A fast-response, fluorescent ‘turn-on’ chemosensor for selective detection of Cr³⁺

Abstract

A fast-response, highly selective and sensitive chemosensor, 3, for Cr 3+ detection with turn-on fluorescence behavior in the physiological pH range was designed and synthesized. The chemosensor contained a combined push-pull system in which the fluorescent phenanthro[9,10-d]oxazole moiety acts as both the electron donor and a potential binding site. An electron deficient nitrile group served as the electron acceptor. A significant enhancement of fluorescene emission intensities was observed with increasing Cr 3+ concentration upon excition at 300 nm. The emission intensity reached its maximum on adding 8 equiv. of Cr 3+ where the quantum yield of 3-Cr 3+ was found to be 0.917, ca. 7-fold larger than the chemosensor 3.The selectivity mechanism of 3 for Cr 3+ was found to be based on the combined effects of the inhibition of ICT and CHEF. Remarkably the entire process was virtually complete in only 10 seconds, with a minimum detection limit for Cr 3+ of 1.72 × 10 -8 M -1 .

A Fluorescent Probe for Hydrogen Peroxide in Vivo Based on the Modulation of Intramolecular Charge Transfer

“…Usually, the excitation wavelength of phenanthroimidazole is shorter than 400 nm. 51,52 Benzonitrile as an electron-withdrawing group is linked with phenanthroimidazole (PAM) to quench the fluorescence because of the ICT process. We designed the probe with arylboronate, which acts as a recognition unit for H 2 O 2 .…”

“…Compound 2a was synthesized according to the reported procedure. 51 Dry paraformaldehyde (6.6 g) was added to a mixture of 4′hydroxybiphenyl-4-carbonitrile (3.1 g, 16 mmol), triethyl-amine (8.4 mL, 61 mmol), and anhydrous MgCl 2 (2.3 g, 24 mmol) in dry acetonitrile (50 mL). The mixture was heated to reflux for 6 h and then cooled to room temperature, acidified with 1 M HCl, and extracted with ethyl acetate (3 × 20 mL).…”

Modeling and Monte Carlo simulation on photothermal effect in Gd3Al3Ga2O12:Ce3+/Y3Al5O12:Cr3+ layered composite ceramic

“…If it hits Ce 3+ or Cr 3+ , the photon will be absorbed by the ion. Then according to the quantum yield of Ce 3+ and Cr 3+ , 23,24 ions will excite photons with a wavelength range of 500-750 nm. 8 (Simulating photon excitation of all wavelengths is not feasible, so we choose two emission peaks whose wavelengths are 558 and 700 nm.)…”

“…Therefore, it is a relatively convenient method to use the dynamic change of the weight to represent the new photons generated. The weight of each new photon is equal to the product of the original weight and the quantum yield (QY) 23,24 of the ion: $$\begin{equation}W \leftarrow W \cdot {\rm{QY}}\end{equation}$$…”

Highly selective and sensitive colorimetric chemosensor based on tricarboyanine for detection of Ag+ in industrial wastewater

“…Therefore, it is necessary to exploit new chemical sensors with a controllable manner and good regeneration ability. Lately, fluorescent chemosensors can achieve these advantages and also provide realtime detection of various heavy metal ions like Cu 2+ [25][26][27], Cd 2+ [28][29][30], Fe 3+ [31,32], Cr 3+ [33][34][35], Pb 2+ [36] and Zn 2+ [37][38][39]. On the basis of ion-induced change of fluorescence, fluorescent chemosensors have been widely developed owing to their simplicity and high detection limit [40].…”