Picosecond spectroscopy of trans-thioindigo

Krysanov, S.A.; Алфимов, М. В.

doi:10.1016/0009-2614(80)87007-2

Cited by 15 publications

(6 citation statements)

References 12 publications

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“…These transient absorptions are similar to the S n ' S 1 absorption of thioindigo which peaks at B470 nm and B600 nm. 21,46,47 Because no bleaching can be seen around 640 nm where the S 1 ' S 0 and S n ' S 0 absorption overlap in DMF, extinction coefficient of the S n ' S 1 transition was concluded to be larger than that of the S 1 ' S 0 transition. The shoulder appearing around 605 nm in the DMF spectrum can be caused by the bleaching of the S 1 ' S 0 absorption with its maximum at 618 nm.…”

Section: Transient-state Absorption Spectramentioning

confidence: 99%

The effect of hydrogen-bonding on the ultrafast electronic deactivation dynamics of indigo carmine

Nagasawa

Taguri

Matsuda

et al. 2004

Phys. Chem. Chem. Phys.

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Section: Transient-state Absorption Spectramentioning

confidence: 99%

The effect of hydrogen-bonding on the ultrafast electronic deactivation dynamics of indigo carmine

Nagasawa

Taguri

Matsuda

et al. 2004

Phys. Chem. Chem. Phys.

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“…10,11 Regarding the previous time-resolved studies of indigo, the most common technique used has been time-resolved fluorescence. 12 Indigo derivatives, such as thioindigo, 13 indigo carmine, 14 dehydroindigo, 15 and leucoindigo, 16 have been studied by ultrafast techniques in an attempt to explain the high photostability of indigo, 17 a still controversial issue that can involve excited state intramolecular proton transfer (ESIPT). 17 Thus, time-resolved infrared (TRIR) and transient absorption (TA) spectroscopy studies can help to clarify this controversy.…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Spectroscopy of Indigo and of a Maya Blue Simulant

et al. 2016

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Maya Blue is a puzzling pigment found in objects produced by the ancient Maya civilization. It is a combination of indigo and palygorskite, and it is well-known for the high chemical and photochemical stability of the dye promoted by the clay confined environment. This pigment has survived over 1500 years, and it was first thought to be purely inorganic. The reasons for such stability have been investigated over the past years, and it may involve hydrogen bonds, complexation, and oxidation to dehydroindigo. However, these theories are not completely understood, and more evidence about indigo/palygorskite interactions must be obtained. In this study indigo and a Maya Blue simulant pigment were, for the first time, studied by transient absorption (TA) and time-resolved infrared (TRIR) spectroscopy. From such analysis it was possible to investigate the electronic excited states of indigo and the photochemistry behavior of the dye when interacting with the palygorskite. Concerning the TRIR measurements, the shifts of the C O and N−H vibrations indicate that hydrogen bonds are formed involving the dye and the coordinated water molecules present in the clay. Furthermore, a red shift is observed in the absorption of electronic ground state (50 nm) and also in the electronic excited state (27 nm) of Maya Blue simulant, suggesting that the excited states are stabilized by the clay. Indigo in DMSO solution presents a lifetime of ca. 120 ps while in the clay it becomes much shorter, ca. 3 ps. The shorter lifetime and also the red shift observed in the TA results suggest a stabilization of the first electronic excited state, which promotes a more efficient energy relaxation through conical intersection and, as a consequence, a faster excited state decay. Such factors can be important for the Maya Blue photostability, as they are also believed to be responsible for the high photostability of DNA and melanin.

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“…The apparatus used to measure picosecond transient absorbance spectra was the same as that described in detail elsewhere. 9 Briefly, it includes a mode-locked Nd:phosphate glass laser on the basis of an unstable resonator configuration and amplifier system to produce single 6 ps, TEMo0 pulses at 1055 nm. The second 528 nm (an energy 1 mJ) and third 352 nm (an energy 0.5 mJ) harmonics were used as excitation pulses.…”

Section: Methodsmentioning

confidence: 99%

“…The existence of two characteristic times of the isomer X decay allows us to choose the following kinetic scheme from the many one proposed for the photochromic processes analysis 9…”

mentioning

confidence: 99%

Picosecond Flash Photolysis of Photochromic Spiropyrans

Krysanov

Алфимов

1984

Laser Chemistry

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The transient species involved in photocoloration and photobleaching of indoline 6-nitrosubstituted spiropyran solutions at room temperature were studied by picosecond flash photolysis. Transient absorption spectrum of spiropyran colorless form consists of two bands peaked at 440 and 585 nm and is assigned to the photoinduced intermediate non-planar cis configuration with the breaked C—O bond of the pyran ring. This transient is found to have the buildup time shorter than 10 ps and initial decay times of about 10 ns in benzene and 5 ns in ethanol. The colored form exhibits the transient absorption peaked at 460 nm with the lifetime of about 200 ps in ethanol which is assigned to Sn ← S1 absorption of colored form. The predominant decay channel of the colored form S1 state is shown to be internal conversion S1 ⇝ S0 with the quantum yield of about 0.70 ± 0.15.

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Picosecond spectroscopy of trans-thioindigo

Cited by 15 publications

References 12 publications

The effect of hydrogen-bonding on the ultrafast electronic deactivation dynamics of indigo carmine

The effect of hydrogen-bonding on the ultrafast electronic deactivation dynamics of indigo carmine

Time-Resolved Spectroscopy of Indigo and of a Maya Blue Simulant

Picosecond Flash Photolysis of Photochromic Spiropyrans

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