Benzimidazole-Based Fluorophores and Noncovalent Organic Frameworks
The previous studies of molecular cruciforms based on distyrylbis(arylethynyl)benzenes, tetrakis(arylethynyl)benzenes, tetrakis(alkynyl)ethenes, and benzobisoxazole cruciforms, and their use as chemical sensors will be introduced and summarized. We construct a simpler "half cruciform" architecture with benzimidazole core, namely L-shaped benzimidazole fluorophores. These fluorophores showed separate frontier molecular orbitals in donor–acceptor systems, similar to benzobisoxazole cruciforms. They display change in their fluorescent emission upon exposure to bases, acids and small anions. The preparation of other benzimidazole-based sensor precursors and initial study is also included. A new class of cruciform based on the benzobisimidazole central motif is introduced together with their synthesis and computational evaluation. These benzobisimidazole cruciforms exhibit strong optical responses to bases, albeit negligible to acids. A representative cruciform was examined and showed pronounced colorimetric response to anions. Noncovalent organic frameworks are porous materials; their porosity results from noncovalent interactions. The series of perfluorinated precursors was synthesized and crystalized to obtain desired noncovalent organic frameworks. The porous framework was analyzed by porosity measurement, single and powder X-ray diffractions.
Cruciform molecules, Noncovalent organic frameworks, Fluorescence, Sensing
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