Competitive binding of Ba²⁺and Sr²⁺ to 18‐Crown‐6 in a Receptor with a 1‐Methoxyanthraquinone Analogue as the Other Binding Site

Abstract

Owing to their immense biological significance, development of sensors for the selective detection of alkaline earth metal ions has attracted vast research interest. In this article we have reported the synthesis, characterisation and ion binding studies of a new RuII‐polypyridyl‐crown‐anthraquinone complex (5). Studies confirm selective binding of BaII, SrII and CaII ions, with K Ba 2+ > K Sr 2+ >> K Ca 2+, over all other metal ions, to the crown ether moiety and not to the methoxy anthraquinone component, the latter being the second binding site available and known for its affinity towards alkaline earth metal ions from one of our previous reports.

Demonstration of Selective Single-Barium Ion Detection with Dry Diazacrown Ether Naphthalimide Turn-on Chemosensors

“…9,23 Selective barium sensing has been demonstrated by a relatively small number of instructive fluorescent chemosensors. 9,[24][25][26][27][28][29][30][31][32] Barium sensing is not widely studied in clinical settings. Though acute barium exposure can be deadly, diagnoses are rare and often confirmed by inductively-coupled plasma mass spectrometry analysis of patient plasma and urine.…”

“…Selective barium sensing has been demonstrated by a relatively small number of fluorescent chemosensors. ,− This is not surprising because barium sensing is not widely studied for clinical or environmental reasons; although acute barium exposure can be deadly, diagnoses are rare and often confirmed by inductively coupled plasma mass spectrometry analysis of the patient’s plasma and urine. , Nakahara and co-workers pioneered a monoazacryptand receptor with a PET switch to pyrene fluorescence that operates in aqueous micellar systems and would require relatively high-energy excitation that would make SMFI challenging in our system. − Crown ether systems have invoked termolecular complexes with two crown moieties sandwiched around one Ba 2+ , which would also be limited in dry-phase sensing, where bimolecular interactions may be preferred. , A bioinspired G-quadruplex chemosensor provided rapid detection of Ba 2+ , also in solution. , Recently, a fluorescent chemosensor based on the phenoxazine system with an ICT turn-on mechanism was reported for Ba 2+ , where charge transfer was achieved by metal binding specifically to a single amide functional group . These receptors are instructive but unsuitable for long-term dry-phase SMFI device design, presumably as part of a functional monolayer or thin coating deposited on a translucent optical device.…”

Synthesis of Enantiopure P-Stereogenic Diphosphacrowns using P-Stereogenic Secondary Phosphines

“…Spectroscopic data were consistent with those reported in the literature. 21 Synthesis of 4c. Catechol (3.30 g, 30.0 mmol) and K 2 CO 3 (12.4 g, 90.0 mmol) were added to dry CH 3 CN (100 mL).…”

A Dansyl-Rhodamine Ratiometric Fluorescent Probe for Hg2+ Based on FRET Mechanism

“…Fluorimetric sensing is a preferable approach for detection of metal ions or other analytes because fluorimetry is rapidly performed, nondestructive, highly sensitive and suitable for high-throughput screening applications [11][12][13][14]. However, Hg 2+ can quench the luminescence of a fluorophore due to effective spin−orbit coupling mechanism, bound to the receptor functionality of a sensor, and this accounts for the most fluorescence off/quenching-based sensors [15].…”