Photophysical and Spectroscopic Studies of Indigo Derivatives in Their Keto and Leuco Forms

Melo, J. Sérgio Seixas de; Moura, A. P.; Melo, M. J.

doi:10.1021/jp040753y

Cited by 18 publications

(20 citation statements)

References 15 publications

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“…The solution was left to bubble for 20 min and sealed in a device (which keeps the solution in inert atmosphere) as described elsewhere. [30] Absorption and fluorescence spectra were recorded on Shimadzu UV-2100 and Horiba-Jovin-Yvon Spex Fluorog 3-2.2. spectrophotometers, respectively. Fluorescence spectra were corrected for the wavelength response of the system.…”

Section: Methodsmentioning

confidence: 99%

Characterization of the Excited States of Indigo Derivatives in their Reduced Forms

2010

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A comprehensive characterization of the electronic spectral and photophysical properties of the leuco (reduced) form of several indigo derivatives, including indigo and Tyrian Purple, with di-, tetra-, and hexa-substitution, was obtained in solution. The characterization involves absorption, fluorescence, and triplet-triplet absorption spectra, together with quantitative measurements of quantum yields of fluorescence, phi(F) (0.46-0.04), intersystem crossing, phi(Tau) (0.013-0.034), internal conversion, phi(IC), and the corresponding lifetimes. The position and degree of substitution promote differences in the spectral and photophysical properties displayed by the investigated leuco derivatives. The phi(F) values are about two orders of magnitude higher than those previously obtained for the corresponding keto forms. Also in contrast with the behavior found for the keto forms, the S(1) approximately approximately -->T(1) intersystem crossing is an efficient route for the excited-state deactivation channel. These findings strengthen the fact that, in contrast to keto indigo where the internal conversion dominates the deactivation of the excited-state, with leuco indigo (and derivatives), the excited state deactivation involves competition between internal conversion, triplet state formation, and fluorescence. A time-resolved investigation of one of the compounds in glycerol showed the presence of a photoisomerization process.

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Section: Methodsmentioning

confidence: 99%

Characterization of the Excited States of Indigo Derivatives in their Reduced Forms

2010

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“…enables one to estimate the third-order nonlinear susceptibility χ (3) in the limit of very long wavelengths (i.e., at hν → 0 when the refractive index is equal to n o ). In Eq.…”

Section: Resultsmentioning

confidence: 99%

“…The remarkable stability of indigo and its ring-substituted derivatives has been attributed to intramolecular hydrogen bonding between the two adjacent carbonyl and N-H groups. This keeps the molecule in a planar trans configuration, preventing a photochemical cis-to-trans isomerization [3]. It is well known that photochromic materials have great potentials for sensor and indicator devices [4].…”

Section: Introductionmentioning

confidence: 99%

Structural and optical characterizations of thin organic films of thioindigo

Khusayfan¹,

El-Nahass²

2016

Ukr. J. Phys. Opt.

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Abstract. We report on the structural and optical properties of the nanorods available in thermally evaporated thin films of thioindigo (TI). The structural features are investigated using X-ray diffraction, transmission electron microscopy and Fourier-transform infrared spectroscopy techniques. The optical constants of asdeposited thin TI films are determined in the wavelength region 200-2500 nm, using spectrophotometric measurements for the nearly normal light incidence. The type of optical transitions for the TI films is ascertained from the dispersion of their absorption coefficient. The real part of the refractive index in the region of optical transparency is analyzed basing on single-oscillator and Drude models. The thirdorder nonlinear susceptibility is obtained from the single-oscillator model and the Miller's rule.

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“…También se han encontrado trabajos sobre identificación de colorantes empleados como capas pictóricas [6,7] o como tintes para textiles. La mayoría de ellos se centraban en la identificación y caracterización de materiales [8].…”

Section: Introductionunclassified

Identification of colorant materials after an artificially aged process

López-Montes¹,

Dupont²,

Burgos³

et al. 2016

Opt. Pura Apl.

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ABSTRACT:Chemical composition and physical characteristics of art materials (support, paint layer, protection layer…) depend on different factors such as their origin, the application process, the storage conditions throughout the centuries and the ageing processes. The identification of aged organic dyes can be difficult due to the possible changes that their physical and chemical characteristics could have undergone with time. A comparative study between standard samples and samples aged in a controlled climate chamber under drastic conditions of humidity, temperature and light was carried out. The techniques of identification and evaluation used were High Performance Liquid Chromatography (HPLC) and UV-visible spectroscopy. Results showed that the cellulosic fibers confer greater resistance to dyes in all cases.Key words: Colour in art, identification, natural dyes, artificial aged process, conservation. RESUMEN:La composición química y las características físicas de los materiales artísticos (soporte, capa pictórica, capa de protección…) dependen de diferentes factores tales como la fuente de origen, el procedimiento utilizado para su aplicación, las condiciones de almacenamiento a través del tiempo y el proceso de envejecimiento. Se destaca, en este punto, la problemática de la identificación de los colorantes orgánicos después de su envejecimiento, ya que, en muchos casos, pueden haberse modificado sus características físicas o químicas. Para la identificación de los colorantes bajo estas condiciones se realizó un estudio comparativo entre las muestras patrón sin envejecer y las muestras artificialmente envejecidas en una cámara climática, sometiéndolas a condiciones drásticas de humedad, temperatura e iluminación. Las técnicas que se emplearon para identificar y evaluar los cambios sufridos por estos colorantes fueron la cromatografía líquida de alta resolución (HPLC) y la espectroscopía UV-visible. Los resultados demostraron que las fibras celulósicas confieren mayor resistencia a los colorantes en todos los casos.Palabras clave: Color en arte, identificación, colorantes naturales, proceso de envejecimiento artificial, conservación.

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Photophysical and Spectroscopic Studies of Indigo Derivatives in Their Keto and Leuco Forms

Cited by 18 publications

References 15 publications

Characterization of the Excited States of Indigo Derivatives in their Reduced Forms

Characterization of the Excited States of Indigo Derivatives in their Reduced Forms

Structural and optical characterizations of thin organic films of thioindigo

Identification of colorant materials after an artificially aged process

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