An Attempt to Design Thermosalient Crystals by Co-Crystallization: The Twisted Angle between Aromatic Rings

Abstract

Thermosalient (TS) crystals have gained considerable attention due to their potential applications in various fields, including in actuators, sensors, energy harvesting, and artificial muscles. Herein, co-crystallization was employed to construct TS crystals by forming a twisted angle between aromatic rings. Two multicomponent trimethoprim (TMP) TS cocrystals, TMP-25HBA and TMP-OA, were obtained. Differential scanning calorimetry (DSC) and variable-temperature powder X-ray diffraction (VT-PXRD) revealed that TMP-OA undergoes a solid-to-solid phase transition, while TMP-25HBA does not exhibit any phase transition. To the best of our knowledge, TMP-25HBA is the first multicomponent TS crystal without phase transition. The TS effect of both crystals is a result of the unit cell’s anisotropic expansion.