Crystal Engineering with Cocrystals of Benzo-[18]Crown-6 and Urea and Thiourea Derivatives

Cocrystallization experiments were carried out to study the efficacy of Benzo-[18]crown-6 (B18C6) as a cocrystallizing agent (CA). Traditional solution cocrystallization, high-throughput cocrystallization, dry grinding and solvent-drop grinding cocrystallization have led to the discovery of five new cocrystals of B18C6 with urea, thiourea, and their derivatives. The cocrystals have been characterized by a variety of methods, including X-ray diffraction, vibrational spectroscopy (infrared), and optical microscopy (HSM). We have also examined the structures in order to determine the viability and the reproducibility of the R21(6) motif between the donor hydrogen and the ether group of B18C6.