A Fluorescent Cobalt Probe with a Large Ratiometric Fluorescence Response via Modulation of Energy Acceptor Molar Absorptivity on Metal Ion Binding

Abstract

Probe 1 has been synthesized as the first ratiometric fluorescent cobalt probe, and it exhibits several highly favorable features, in particular a remarkable ratiometric fluorescence response at two wavelengths. Importantly, the electronic energy transfer (EET) efficiency of the probe is modulated by the energy acceptor molar absorptivity variations on cobalt binding, which then transforms to a large ratiometric fluorescence response at two wavelengths. This signaling mechanism should open a new avenue for the development of powerful ratiometric probes with large emission signal ratios at two wavelengths for exciting applications in many fields.

A novel ratiometric fluorescent Fe3+ sensor based on a phenanthroimidazole chromophore

“…S1) [28,29]. The sensor is effective for detection of 1.0 × 10 −5 to 1.5 × 10 −4 M of Fe 3+ , and the detection limit was calculated as 5.26 × 10 −6 M according to a reported method [26,30,31]. As Fe 3+ ions show significant absorption in the UV/Visible region (Fig.…”

“…The intermediate 2, 4-formylphenyl-2, 2 -bipyridine, was synthesized according to a procedure reported by us [26]. Compound 1 was then readily prepared by reaction of 9,10-phenanthrenequinone with 4-formylphenyl-2, 2 -bipyridine and NH 4 OAc in AcOH based on a similar protocol [27] in a 42% yield (Scheme 1).…”

A new hydroxynaphthyl benzothiazole derived fluorescent probe for highly selective and sensitive Cu 2+ detection

“…Plotting the normalized fluorescence intensity against Log[Cu 2+ ] provides a nice linear relationship (Fig. 5), and the point of this line crossed the ordinate axis is regarded as the detection limit [58][59][60], which was found to be 1.34×10 -6 M. It was much lower than the limit of Cu 2+ concentration (20 μM) in drinking water permitted by the U.S.…”

Phenazine containing indeno-furan based colorimetric and “on–off” fluorescent sensor for the detection of Cu 2+ and Pb 2+

“…Detection limit was calculated from the titration data according to the reported method [35][36][37] by plotting a graph between normalized fluorescence intensity, (I max À I)/(I max À I min ) and log [M n þ ] at 481 nm (Fig. 12).…”