Competitive Interactions in the Crystal Structures of Benzils Effected by Different Halogen Substitution

To understand the consequences of halogen substitutions on the crystalline packing behavior of benzils, benzil itself and its derivatives with fluorine, chlorine, bromine, and iodine substituents in the p-position of the phenyl rings were studied and compared with respect to their crystal structures, which are new for the chloro, bromo, and iodo derivatives. While the molecular structures in the crystal are relatively unaffected by the substitution, this is not the case for their packing. In particular, in the chloro, and seemingly in some weaker tendency also in the bromo and iodo derivatives, a leading influence of the halogen atoms to cause specific halogen···halogen contact modes is shown, whereas the influence of the fluorine atom is minor.为探究卤素取代对苯偶酰（benzil）晶体堆积行为的影响，本研究以苯偶酰本身及其苯环对位带有氟、氯、溴、碘取代基的衍生物为研究对象，针对其晶体结构开展研究并进行对比分析——其中氯代、溴代及碘代衍生物的晶体结构均属首次报道。尽管晶体中的分子结构受取代基影响相对有限，但取代基对晶体堆积模式的影响则截然不同。具体而言，氯代衍生物中卤素原子对形成特定卤素-卤素接触模式具有主导作用，溴代与碘代衍生物亦呈现出较弱的此类趋势，而氟原子的影响则相对微弱。