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.