Benzimidazole-Based Fluorophores and Noncovalent Organic Frameworks

Date

2015-12

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Abstract

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.

Description

Keywords

Cruciform molecules, Noncovalent organic frameworks, Fluorescence, Sensing

Citation

Portions of this document appear in: Saeed, Musabbir A., Ha TM Le, and Ognjen Š Miljanić. "Benzobisoxazole cruciforms as fluorescent sensors." Accounts of chemical research 47, no. 7 (2014): 2074-2083. And in: Lirag, Rio Carlo, Ha TM Le, and Ognjen Š. Miljanić. "L-shaped benzimidazole fluorophores: synthesis, characterization and optical response to bases, acids and anions." Chemical Communications 49, no. 39 (2013): 4304-4306. And in: Le, Ha TM, Nadia S. El-Hamdi, and Ognjen Š Miljanić. "Benzobisimidazole Cruciform Fluorophores." The Journal of organic chemistry 80, no. 10 (2015): 5210-5217.