A Novel Selective “Turn‐On” Fluorescent Chemosensor Based on Thiophene Appended Cyclotriphosphazene Schiff Base for Detection of Ag⁺ Ions

Abstract

The salicylaldehyde-functionalized cyclotriphosphazene (1) and thiophene appended cyclotriphosphazene based Schiff base (2) were designed and synthesized. The characterizations were carried out via MALDI-TOF, FTIR, 13 C, 31 P and 1 H NMR. The photophysical behavior of compound 2 was evaluated by UV-Vis absorption, time-resolved fluorescence, excitation-emission matrix (EEM) analysis, steady-state fluorescence, and 3Dfluorescence spectroscopies. Compound 2 demonstrated selective fluorescence "turn-on" response at 427 nm towards to Ag + ion when the tested competitive species did not affect fluorescence signal. The binding and sensing mechanisms were evaluated by DFT calculations which approved that the PET process between C=N and fluorophore groups was inhibited, and the fluorescence "turn-on" response was obtained with the contribution of CHEF after 1 : 1 coordination of compound 2 with Ag + ion. The LOD and LOQ were calculated as 3.15 and 9.45 μmol L À 1 , respectively in the linear range of 9.35-210.00 μmol L À 1 Ag + ions. The practical application of compound 2 for Ag + determination was successfully performed in environmental waters after optimization of measurement conditions. The obtained results approved that compound 2 is a selective fluorescent sensor for Ag + ions and it can be used for spectrofluorimetric Ag + determination in real samples. Importantly, according to the literature, this report is the first example of cyclotriphosphazene based fluorescent sensor for Ag + ion.

Chiral Ionic Covalent Organic Framework as an Enantioselective Fluorescent Sensor for Phenylalaninol Determination

“…The fluorescence decay curves of L -TB-COF before and after adding R -PAL are recorded in Figure S16. The almost unchanged fluorescence lifetimes demonstrated the formation of static host–guest complexes. , Moreover, the chiral discrimination ability of L -TB-COF to PAL was further proven by Raman spectra in Figure S17. Apparent Raman scattering intensity enhancement was observed in the R -PAL + L -TB-COF system, while the Raman scattering intensity of the S -PAL + L -TB-COF system was almost the same as that of the blank L -TB-COF.…”

Small‐Molecule Fluorescent Probe: Ratiometric and Selective Detection of Sodium Ions for Imaging and Solid‐State Sensing Applications

“…Where, σ is the standard deviation of blank measurement, [112] and k is the slope between fluorescence intensity versus respective metal ion concentration.…”

Design, synthesis, crystal structure, photophysical behavior and aggregation-induced emission of a novel pyrene scaffold multifunctional Schiff base ligand: inhibition of digestive enzymes and docking studies

“…Therefore, the design and development of this type of organic molecules is significant for the generation of efficient blue emissive materials. 6 The design and syntheses of new molecules with aggregation-induced-emission properties has kindled contemporary keen and unabated interest. 7 These probes with an AIE feature actively manifest very weak emission in solution.…”