相结合，用于筛选 CL-20 的常见溶剂和共形成物。将预测的有利溶剂化物和共晶形成物与实验证实的溶剂化物和共晶进行比较，以评估 COSMO 方法对 CL-20 基材料的准确性。发现使用过量焓和溶剂腔体积筛选溶剂能够预测实验证实的 CL-20 溶剂化物。使用 COSMO 方法很难预测共晶形成，突出了熵和固态相互作用的重要性。选择好的溶剂可能是最大化熵的最佳方法。了解高能-高能共晶形成对熵的依赖性，再加上筛选共晶形成的准确方法，可以对共晶方法进行智能设计。