Excited state intramolecular proton transfer in amino 2-(2′-hydroxyphenyl)benzazole derivatives: Effects of the solvent and the amino group position

Rodembusch, Fabiano Severo; Leusin, Fernando Paulus; Campo, Leandra Franciscato; Stéfani, Valter

doi:10.1016/j.jlumin.2006.11.007

Cited by 128 publications

(108 citation statements)

References 41 publications

(25 reference statements)

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“…Similar behavior was observed in parent compounds. 31 In addition, as far as we know, these are the longer Stokes' shifts presented in the literature for a benzazolic compound in solution.…”

Section: Photophysical Characterizationmentioning

confidence: 77%

“…From these characteristics, it is possible to affirm that compound 8 can be largely found in the ground state as non-ESIPT conformers. 31 After the addition of fluoride, there is a decrease in the normal emission intensity, being related to a lower stabilization of these conformers in the presence of fluoride. In contrast, an increase in the intensity of the ESIPT emission is observed, indicating that the enol-cis conformer, responsible for the proton transfer in the excited state, is more stabilized in these conditions.…”

Section: Complexation Studymentioning

confidence: 98%

“…The benzothiazole derivative 9 presents an absorption maximum redshifted compared to the parent compound 8, as already observed in similar compounds, being explained by the better electron delocalization allowed by the sulfur atom compared to the oxygen atom. 31 In addition, a small solvatochromic effect was observed in both compounds, with redshifted absorptions in the more polar solvent DMSO than dimethylformamide (DMF). ).…”

Section: Photophysical Characterizationmentioning

confidence: 99%

“…23 Numerous applications can be found in chemistry, biology and biochemistry based on these ESIPT features. [24][25][26][27][28][29][30] The ESIPT process is characterized by a dual fluorescence emission tailored by the solvent polarity, 31 with the emission from the tautomeric form (T*) showing a large Stokes' shift (even in the solid state) compared to normal forms (N*). 32 This particular aspect of photophysics can present potential applications in the optical sensor field, as it drastically reduces the inner filter effect, improving the fluorescence analysis.…”

mentioning

confidence: 99%

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Synthesis and Photophysical Characterization of Proton Transfer-Based Thiourea Derivatives: Potential Application as Colorimetric Naked-Eye Chemosensor for Fluoride Detection in Solution

Silva¹,

Kroetz²,

Santos³

et al. 2017

J. Braz. Chem. Soc.

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Two new thiourea derivatives were synthesized through the reaction of photoactive aminohydroxybenzazoles and p-isothiocyanate benzoic acid via nucleophilic addition reaction. The compounds were characterized using high resolution mass spectrometry with eletrospray ionization (HRMS-ESI), Fourier transform infrared (FTIR), 13C and 1 H nuclear magnetic resonance (NMR) spectroscopies. UV-Vis and steady-state fluorescence in solution were also applied to characterize their photophysical behavior. The compounds present absorption in the ultraviolet region (ca. 300 nm) and fluorescence emission with a large Stokes' shift in the UV-A and green region, with the longer wavelength related to phototautomerism in the excited state (ESIPT). Both compounds were investigated as optical sensors for the detection of anions in solution, presenting a potential application for fluoride ion detection by naked-eye and UV-Vis spectroscopy. The continuous variation method plot gave a 1:1 stoichiometric ratio between the chemosensors and F -for the new formed species. The UV-Vis and 1 H NMR titration experiments reflect the establishment of a hydrogen bond interaction between the thiourea moiety of the chemosensors and fluoride. In addition, the presence of fluoride in solution tailored the fluorescence emission of one compound favoring the ESIPT emission.

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Section: Photophysical Characterizationmentioning

confidence: 77%

Section: Complexation Studymentioning

confidence: 98%

Section: Photophysical Characterizationmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Synthesis and Photophysical Characterization of Proton Transfer-Based Thiourea Derivatives: Potential Application as Colorimetric Naked-Eye Chemosensor for Fluoride Detection in Solution

Silva¹,

Kroetz²,

Santos³

et al. 2017

J. Braz. Chem. Soc.

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“…In contrast, benzazole heterocycle derivatives can display a large Stokes' shifted fluorescence [19] in the visible region (450-700 nm) coupled with high quantum yield (f) and molar extinction coefficient values. Such dyes are fluorescent owing to an excited state intramolecular proton transfer (ESIPT) mechanism, this fundamental process having received considerable attention since its discovery some 50 or so years ago [20].…”

Section: Introductionmentioning

confidence: 99%

Novel ESIPT fluorescent benzazolyl-4-quinolones: Synthesis, spectroscopic characterization and photophysical properties

et al. 2010

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Naked‐eye colorimetric and optical assay of heavy metals based on nano‐architectured prototype of organically functionalized mesoporous titania grafted with 4‐chloro‐2‐(4′‐methyl‐benzothiazol‐2′‐ylazo)‐phenol

El‐Nahass

Youssif

El‐Daly

et al. 2022

Applied Organom Chemis

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Heavy metals are extremely toxic, causing harm to aquatic and human life. Thus, this study focused on developing simple, colorimetric, and low-cost optical sensors for detection of metal ions with high selectivity and sensitivity. Here, a novel benzothiazole azo-dye, namely, 4-chloro-2-(4 0 -methyl-benzothiazol-2 0 -ylazo)-phenol (CMBTAP) was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), 1 H-nuclear magnetic resonance (NMR), 13 C-NMR, and mass spectroscopic techniques. This azo-dye has been anchored into the amino-functionalized mesoporous TiO 2 which synthesized using pluornic123 and cetyltrimethylammonium bromide as templates to yield CMBTAP-M-TiO 2 (1) and CMBTAP-M-TiO 2 (2), respectively. The designed nanosensors were characterized by FT-IR, transmission electron microscopy, nitrogen adsorption-desorption isotherms, X-ray diffraction, and thermogravimetric analyses. The colorimetric and optical sensing behavior of CMBTAP and its nanosensor analogs toward different metal ions like Ba 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cu 2+ , Cd 2+ , Hg 2+ , and Al 3+ were explored using naked-eye observations, steady-state absorption, and emission techniques. Significant changes in colors, the absorption and emission spectra were observed. The action of these nanosensors is reversible where on adding ethylenediaminetetraacetic acid to the formed complexes, the original absorption and emission spectra of the free sensors are restored, demonstrating that the chelation process is reversible. For CMBTAP and the nanosensors, the binding constants of the complexes formed with the used metal ions, and limit of detection (LOD) were calculated. In comparison with CMBTAP, the results revealed that the nanosensors exhibited a stronger binding affinity, selectivity, sensitivity, and lower LODs for the studied metal ions, implying that the sensing efficiency of CMBTAP is improved after loading onto the nanostructured TiO 2 . Thus, we have successfully converted the hazardous azo dye into an environmentally safe optical sensor for detection of toxic metal ions in wastewater with high sensitivity.

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Excited state intramolecular proton transfer in amino 2-(2′-hydroxyphenyl)benzazole derivatives: Effects of the solvent and the amino group position

Cited by 128 publications

References 41 publications

Synthesis and Photophysical Characterization of Proton Transfer-Based Thiourea Derivatives: Potential Application as Colorimetric Naked-Eye Chemosensor for Fluoride Detection in Solution

Synthesis and Photophysical Characterization of Proton Transfer-Based Thiourea Derivatives: Potential Application as Colorimetric Naked-Eye Chemosensor for Fluoride Detection in Solution

Novel ESIPT fluorescent benzazolyl-4-quinolones: Synthesis, spectroscopic characterization and photophysical properties

Naked‐eye colorimetric and optical assay of heavy metals based on nano‐architectured prototype of organically functionalized mesoporous titania grafted with 4‐chloro‐2‐(4′‐methyl‐benzothiazol‐2′‐ylazo)‐phenol

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