Ultrafast formation of transients in spiropyran photochromism

Krysanov, S.A.; Алфимов, М. В.

doi:10.1016/0009-2614(82)87037-1

Cited by 105 publications

(71 citation statements)

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“…In accordance with the conclusions drawn by Krysanov and Alfimov [31] from their picosecond experiments on nitro-BIPS, we assume that the lifetime of the initially excited state of the spiro form is below the time resolution of our pump-probe experiment (< 2 ps). This is to say, the unresolved rise time of the absorbance around 600 nm induced by the UV pulse represents the inverse of the sum of the decay rate &(S**,X*) of the higher excited state S** into an excited state of the intermediate, X*, and the rate for vibronic relaxation, fc"(S**), within the singlet manifold of the spiro form (competition between photochemical reaction and vibronic relaxation has been proposed by Becker et al [42] to explain the excitation wavelength dependence of the reaction yield).…”

Section: Discussionsupporting

confidence: 73%

“…Investigations of 6-nitrosubstituted indolinospiropyrans (nitro-BIPS) led to the conclusion [31,40,41] that the precursor in the formation of X is a triplet state. Furthermore, it was speculated that this isomer X should also appear as intermediate in photo-bleaching of some merocyanine forms [2].…”

Section: Discussionmentioning

confidence: 99%

“…state of X. We will, therefore, neglect the triplet route in our discussion of the results described above.Furthermore, one can state that aggregation was also discussed only in connection with nitro-substituted derivatives[7,31,43,44], and was claimed to be of no importance in case of other indolinospiropyrans[22]. This may be taken as evidence that intersystem crossing, leading to the triplet state of either the spiro form or the cisoid intermediate, must only be taken into consideration when dealing with nitro-substituted derivatives.…”

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confidence: 99%

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Investigation of the Photochromic Effect of Spiro [indolino-naphthoxazine] Derivatives by Time-Resolved Spectroscopy

Schneider¹

1987

Zeitschrift Für Physikalische Chemie

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Based on the results of different spectroscopic techniques, a reaction scheme is proposed to explain the photochromism of indolinospironaphthoxazine derivatives. Pump-probe experiments with picosecond time-resolution show that bond breakage in the excited spiro form occurs within less than 2 ps. The primary photoproduct, a non-planar intermediate X*, decays into a mixture of isomers, usually termed "photomerocyanines". The lifetime of the intermediate X*, which varies between 3 and 11 ps, depends both on nature of the solvent and kind of substituent.A fluorescence emission exhibiting a large Stokes shift and a non-exponential decay (tl/c at 1 ns) is attributed to a solvent stabilized intermediate X*', which does not contribute significantly to the formation of the "photomerocyanine" forms. The excited state lifetimes of the dominant merocyanine isomers were determined to be around 10 ps and 800 ps, resp., depending on solvent and substituent.Spontaneous resonance Raman and time-resolved CARS spectroscopy prove the existence of at least two isomeric species in the room-temperature photolyzed solutions. The similarity in vibrational frequencies suggests that corresponding isomeric forms occurring in polar and unpolar solvents, resp., are similar in structure; they differ, however, in Franck-Condon factors for excitation So -Si. The thermodynamic equilibrium distribution of the isomeric "photomerocyanine" species is reached on the time scale of the decay of the intermediate X*.In dieser Arbeit wird zusammenfassend iiber die Ergebnisse von Untersuchungen zur Photochromie von Spironaphthoxazinen berichtet und ein Reaktionsschema vorgeschlagen. Pump-Abfrage-Experimente mit Pikosekunden-Zeitauflosung belegen, daB die Bindung zwischen dem Sauerstoff und dem Spirokohlenstoff in weniger als 2xl0"12s Brought to you by | Universita degli Studi di Padova Authenticated Download Date | 3/29/16 4:11 AM 92 S. Schneider nach der elektronischen Anregung gebrochen wird. Das nicht-planare Zwischenprodukt entsteht in einem angeregten Zustand X*, der je nach Losungsmittel in (3 bis 11) x 10"12 s in ein Isomerengemisch von annahernd planaren, merocyaninartigen Strukturen ubergeht. Nach UV-Anregung der Spiroform wird eine nicht-exponentiell abklingende Emission mit starker Stokes-Verschiebung registriert. Als Ursprung werden besonders solvatisierte Intermediate X*' diskutiert, die nicht effizient in die "Photomerocyanin"-Form zerfallen.Die zeitaufgelosten Resonanz-Raman-und CARS-Spektren belegen die Existenz von mindestens zwei verschiedenen, merocyaninartigen Isomeren in alien Losungsmitteln. Aufgrund der Ahnlichkeit der beobachteten Schwingungsfrequenzen wird geschlossen, daB in polaren und unpolaren Losungsmitteln strukturell sehr ahnliche Isomere vorliegen. Das Isomerenverhaltnis, das der thermodynamischen Gleichgewichtsverteilung entspricht, wird nach UV-Belichtung innerhalb der Zerfallszeit des Intermediaten X* erreicht.Brought to you by | Universita degli Studi di Padova Authenticated Download Date | 3/29/16 4:11 AM

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Investigation of the Photochromic Effect of Spiro [indolino-naphthoxazine] Derivatives by Time-Resolved Spectroscopy

Schneider¹

1987

Zeitschrift Für Physikalische Chemie

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“…Some research groups at IPCP RAS contributed to the design, structural and spectroscopic characterization of photochromic and thermochromic compounds, molecular photoswitches, photoswitchable organic ferromagnets and other types of exciting materials [45][46][47][48][49][50]. Special attention was paid to design of novel materials for photography [51,52], exploration of colloidal systems including gold nanoparticles and quantum dots based on inorganic semiconductors such as CdS, CdSe and PbS [53,54].…”

Section: Introductionmentioning

confidence: 99%

Research in the Field of Organic Photovoltaics at the Institute for Problems of Chemical Physics of Russian Academy of Sciences

Troshin

2015

Organic Photonics and Photovoltaics

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In the present review we highlight the main research activities in the field of organic photonics and photovoltaics at the Institute for Problems of Chemical Physics of Russian Academy of Sciences (IPCP RAS). Extensive investigation of optical and electrical properties of π-conjugated organic compounds performed at IPCP RAS since 1960's resulted in design of many exciting materials representing organic semiconductors, metals and superconductors. Organic Schottky barrier and p/n junction photovoltaic devices constructed at IPCP RAS in 1960's and 1970's were among the first examples of reasonably efficient organic solar cells at that time. These early discoveries inspired younger generations of the researchers to continue the work of their mentors and explore the world of organic materials and photonic devices such as molecular photonic switches, organic light emitting diodes, solar cells, photodetectors, photoswitchable organic field-effect transistors and memory elements.

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“…There is a renewal in interest in the well known photochemical conversion of spiropyrans into transient merocyanines because of the numerous potential applications of these compounds (Milles et a1 1983, Krysanov andAlfimov 1982). Most studies of the photochromic reaction are performed by using ns and ps transient absorption spectroscopy, giving kinetic data but little information about the structure of the transient species involved (Kalisky et al 1983).…”

Section: Introductionmentioning

confidence: 99%

FreeG-sheaves on closed Riemann surfaces

Шварцман¹

1999

Russ. Math. Surv.

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We have designed and constructed a specific time resolved resonance Raman spectrometer for the study of transient species occurring in photochromic reactions. A homemade. low cost integrating video digitiser associated with the SEC camera head of a modified Coderg UF-76 spectrometer and linked to a PDP-I I minicomputer via a serial interface allows the acquisition and analysis of low light level spectra. This apparatus made it possible to investigate directly the structure of transient photoproducts from pyrrolidinospiropyran.

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Ultrafast formation of transients in spiropyran photochromism

Cited by 105 publications

References 6 publications

Investigation of the Photochromic Effect of Spiro [indolino-naphthoxazine] Derivatives by Time-Resolved Spectroscopy

Investigation of the Photochromic Effect of Spiro [indolino-naphthoxazine] Derivatives by Time-Resolved Spectroscopy

Research in the Field of Organic Photovoltaics at the Institute for Problems of Chemical Physics of Russian Academy of Sciences

FreeG-sheaves on closed Riemann surfaces

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