Benzothiazole azo derivatives as colorimetric probes for optical recognition of different metal ions and anions

Abstract

In this study, we report on novel optical chemosensors containing benzothiazole moeity, namely, 2‐(6‐chloro‐benzothiazol‐2‐yl azo)‐4‐methyl‐phenol (CBAMP) and 1‐(6‐chloro‐benzothiazol‐2‐yl azo)‐naphthalen‐2‐ol (CBAN), which were synthesized and characterized by Fourier transform infrared spectroscopy (FT‐IR), 1H‐NMR, 13C‐NMR, and mass spectrometry. The solvatochromic behavior was explored in different solvents of various polarities to explore the active fluorescent tautomer, and the photophysical parameters have been measured. The naked eyes, as well as ultraviolet–visible (UV–Vis) and fluorescence spectroscopy, were used to study the colorimetric and optical sensing properties of CBAMP and CBAN toward various metal ions and anions. These chemosensors have a strong detecting ability, with excellent sensitivity and selectivity for certain of the metal ions investigated, as well as CO32− and CN− over other anions. The Benesi–Hildebrand and Job's plots were used to determine the binding constants and stoichiometry of the formed metal ions–sensor complexes, respectively. Co2+ and Cu2+ ions have lower detection limits in CBAMP and CBAN than other metal ions (6.4 × 10−7 and 8.4 × 10−7 M, respectively). Furthermore, fluorescent imaging investigations for Co2+ and Cu2+ ions in living cells reveal CBAMP and CBAN's promise for biological chemosensing.

Tunable Anticorrosive Effects of Newly Synthesized Benzothiazole Azo Dyes by Potassium Iodide Synergism for Carbon Steel in 1 M HCl: Combined Experimental and Theoretical Studies

“…The molecular structure of the investigated dyes, CMBTAP, CBAN, and CBAMP, was confirmed by FT-IR, 1 H NMR, 13 C NMR, and mass spectroscopy. Both CBAN and CBAMP dyes have been characterized and discussed by us previously . The FT-IR spectrum of CMBTAP showed sharp bands at vibrational frequencies (cm –1 ): 1469 (C–S), 1597 (C–N), 1532 (CN), 1534 (NN), 3120 (ArCH), 2930 (aliphatic–CH 3 group), 760 (C–Cl), and a sharp band is observed at 3456 cm –1 corresponding to stretching vibrations of the −OH group; see Figure S1.…”

“…Benzothiazole Azo Dyes. The investigated azo dyes, 4chloro-2-(4-methyl-benzothiazol-2-ylazo)-phenol (CMBTAP) 1-(6-chloro-benzothiazol-2-ylazo)-naphthalen-2-ol (CBAN), and 2-(6-chloro-benzothiazol-2-ylazo)-4-methyl-phenol (CBAMP) (Scheme 1), were synthesized following the procedures previously described by us 20 to yield brownish red, reddish brown, and orange solids of CMBTAP, CBAN, and CBAMP, respectively, which were dried and recrystallized from ethanol.…”

Facile Synthesis of Highly Sensitive Hybrid Nanomaterial Modified with a Fluorescent Probe for Detection of Fe3+ Ions

“…The fluorometric approach was used to calculate the LOD of the nanosensor. The nanosensor's LOD values for Mn 2 + , Fe 3 + , Zn 2 + , Ag + , Cd 2 + , Hg 2 + , Al 3 + , and Pb 2 + ions were measured in H 2 O using the equation; [31] LOD = 3S/b; where S is the deviation and b is the slope of the calibration curve line. The emission spectra of eight aqueous solutions were evaluated in this trial, and LOD values were obtained and summarized in Table 2, revealing that the Fe 3 + ion has a very low detection concentration of 5.6×10 À 5 M when compared to other metal ions.…”

Azoheteroarene and Diazocine Molecular Photoswitches: Self‐Assembly, Responsive Materials and Photopharmacology

“…[20][21] The conversion of Z-isomer to E-isomer for DZ is attained via 370-400 nm light (blue) irradiation with over 90 % efficiency while the half lifetime of thermal relaxation is usually a few hours. We note that there are several other azoheteroarene photoswitches available, [5,[9][10][11][12][13][14][15] including arylazoimidazoles, [22] arylazoindazoles, [23] arylazaindoles, [24] arylazothiophenes, [25] arylazotriazoles, [26] azopyrimidines, [27] azobenzothiazoles, [28] azopyroles [29] etc., which are yet to be explored extensively in the context of material or biology related applications and will not be considered here.…”