Two new multi-component molecular complexes of cytosine and 5-fluorocytosine with 4-chloro-3,5-dinitrobenzoic acid are presented. Materials synthesis was achieved initially by evaporative crystallisation and the crystal structures determined. The process was then successfully transferred into a controlled small scale cooling crystallisation environment, with bulk samples shown to be representative of the multi-component product phase, by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) methods. Turbidity measurements are shown to be a valuable process analytical technology probe for characterising the initial stages of molecular complex formation in solution. The significance of these findings for scale-up of crystallisation of multi-component molecular materials and for future transfer into continuous cooling crystallisation is discussed.

中文翻译：

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从蒸发结晶到冷却结晶：胞嘧啶及其与4-氯-3,5-二硝基苯甲酸的氟化衍生物的共结晶化研究

提出了两种新的胞嘧啶和5-氟胞嘧啶与4-氯-3,5-二硝基苯甲酸的多组分分子复合物。材料合成最初是通过蒸发结晶实现的，并确定了晶体结构。然后，该过程通过粉末X射线衍射（PXRD）和差示扫描量热法（DSC）成功地转移到受控的小型冷却结晶环境中，散装样品显示出代表多组分产品相的代表。浊度测量显示是一种有价值的过程分析技术探针，可用于表征溶液中分子复合物形成的初始阶段。