On-off-on relay fluorescence recognition of ferric and fluoride ions based on indicator displacement in living cells.

On-off-on relay fluorescence recognition of ferric and fluoride ions based on indicator displacement in living cells.
Anal Chim Acta. 2019 Aug 20;1066:112-120
Authors: Selvaraj M, Rajalakshmi K, Nam YS, Lee Y, Song JW, Lee HJ, Lee KB
Abstract
A new boronic acid derivative functionalized with a 4-(3-(4-(4,5-diphenyl-1H-imidazole-2-yl)phenyl)-1,2,4-oxadiazol-5-yl)phenyl (IOP) moiety was synthesized for use as a sequential "on-off-on"-type relay fluorescence probe for Fe3+ ions and F- ions with high selectivity and sensitivity under physiological conditions. The introduction of Fe3+ to IOP boronic acid (IOPBA) formed an Fe3+IOPBA complex, which led to quenching of the blue fluorescence intensity at 458 nm. The lowest-energy conformation of IOPBA was theoretically predicted to adopt an extended structure, and the Fe3+ ion in the Fe3+IOPBA complex was coordinated to two phenyl groups to form a π-complex. Upon addition of F- to the Fe3+IOPBA complex, the original fluorescence was recovered due to formation of [FeF6]3‒, resulting in "on-off-on"-type sensor behavior. IOPBA showed high selectivity towards Fe3+ among other cations. Moreover, the Fe3+IOPBA complex showed specific selectivity towards F-, with other cations and anions not interfering with detection. Both sensing processes showed 1:1 stoichiometry with binding constants of 6.87 × 106 and 4.49 × 106 mol-1 L for Fe3+ with IOPBA and F- with Fe3+IOPBA, respectively....

Source: Analytica Chimica Acta - April 29, 2019 Category: Chemistry Authors: Selvaraj M, Rajalakshmi K, Nam YS, Lee Y, Song JW, Lee HJ, Lee KB Tags: Anal Chim Acta Source Type: research