A new sensor for the fluorescent and colorimetric detection of CO(2) is described. The system utilizes fluoride to activate a tetrapropyl benzobisimidazolium salt and operates in the absence of an exogenous base. On the basis of spectroscopic and theoretical analyses, the mode of action of the present system is ascribed to the fluoride-induced formation of an N-heterocyclic carbene intermediate that reacts with CO(2) to form an imidazolium carboxylate.

New 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives (1 and 2) were synthesized as an "off-on" fluorescent chemosensor and fluorescent chemodosimeter for Cu2+ and Pb2+. Compound 1 displayed selective and large chelation enhanced fluorescence effects with Pb2+ and Cu2+ among the metal ions examined. On the other hand, compound 2, a fluorescent chemodosimeter, effectively recognized Cu2+ via a selective hydrolysis of the acetyl group.

[Structure: see text]. This study demonstrated that Zinpyr-1*Zn2+ acts as a fluorescent and colorimetric sensor for pyrophosphate at pH 7.4. In addition, Zinpyr-1*Cu2+ and DIARB-1*Cu2+ complexes were found to act as selective fluorescent sensors for pyrophosphate. Furthermore, the chemosensors Zinpyr-1*Zn2+ and Zinpyr-1*Cu2+ show highly selective and ratiometric fluorescence changes for pyrophosphate compared with H2PO4-.

Quinoxaline derivatives (1−4) bearing two imidazolium moieties are found to strongly bind anions and show unique charge-transfer fluorescent responses to pyrophosphate and acetate, whereas they show excimer formation with other anions. Anion-binding studies are investigated with fluorescence and 1 H NMR analysis, single-crystal X-ray analysis, and theoretical calculations.Anions play a fundamental role in a wide range of chemical and biological processes, and numerous efforts have been devoted to the development of abiotic receptors for anionic species. 1 Sensors based on anion-induced changes in fluorescence 2 and intramolecular/intermolecular excimer formation 3 appear to be particularly attractive. On the other hand, given that carboxylic acids (or carboxylates) are a common functional group in biological and synthetic organic molecules, the development of simple to sophisticated receptors for carboxylates has attracted immense attention. 4 The imidazolium group can make a strong interaction with anions through the (C-H) + -X --type ionic hydrogen bond-ing involving the dominating charge-charge electrostatic interaction 5 which is in contrast to well-known neutral receptors involving typical hydrogen bonding for the anion