Tautomeric photoswitches: anion-assisted azo/azine-to-hydrazone photochromism

Filo, Juraj; Tisovský, Pavol; Csicsai, Klaudia; Donovalová, Jana; Gáplovský, Martin; Gáplovský, Anton; Cigáň, Marek

doi:10.1039/c9ra02906k

Cited by 9 publications

(8 citation statements)

References 37 publications

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“…At the same time, the intensity of absorption around 400 nm decreases. The same changes with the change in concentration were observed in the case of isatin naphthylimide hydrazones [11] and isatin 4-nitrophenyl-hydrazone [12].…”

Section: Introductionsupporting

confidence: 69%

Effect of a =X-NH-Fragment, (X = C, N), on Z/E Isomerization and ON/OFF Functionality of Isatin Arylhydrazones, ((Arylamino)Methylene)Indolin-2-Ones and Their Anions

et al. 2020

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The subject of this work was the study of thermally and photochemically stimulated Z ↔ E isomerization and hydrazo ↔ azo tautomerism of Z- and E-isomers of isatin arylhydrazones and ((arylamino)methylene)indolin-2-ones and their anions. Using NMR, UV-Vis spectroscopy, kinetic measurements, and HPLC, we studied the relationship of structure, (Z- and E-isomers), of these compounds and hydrazo=azo tautomerism. The ON/OFF functionality of these compounds and their anions using light to stimulate switching between ON and OFF states was investigated. We pointed out the characterization of the effect of =N- and =CH- structural fragments and aryl structure on ON and OFF states of isatin arylhydrazones and ((arylamino)methylene)indolin-2-ones.

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Section: Introductionsupporting

confidence: 69%

Effect of a =X-NH-Fragment, (X = C, N), on Z/E Isomerization and ON/OFF Functionality of Isatin Arylhydrazones, ((Arylamino)Methylene)Indolin-2-Ones and Their Anions

et al. 2020

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“…One of the resonating structures is due to the azo-anionic form formed due to single-step deprotonation reaction, whereas the other is due to the hydrazone-anion form under strong alkaline conditions. [37,38] The compounds possessing imine nitrogen atom (> C=N) generally have a less negative reduction potential compared to the aromatic skeleton. Under alkaline conditions, the deprotonation reaction will tend to increase the electron density on the naphthalene ring of HDBS, which induces intramolecular charge transfer to occur from the naphthalene ring towards the benzene ring linked to the sulphonamide group forming a D (donor)-π-A (acceptor) system.…”

Section: Decoding the Halochromism Of Hdbsmentioning

confidence: 99%

Unraveling Halochromism of Azo‐Based Sulphonamide and Its Real‐World Applications: A Combined Experimental and Theoretical Approach

Joshi,

Ganorkar

et al. 2023

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Halochromic azo dyes have versatile applications, including sensing and anti‐counterfeiting, due to their reversible color‐changing properties. In this work we investigated the structure‐dependent halochromism of azo compound (E)‐4‐((2‐hydroxynaphthalen‐1‐yl)diazenyl)benzenesulfonamide (HDBS) and explore its potential applications using experimental and theoretical approaches. Different spectroscopic techniques confirm the structural change in the dye as a consequence of tautomerism reaction upon changing pH (7 to 13). The stable form of hydrazone is isolated and characterized. Based on the spectroscopic characterization, it is concluded that the azo form exists at pH ≤ 9, whereas the hydrazone form at highly alkaline pH. To understand the origin of the absorption peaks, the stability, and tautomerism in water, DFT and TD‐DFT calculations are performed. A reasonable agreement between the theoretical and experimental observations enabled us to unravel the structure‐dependent halochromism. Further, we have shown that HDBS‐coated paper can be a real‐time visual sensor to monitor fish freshness and for anti‐counterfeiting ink. It changes colors with pH shifts, alerts consumers about the status of food. Additionally, erasable paper strip reduces paper waste and chemical pollution. The findings presented in this work provide a promising avenue for the development of halochromic azo compounds with potential applications in sensing and anti‐counterfeiting.

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“…Významná změna barvy po ozáření UV světlem byla nejprve prozkoumána optickou spektroskopií (difuzní reflektancí), která naznačovala vznik cis izomeru. V některých případech však přicházel v úvahu i světlem indukovaný přenos protonu (azo/hydrazo formy), 40 který probíhá na azoskupině. Přirozené zastoupení izotopu 15 N je však nízké (0,37 %), a proto bylo nutné připravit deriváty značené izotopem 15 N na azoskupině.…”

Section: Polymorfní Přeměna Indukovaná Enkapsulací Do Glykopolymerníc...unclassified

Advanced NMR Spectroscopy Methods for Study of Structure and Properties of Small Molecules

Procházková

2022

Chem. Listy

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NMR spectroscopy is the key analytical method for determination of chemical structure and investigation of physico-chemical properties, such as non-covalent interactions, tautomeric equilibria or polymorphism. In this work, selected examples of using advanced NMR methods in structural analysis are discussed. (1) NMR spectroscopy with in situ irradiation useful to monitor photochemical processes, (2) 31P NMR spectroscopy for reaction monitoring and probing stereochemistry and (3) solid-state NMR spectroscopy to investigate polymorphism.

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Tautomeric photoswitches: anion-assisted azo/azine-to-hydrazone photochromism

Abstract: The photoswitching behaviour of isatin 4-nitrophenylhydrazones in presence of anions was investigated.

Cited by 9 publications

References 37 publications

Effect of a =X-NH-Fragment, (X = C, N), on Z/E Isomerization and ON/OFF Functionality of Isatin Arylhydrazones, ((Arylamino)Methylene)Indolin-2-Ones and Their Anions

Effect of a =X-NH-Fragment, (X = C, N), on Z/E Isomerization and ON/OFF Functionality of Isatin Arylhydrazones, ((Arylamino)Methylene)Indolin-2-Ones and Their Anions

Unraveling Halochromism of Azo‐Based Sulphonamide and Its Real‐World Applications: A Combined Experimental and Theoretical Approach

Advanced NMR Spectroscopy Methods for Study of Structure and Properties of Small Molecules

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