Exploring the Polymorphic Accessibility of Halogen-Substituted Dimethyl Isophthalate Derivatives with Green Technology

The influence of halogen-atom substitution for a dimethyl isophthalate compound on the polymorphic behavior and isostructurality property was explored in this paper. Sublimation was demonstrated to exhibit remarkable advantages. Specifically, two polymorphs (Form I and Form II) of dimethyl 5-bromoisophthalate and two polymorphs (Form A and Form B) of dimethyl 5-iodoisophthalate were discovered for the first time. Moreover, the corresponding single crystals suitable for crystal structure determination were also successfully harvested within a few hours. More interestingly, the crystal packing similarities between the stable Form II and metastable Form A were established with the evaluation of quantitative analysis tools. The success in achieving the regulation of luminescence emission with the changes of crystal packing patterns, molecular conformations, and interactions via halogen substitution will provide some inspiration for the development of novel flexible optical solid-state systems in the future.