Photochromic properties of indoline spiropyrans of the coumarin series

The photochromic properties and aggregation processes of merocyanine forms of indoline spiropyrans of the coumarin series in solutions were studied by spectral and kinetic methods. Photochromism of the compounds synthesized depends on their structure. The efficient formation of J-aggregates was found for indoline spiropyrans 1a,b under UV irradiation and merocyanines 3a,b, which is indicated by the appearance of absorption and fluorescence bands in the visible spectral region and the resonance character of fluorescence. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2350–2356, October, 2005.     

Synthesis and structure of indoline spiropyrans of the coumarin series

New indoline spiropyrans of the coumarin series were synthesized by the condensation of indoline and hydroxyformylcoumarin derivatives. Spiropyrans, viz., derivatives of 8-formyl-7-hydroxy-4-methylcoumarin and 5-formyl-6-hydroxy-4-methylcoumarin, under irradiation are transformed into open forms, which are recyclized in the dark. The compounds formed by the condensation of the indoline derivatives with 3-formyl-4-hydroxycoumarin have an open structure of the merocyanine dyes and are transformed into spiro forms neither in the dark nor under irradiation with the visible light. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2342–2349, October, 2005.     

Photochromism of indoline spiropyrans of the coumarin series in polymeric matrices

The photochromic properties and aggregation processes of merocyanine forms of indoline spiropyrans of the coumarin series in the block and film poly(methyl methacrylate) (PMMA) were studied and compared by spectral and kinetic methods. Photochromism of the synthesized compounds depends on their structure. The efficient formation of J-aggregates was observed for indoline spiropyrans of the coumarin series based on 8-formyl-7-hydroxy-4-methylcoumarin and 3-formyl-4-hydroxycoumarin. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 870–875, May, 2007.     

N-acylamino derivatives of the indoline and tetrahydroquinoline series

Previously unknown N-acylamino derivatives of the indoline and tetrahydroquinoline series were synthesized. Their E,Z-isomerism was studied by NMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 332–336, March, 1990.     

New indoline spiropyrans containing azomethine fragment

The new spiropyran systems with an azomethine bridge were synthesized from a spiropyran containing aminogroup at 6′ position of the benzopyran fragment and substituted aromatic aldehydes. The chemical structure of compounds is confirmed by elemental analysis data, NMR (¹H and ¹³C) and IR spectroscopy. Photochemical studies revealed the presence of photochromic properties at room temperature for one of the obtained spiropyrans.     

Synthesis of 3′-acyl-substituted indoline spiropyrans

The reaction of 1,3,3-trimethyl-ω-formyl-2-methyleneindoline with substituted salicylaldehydes in most organic solvents is accompanied by decarbonylation and gives known spiropyrans that do not contain a formyl group; however, 3′-formyl-substituted spiropyrans can be obtained in low yields in dimethyl sulfoxide. The reaction of 1,3,3-trimethyl-ω-acetyl-2-methyleneindoline with 3-bromo-5-nitrosalicylaldehyde gave a 3′-acetyl-substituted compound in the open merocyanine form with a branched chromophore chain. 3′-Acyl-substituted indoline spiropyrans can be obtained by acylation of the appropriate compounds that do not contain substituents in the 3′ position. Indoline spiropyrans with 3′-acyl substitutents do not have photochromic properties.     

New indoline spiropyrans with highly stable merocyanine forms

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Spectral and luminescent properties of hydroxyazomethines of indoline spiropyrans

Spectral and luminescent properties of novel bifunctional compounds 1–3 based on indole spiropyrans and hydroxyazomethines have been studied in comparison with the properties of the model compounds 5’-substituted spiropyrans and azomethines in organic solvents and PMMA films at 293 and 77 K. Luminescence of compounds 1–3 is due to the presence of the azomethine fragment conjugated with the indoline ring of the spiropyran moiety and determining the long-wavelength absorption band of 1–3. Depending on the solvent, temperature, and the substituent, various combinations of the structures of the chromophore fragments are observed in 1–3: the imine or amine form of the azomethine fragment and the spirocyclic or merocyanine form of the spiropyran fragment.     

Photochromic and thermochromic spiranes. 20.* Photochromic properties of solid-phase films of novel formyl-substituted spiropyrans of the indoline series

We have synthesized novel forrnyl-substituted spiropyrans of the indoline series. We have obtained solid phase amorphous films of the synthesized spiropyrans bv thermal vacuum deposition and established their capacity for photochrornic transformations. We have investigated the effect of the substituents on the spectral properties of the original and colored forms of the solid-phase spiropyran films. We have shown that the kinetic characteristics of the photochromic transformations of these compounds in solid-phase films depend considerably on the bulk of the substituents in the indoline and benzopyran moieties, and also their electron active properties in the latter. Along with reversible processes, in the solid-phase spiropyran films we have observed irreversible photoreactions leading to degradation of the photochromic system.Scientific-Research Institute of Physical and Organic Chemistry, Rostov State University, Rostov-na-Donu 344090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 399–405, March, 1996. Original article submitted February 28, 1996.     

New indoline spiropyrans with π-acceptor substituents in the 8′ position

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1700–1701, December, 1990.     

Styryl-substituted spirochromenes of the indoline series

Styryl-substituted salicylaldehydes were obtained from 5-chloromethylsalicylaldehyde by means of the Wittig reaction, nitration, and several other reactions, and spirochromenes of the indoline series were subsequently synthesized. The possibility of carrying out nitration in the aromatic ring of the benzyl-substituted phosphonium salt and the Wittig reaction at one of the two formyl groups in 5-formylsalicylaldehyde and at the formyl group in the indolinospirochromene molecule is demonstrated. The introduction of a styryl substituent in the chromene part of a photochromic indolinospirochromene gives rise to a significant bathochromic shift of the long-wave absorption band of the photomerocyanine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 207–213, February, 1979.     

DFT modeling of indoline spiropyrans with a cationic substituent in the gas phase

Isomeric forms of indoline spiropyrans show unusual behavior compared with similar compounds, according to experimental data. DFT modeling for gas phase was made to consider the simplest case without environmental effects, which revealed the intramolecular reasons for occurrence of ring opening reaction depending on the particular structure of the compound. The questions of charge redistributions, the changes of geometry and chemical bonds in the structures are also discussed.     

Structure of indoline spiropyrans containing a fused coumarin fragment: Quantum-chemical investigation

In order to examine the way of fusion of the coumarin fragment to the 2H-pyran part of indoline spiropyrans the relative stability was estimated of the cyclic and merocyanine forms by means of calculations in the framework of DFT in B3LYP/6-31G(d,p) approximation. In agreement with the experimental data the relative stabilization of the spirocyclic isomer correlates with the length of the bond where the fusion occurs.     

Some acetylene derivatives of indoline

Conclusions A method was developed for the synthesis of 1-methyl-5-ethynylindoline and its derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1169–1170, May, 1976.     

Synthesis and structure of indoline spiropyrans based on benzo[f]coumarin

Russian Chemical Bulletin - Indoline spiropyrans containing benzo[f]coumarin moiety annulated to the 2H-pyran cycle were synthesized. The obtained compounds exist in solutions as a tautomeric...     

Photo-and thermochromic spiranes 30*. Comparative study by X-ray structural analysis of the structure of spiropyrans of the indoline series containing a condensed furan fragment

The structure of an indoline spiropyran of molecular formula C₂₉H₃₃NO₂ has been studied by X-ray crystallographic analysis. Structural parameters have been determined for this spiropyran, containing a condensed furan fragment with a tert-butyl group, in comparison with the structure of other spiropyrans of this series. The observation in the absorption spectrum of a photoinduced cis-cis isomer is linked with its stabilization by the steric effect of the bulky tert-butyl group and the strength of barriers at 77 K. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 221–228, February, 2008.