Crystal structure, supramolecular framework, hirshfeld surface analysis, and photophysical studies of some acridinium/acridine derivatives prepared by mechanochemical synthesis

Four acridinium/acridine derivatives have been prepared by mechanochemical synthesis and their crystal structure, supramolecular framework, interaction energy calculation, thermal analysis, and photophysical properties are studied and presented in this manuscript. In the crystal structure, the one- and two-dimensional supramolecular framework is constructed via various strong and weak intermolecular interactions such as N‒H…Cl, O‒H…N, O‒H…Cl, C‒H…Cl, C‒H…O, C‒H…π, and π…π, respectively. The contribution of intermolecular interaction in the three-dimensional molecular packing is studied by the Hirshfeld surface analysis. The calculated total energy value of intermolecular interaction/contacts observed between the molecular pairs in the acridine compound is stronger than the energy value of intermolecular interaction/contacts of acridinium derivatives. The energy value of π…π contacts exhibited between the molecular pairs is significantly stronger than other weak interactions. The thermogravimetric analysis reveals that the acridinium derivatives degrade in three steps whereas the acridine compound undergoes a single-step degradation. Studies show that the acridinium derivatives exhibit a better photoluminescence quantum yield when compared to the acridine compound, and the acridine compound experiences a photoluminescence quenching due to charge transfer interactions.