Thio-Mayan-like Compounds: Excited State Characterization of Indigo Sulfur Derivatives in Solution and Incorporated in Palygorskite and Sepiolite Clays

Rondão, Raquel; Melo, J. Sérgio Seixas de

doi:10.1021/jp306209y

Cited by 23 publications

(21 citation statements)

References 64 publications

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“…An ozonefree 450 WX enon lamp was used as the excitation source, the emission detector was either aH amamatsu R928 Photomultiplier (200-900 nm range), cooled with aP roducts for Research thermoelectric refrigerated chamber (model PC177CE005), or aHamamatsu R5509-42 (900-1400 nm range), cooled to 193 Ki naliquid nitrogen chamber (Products for Research model PC176TSCE-005), and ap hotodiode was used as the reference detector. [10,55] Fluorescence decays were measured using home-built nanosecond [56] and picosecond [57] time correlated single photon counting (TCSPC) equipments described elsewhere. [58] Different excitation sources were used.…”

Section: Methodsmentioning

confidence: 99%

“…To un-derstandt he precise nature of the indigo-palygorskite interaction and its relationt ot he stability and shade of the pigment, exhaustive studies of both archaeological and synthetic MB samples have been performed. Several new indigo-based hybridm aterials have been prepared, such as indigo-sepiolite, [9][10][11] indigo-silicalite [11,12] and indigo-laponite, [13] as well as hybrids fromi ndigo derivatives such as thioindigo [10] and indigocarmine (indigo-5,5'-disulfonic acid disodium salt). [14,15] Like indigo, indigo carmine is ab lue dye extensively used in the textile industry,s pecifically in the blue jeans industry.H ybrids containing this dye have been prepared by its intercalation in layeredd ouble hydroxides (LDHs).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Indigo Carmine‐Based Hybrid Nanocomposite with Supramolecular Control of Dye Aggregation and Photobehavior

Costa

Gomes

Pillinger

et al. 2015

Chemistry A European J

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Zn-Al layered double hydroxides (LDHs) containing solely indigo carmine (IC) or 1-hexanesulfonate (HS) anions, or a mixture of the two with different HS/IC molar ratios, were prepared by the direct synthesis method and characterized by various techniques. Hydrotalcite-type phases were obtained with basal spacings of 17.6 Å for the LDH intercalated by IC (IC-LDH) and 18.2-18.3 Å for the other materials containing HS. From the basal spacing for IC-LDH and UV/Vis spectroscopic data, it is proposed that the dye molecules assemble within the interlayer galleries to form a J-type stacking arrangement. A comprehensive electronic spectral and photophysical study was undertaken for IC in solution and all materials, aiming to obtain a detailed characterization of the host-guest and guest-guest interactions. In solution (the solvent surrounded "isolated" molecule), IC presents a fast excited state proton transfer with rate constants of ∼1.2-1.4×10(11) s(-1) , which is linked to the very efficient radiationless deactivation channel. In the solid state it is shown that incorporation of IC within the LDH decreases the level of aggregation, and that further addition of HS induces the appearance of isolated IC units within the LDH galleries. The indigo carmine-based nanocomposites reported constitute a step forward in the design of hybrid materials with tunable properties.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Indigo Carmine‐Based Hybrid Nanocomposite with Supramolecular Control of Dye Aggregation and Photobehavior

Costa

Gomes

Pillinger

et al. 2015

Chemistry A European J

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“…In solution, it can be present in three forms: the (neutral) keto, , the (reduced) leuco, − and the (oxidized) dehydroindigo (DHI) species, each of them presenting very different spectral and excited-state characteristics. However, in contrast with what happens with keto indigo, with the leuco and DHI species, (photo)isomerization can occur. , Indigo is also one of the key constituents of the first organic–inorganic hybrid, Maya Blue, in which the clay palygorskite imparts an additional stability to the dye. − The correct structure (including the interaction of the molecule with the inorganic host) is still a theme of debate. − In recent years, particular attention has been directed toward understanding the mechanisms behind the decay of excited indigo, and parent molecules such as indigocarmine. It was shown both experimentally and theoretically that the high stability of indigo is linked to an excited-state proton transfer (ESPT) process, ,,− although previous reports, based on studies with a tetramethyl indigo derivative, suggested the absence of ESPT in indigo.…”

Section: Introductionmentioning

confidence: 99%

Excited-State Proton Transfer in Indigo

et al. 2017

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Excited-state proton transfer (ESPT) in Indigo and its monohexyl-substituted derivative (Ind and NHxInd, respectively) in solution was investigated experimentally as a function of solvent viscosity, polarity, and temperature, and theoretically by time-dependent density functional theory (TDDFT) calculations. Although a single emission band is observed, the fluorescence decays (collected at different wavelengths along the emission band using time-correlated single photon counting (TCSPC)) are biexponential, with two identical decay times but different pre-exponential factors, which is consistent with the existence of excited-state keto and enol species. The femtosecond (fs)-transient absorption data show that two similar decay components are present, in addition to a shorter (<3 ps) component associated with vibrational relaxation. From TDDFT calculations it was shown that with both Ind and NHxInd, the reaction proceeds through a single ESPT mechanism driven by an Arrhenius-type activation through a saddle point, which is enhanced by tunneling through the barrier. From the temperature dependence of the steady-state and time-resolved fluorescence data, the activation energy for the process was found to be ∼11 kJ mol for Ind and ∼5 kJ mol for NHxInd, in close agreement with the values calculated by TDDFT: 12.3 kJ mol (Ind) and 3.1 kJ mol (NHxInd). From time-resolved data, the rate constants for the ESPT process in dimethyl sulfoxide were found to be 9.24 × 10 s (Ind) and 7.12 × 10 s (NHxInd). The proximity between the two values suggests that the proton transfer mechanism in indigo is very similar to that found in NHxInd, where a single proton is involved. In addition, with NHxInd, the TDDFT calculations, together with the viscosity dependence of the fast component, and differences in the activation energy values between the steady-state and time-resolved data indicate that an additional nonradiative process is involved, which competes with ESPT. This is attributed to rotation about the central carbon-carbon bond, which brings the system close to a conical intersection (CI). The CI is of the sloped type, where the seam is reached through an OH stretching vibration.

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“…'Maya Powder' hybrid pigments were prepared by compounding palygorskite with thioindigo and Ciba Brilliant Pink, respectively. The results showed that the mixture of palygorskite and two indigo sulfur derivatives displayed remarkable stability toward organic solvents, acids, and alkalis [15]. For sepiolite/basic red 46 hybrid pigments, the sepiolite was believed to protect the basic red 46 molecules from the attack of acid, base, heat and ultraviolet light [16].…”

Section: Introductionmentioning

confidence: 99%

Study on the effects of cationic dyes species on the structure and performance of sepiolite hybrid pigments

Song

Zhai

Zhang

et al. 2022

Mater. Res. Express

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In this work, sepiolite hybrid pigments were prepared with four kinds of cationic dyes with different structures and functional groups, Basic orange 2 (BO2), Mytheme blue (MB), Basic red 18 (BR18) and Basic red 2 (BR2), by the vacuum method. The obtained samples were respectively named as BO2/Sep, MB/Sep, BR18/Sep and BR2/Sep. The sepiolite hybrid pigments were characterized and tested by XRD, FT-IR, Microporous physical/chemical adsorption analyzer, thermal analyzer, et al. The effects of cationic dyes structure and functional groups types on the positions and loading capacity of cationic dyes in sepiolite hybrid pigments were investigated. The results indicated that positions and loading capacity of cationic dyes in sepiolite hybrid pigments are not only related to the size of the cationic dyes but also related to the functional groups and electrical properties of the cationic dyes. The smaller the size of the cationic dyes, the greater the positive charge, and the stronger the functional groups interact with the sepiolite, the greater the amount that enters the sepiolite channel and is adsorbed. The loading capacity of cationic dyes in hybrid pigments dropped as the order MB/Sep, BO2/Sep, BR18/Sep, BR2/Sep. In addition, the position and interaction of cationic dye in sepiolite determine the stability of hybrid pigments. The resistance of hybrid pigments to the acid decreased as the order MB/Sep, BR18/Sep, BO2/Sep, BR2/Sep. In the base medium, the order is MB/Sep, BO2/Sep, BR18/Sep, BR2/Sep. The weatherability of the hybrid pigments was also better than pure cationic dyes.

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Thio-Mayan-like Compounds: Excited State Characterization of Indigo Sulfur Derivatives in Solution and Incorporated in Palygorskite and Sepiolite Clays

Cited by 23 publications

References 64 publications

An Indigo Carmine‐Based Hybrid Nanocomposite with Supramolecular Control of Dye Aggregation and Photobehavior

An Indigo Carmine‐Based Hybrid Nanocomposite with Supramolecular Control of Dye Aggregation and Photobehavior

Excited-State Proton Transfer in Indigo

Study on the effects of cationic dyes species on the structure and performance of sepiolite hybrid pigments

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