Organic Salts as Supramolecular Hosts with Various Applications.

Brønsted salts are an integral part of everyday activities in various research areas. This article is on hydrogen-bonded assemblies of host-guest complexes of organic salts referred to as ionic cocrystals. Proton transfer from an organic conjugate acid to a base provides salts, which participate in self-assembly with one or more neutral parent components or guests, providing ionic cocrystals. At first sight, such salts appear like the simplest among all other compounds; they have a large scope as medicine, energy materials, and fertilizers in a native form or as ionic cocrystals. The host systems of Brønsted salts have numerous utilities as materials used in diverse sectors and molecular recognition. The ionic cocrystals have the prospect to control bioavailability, degradation, and specific delivery of one or more components. The compositions and types of salt cocrystals are illustrated to explain the different key structural features. The fundamental issue of their utility in the self-recognition of one of the components is analyzed. Their perspectives on their applications in energy, medicine, the environment, and materials are presented.