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A selective chemosensor and fluorescence probe for relay recognition of cations and fluoride ions in aqueous media with logic gate function

Arabahmadi, Raziyeh
Talanta 2019 v.194 pp. 119-126
absorption, cations, cobalt, copper, emissions factor, fluorescence, fluorescence emission spectroscopy, fluorescent dyes, fluorides
Cation to anion relay recognition was studied for the first time with sequential specificity (Cu2+ → F− or Co2+ → F−) using a fluorescence “ON−OFF−ON” mechanism. L1 is a receptor with high selectivity for F−, Cu2+ and Co2+ ions in the solution of DMSO/H2O with a 9:1 vol ratio. Absorption and fluorescence spectra were used to investigate the sensing process. Fluorescent emission intensity of L1 at 324 is quenched (switch-Off) after the addition of Cu2+ and Co2+. Surprisingly, complex L1 + Cu2+ or L1 + Co2+ is restored with addition of F− into the compound (switch-On). Consequently, implication (from emission) and inhibit (from absorption) logic gates are constructed at molecular level. The gates operate in fluorescence and absorption modes when Cu2+ and F− or Co2+ and F− are used as input materials and the fluorescence intensity signal as outputs. Based on reversible and reproducible system, a sequential memory unit with integrated ‘‘Writing–Reading–Erasing–Reading’’ behavior, is developed.