A comprehensive spectroscopic, solvatochromic and photochemical analysis of 5-hydroxyquinoline and 8-hydroxyquinoline mono-azo dyes

Rashidnejad, Hamid; Ramezanitaghartapeh, Mohammad; Pesyan, Nader Noroozi; Mahon, Peter J.; Raposo, M. Manuela M.; Coelho, Paulo J.; Lup, Andrew Ng Kay; Soltani, Alireza

doi:10.1016/j.molstruc.2020.129323

Cited by 13 publications

(4 citation statements)

References 83 publications

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“…The second absorption maxima may be corresponding to a transition of electron density from the hydrazone NH group to the benzothiazole moiety (Scheme 3). These results, along with previously reported similar findings in ortho-hydroxyl azo dyes (Rashidnejad et al , 2021), intensively suggest that there may be an equilibrium between azo and hydrazone tautomers of the 5-chloro-7-hetarylazo-8-hydroxy quinoline Dyes 6 – 13 in solution state. The λ max of the dyes are presented in Table 1.…”

Section: Resultssupporting

confidence: 88%

Synthesis, characterization, spectroscopic properties and computational studies of some new azo dyes derived from 5-chloro-8-hydroxy quinoline

Mirsadeghi

Rufchahi

Zarrabi

2022

PRT

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Purpose The purpose of this study, 3-aminopyridine, 8-aminoquinoline and some new synthesized 2-aminobenzothiazoles were diazotized with nitrosyl sulfuric acid and subsequently coupled with 5-chloro-8-hydroxy quinoline to synthesize the corresponding heteroarylazo dyes 6–13. Design/methodology/approach The structures of dyes were characterized by mass, Fourier transform infra red, 1H proton nuclear magnetic resonance and ultra violet-visible spectroscopic techniques. Absorption spectra of the dyes were measured in acetic acid, ethanol, chloroform, acetonitrile, dimethyl formamide and dimethyl sulfoxide and correlated with the nature of the solvents and substituents. The effects of varying pH on the absorption wavelengths of the azo dyes were also studied. In addition, the acidity constants (pKa) of the dyes were determined using the spectrophotometric method in an ethanol-water mixture (80:20, v/v) at 20–23°C. Besides, density functional theory (DFT) calculations were carried out to compare the energies of proposed azo and hydrazone tautomers of the dyes. Findings The results showed that the withdrawing chloro groups on the diazo moiety have significant influence (red shift) on the electron absorption spectra of these dyes. In addition, introducing electron withdrawing chloro groups into the benzothiazoles moiety increased the acidic character of dyes. Originality/value The synthesized 7-hetroarylazo-5-chloro-8-hydroxy quinoline dyes are new members in the 8-hydroxyquinoline azo dyes family, where very few details regarding the synthesis of such dyes are reported before in the literature. They are unique in terms of synthesis, spectral properties and DFT calculations.

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Section: Resultssupporting

confidence: 88%

Synthesis, characterization, spectroscopic properties and computational studies of some new azo dyes derived from 5-chloro-8-hydroxy quinoline

Mirsadeghi

Rufchahi

Zarrabi

2022

PRT

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“…Generally, the azo form predominates in non-polar solvents, whereas the hydrazone form dominates in polar solvents. [32] Furthermore, one of the molecules (2) contains fluoro-substituent, which, due to electron-withdrawal can have a significant impact the electronic properties; thus, understanding the structural and electronic features of the above-mentioned synthesized compounds is a prerequisite. Compound 1 showed a UV-vis spectrum in benzene (non-polar solvent) (Figure 2), comprising two distinct absorption bands, one with a peak at 336 nm attributed to ππ* transitions and another one with a peak at 455 nm ascribed to n-π* transitions.…”

Section: Design and Synthesis Of Azo Switch Structural And Electronic...mentioning

confidence: 99%

Light Triggered Reversible Aggregation/Dispersion of Hydroxy Azo‐benzenes During Photo Switching: Solvent, Ions Assisted Dispersion, and Induced Quenching Emission

Patel,

Das,

Mishra

et al. 2024

ChemPhotoChem

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Hydroxy azo‐benzenes are very well known for their rapid trans ⇆ cis photoisomerization under polar solvents. In contrast, we synthesized two hydroxymethylated‐hydroxyazobenzene derivatives and investigated their light‐triggered photoisomerization and stability under polar solvents. The result showed just opposite behavior and very slow trans ⇆ cis isomerization was observed (minutes‐days). Thus, the UV‐vis spectrum revealed a very low decrease in the absorbance of p‐p* transition. Surprisingly, the isomerization process became faster with the addition of ionic species. Here, we attempted to understand the underlying cause of the unusual photo‐switching behavior. The presence of hydroxymethyl and fluorine substituents was found to have a significant effect on the stability of the trans and photo‐isomerized cis products. Here, it was confirmed with NMR and DLS studies that the unusual photostability of trans compounds was caused by polar solvent‐assisted aggregation (hydrodynamic radius, RH 5660‐1720 nm) which underwent dispersion (RH, 220‐68 nm) and formed a significant stable solvated photoproduct under photoirradiation. Furthermore, this aggregation‐dispersion was found to be very slowly reversible. Further, the fluorescence emission demonstrated a characteristic dispersion‐induced quenching. Regular photoswitching was observed under non‐polar conditions in benzene where an expected blue shift of p‐p* transition and an increase in the intensity of n‐p* transitions.

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“…Azo dyes are highly stable colored organic compounds within the visible part of the light spectrum, owing to their chromophore parts that contain one or more azo linkages (-N=N-) attached to two or more aromatic rings [ 1 ],[ 2 ]. They are considered to have excellent biochemical, absorption, nonlinear optic, and emission properties [ 3 ],[ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Combination of smartphone digital image colorimetry and UV-Vis spectrophotometry as detection systems with solidified floating organic drop microextraction as preconcentration method for the quantification of methyl red in wastewater samples

BOMBOM,

GİRGİN,

ZAMAN

et al. 2023

Turkish Journal of Chemistry

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In this study, a portable smartphone-based digital image colorimetric system (SDIC) was designed and integrated with a solidified floating organic drop microextraction method (SFODME) for the quantification of methyl red in textile wastewater samples. The RGB (red, green, and blue) data were evaluated for each captured image, and the green channel was selected for quantification due to its linear response for the analyte. Under optimal conditions, an acceptable linear range was recorded for the analyte. The proposed method recorded a limit of detection (LOD) value of 0.046 mg/L. The developed microextraction method was also combined with UV-Vis spectrophotometry, which recorded an LOD value of 0.012 mg/L. Real sample analysis was carried out with textile wastewater samples to check the applicability/accuracy of the developed method, using a matrix matching calibration strategy to enhance quantification accuracy. Satisfactory percent recoveries in the range of 93.3%–114.3% and 92%–92.7% were recorded for the SFODME-SDIC and SFODME-UV methods, respectively.

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A comprehensive spectroscopic, solvatochromic and photochemical analysis of 5-hydroxyquinoline and 8-hydroxyquinoline mono-azo dyes

Cited by 13 publications

References 83 publications

Synthesis, characterization, spectroscopic properties and computational studies of some new azo dyes derived from 5-chloro-8-hydroxy quinoline

Synthesis, characterization, spectroscopic properties and computational studies of some new azo dyes derived from 5-chloro-8-hydroxy quinoline

Light Triggered Reversible Aggregation/Dispersion of Hydroxy Azo‐benzenes During Photo Switching: Solvent, Ions Assisted Dispersion, and Induced Quenching Emission

Combination of smartphone digital image colorimetry and UV-Vis spectrophotometry as detection systems with solidified floating organic drop microextraction as preconcentration method for the quantification of methyl red in wastewater samples

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