Synthesis, application and AIE properties of novel fluorescent tetraoxocalix[2]arene[2]triazine: The detection of a hazardous anion, cyanate

Fluorescent cyclophanes and their applications

With the serendipitous discovery of crown ethers by Pedersen more than half a century ago and the subsequent introduction of host-guest chemistry and supramolecular chemistry by Cram and Lehn, respectively, followed by the design and synthesis of wholly synthetic cyclophanes-in particular, fluorescent cyclophanes, having rich structural characteristics and functions-have been the focus of considerable research activity during the past few decades. Cyclophanes with remarkable emissive properties have been investigated continuously over the years and employed in numerous applications across the field of science and technology. In this Review, we feature the recent developments in the chemistry of fluorescent cyclophanes, along with their design and synthesis. Their host-guest chemistry and applications related to their structure and properties are highlighted.

Ru(II)-Catalyzed Regioselective C-N Bond Formation on Benzothiazoles Employing Acyl Azide as an Amidating Agent

A Ru(II)-catalyzed regioselective direct ortho-amidation of 2-aryl benzo[d]thiazoles employing acyl azides as a nitrogen source has been accomplished. This approach utilizes the efficiency of benzothiazole as a directing group and the role of acyl azide as an effective amidating agent toward C-N bond formation, thereby evading the general Curtius rearrangement. The protocol highlights significant functional group tolerance, single-step, and external oxidant-free conditions, with the release of only innocuous molecular nitrogen as the byproduct. The reaction mechanism and the intermediates associated with this selective Ru-catalyzed reaction have been investigated using ESI-MS. The protocol also aided in the construction of ortho-amidated β-carbolines, unveiling another class of fluorescent molecules.

Cyanobiphenyl-spiropyrane and -hemicyanine conjugates for cyanide detection in organic/aqueous media through reverse ICT direction: Their practical applications

Cyanide is one of the most known toxic substances. It is used in many industries and threats human health and environment through releasing with wastewater. Therefore, it is very important to detect its accurate amount, rapidly. Herein, turn-on and turn-off fluorescence sensors of hybrid cyanobiphenyl-spiropyrane and -hemicyanine were developed for the detection of CN^- ions on the basis of nuchleophilic addition to indolium moiety. Detection behavior of the both probes toward a series of anions was investigated by means of fluorescence, UV-vis, NMR and TOF-MS techniques. The results obviously indicate that both probes show remarkable spectral changes and high selectivity toward CN^- with respect to other tested anions. Cyanide levels in water samples up to 0.208 μM could be quantitatively detected as practical application. A smartphone imaging application was successfully constructed for CN^- detection. Noticeably, production of cotton kids and PSF capsules revealed that the probe could be conveniently used for on-site measurement of cyanide without complicated instruments.