Phototriggered Guest Release from a Nonporous Organic Crystal: Remarkable Single-Crystal-to-Single-Crystal Transformation of a Binary Cocrystal Solvate to a Ternary Cocrystal

Abstract

The development of organic solids for applications in materials science requires a fundamental understanding of how close packing of molecules can affect structure and function. We report here nonporous organic crystals that release entrapped guest molecules upon application of UV light. We show components of binary cocrystal solvates to undergo an intermolecular photoreaction to generate ternary cocrystals that results in release of entrapped solvent molecules. The phototriggered guest release occurs in a single-crystal-to-single-crystal transformation that is in the absence pores and channels in the solid. The cocrystals are composed of a tetratopic hydrogen-bond-acceptor molecule synthesized in the solid state. The UV-light results in [2 + 2] photodimerization of an isocoumarin to generate a ternary cocrystal with cyclobutane molecules that support guest release.

Room-Temperature Magnetic Bistability in a Salt of Organic Radical Ions

“…Relatedly, the cation can influence the geometry of TCNQ –• in the solid state, such that discrete π radical anions and/or its π or σ dimers can be observed in the solid state (Chart ). − In this work, we demonstrate a surprising twofold single-crystal-to-single-crystal transformation − involving both the π and σ dimers of TCNQ –• and discrete TCNQ –• radical anion geometries, leading to thermal bistability at room temperature.…”

Phase-Dependent Reactivity and Host–Guest Behaviors of a Metallo-Macrocycle in Liquid and Solid-State Photosensitized Oxygenation Reactions

“…The development of a method for chemically modifying host compounds by an external stimulus while maintaining the basic skeleton will expand the possibility of designing molecular recognition systems with elaborate functions. − A variety of host molecules with sites that respond to external stimuli such as photoirradiation, − redox reactions, − and certain chemical species − have been extensively developed for molecular switching systems.…”

Multi-step Phase Transformation from Metal–Organic Frameworks to Inorganic Compounds for High-Purity Th(IV) Generation

“…Metal–organic frameworks (MOFs) with clear structure and diversity are now receiving broad attention due to their significant applications in separation, capture, catalysis, and so on. − Sometimes, structure transformation in MOFs can be observed when some external inducers are appended, such as light, heating, solvents, pressure, and chemical reagent. − Most cases in this category often involve the formation of a new bond or breakage of some bond, swing of the skeleton, or conformation change of the organic ligands. , Also, in some cases, the breakage of the coordination bonds was observed, , but in all these examples, the structure transformation does not affect the metal–organic coordination feature. Therefore, further structural degradation may completely induce the breakage of coordination bonds and consequently phase transformation from MOFs to inorganic compounds; this presents a unique scientific issue and could bring new functional materials and innovatory techniques for advanced applications.…”