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 and photochromic properties of spiropyrans containing a fused benzopyranone fragment

New spiro compounds of the indole, phthalazine, isobenzofuran, and benzopyran series, containing a fused benzopyranone fragment in the chromene moiety, were synthesized. Indole derivatives were found to exhibit photochromic properties under stationary conditions at 293 K. The thermal stability of merocyanine isomers sharply decreases upon introduction of electron-withdrawing nitro group into the indole fragment and fusion of a benzene ring to the chromene fragment.     

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.     

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...     

Effect of bulky substituents on the photochromic properties of indoline spiropyrans containing an annelated aromatic or heteroaromatic fragment

Novel indoline spiropyrans containing bulky neopentyl substituents at the nitrogen atom of the indoline fragment were prepared. The structure of the obtained compounds was established by a set of physicochemical methods of analysis. Comparison was made for the spectral absorption and kinetic parameters of the obtained compounds and their analogs containing methyl and benzyl substituents instead of neopentyl ones.     

Synthesis and studies of new photochromic spiropyrans containing a formylcoumarin fragment

A computer search for new photoactive compounds among indoline spiropyrans of coumarin series was carried out using DFT B3LYP/6-31G(d,p) method. Based on the data obtained, the spiropyrans containing a formylcoumarin fragment annulated to the 2H-pyran ring and possessing photochromic properties were synthesized. The structure and photochromism of these compounds were studied by ¹H NMR, IR, and UV/Vis spectroscopy. The introduction of a formyl group into the coumarin moiety of spiropyrans led to a bathochromic shift of the long wavelength absorption maxima of merocyanine isomers, as well as to a considerable increase in their lifetime.     

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.     

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.     

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.     

Preparation of N-methacryloxyethyl derivatives of spiropyrans of the indoline series

Reaction of 2,3,3-trimethylindolenine with ethylene iodohydrin gave 1-hydroxyethyl-2,3,3-trimethylindoleninium iodide, which gives 3a,4,4-trimethyloxazolidino[3,2-a]indoline on treatment with sodium carbonate solution. Condensation of the latter with 5-nitro- and 3-methoxy-5-nitrosalicylaldehydes gives, respectively, N-hydroxyethyl derivatives of 6-nitro- and 6-nitro-8-methoxyspiro(indoline-2,2-benzopyrans) (V, VI), while condensation with 3-nitrosalicylaldehyde gives 4,4-dimethyl-3a-(2-hydroxy-3-nitrostyryl)oxazolidino[3,2-a]indoline (VII). Acylation of nitrospiran V and oxazolidinoindoline VII with methacrylyl chloride in pyridine proceeds at the free hydroxyl groups, while a mixture of derivatives of 1-(-methacryloxyethyl)spiropyran and 3a-(2-methacryloxy-3-nitrostyryl)oxazolidinoindoline is formed under the same conditions from nitromethoxyspiropyran VI. Acylation of V in acetone in the presence of sodium bicarbonate gives 4,4-dimethyl-3a-(2-methacryloxy-5-nitrostyryl)oxazolindo-[3,2-a]indoline. The mechanism of the isomeric transformations of the various forms that contain spiropyran and oxazolidino-indoline rings was studied by means of electronic spectra. The photochromic properties of the spiropyrans were investigated.Communication VI from the series Photochromism of Organic Substances. See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1362–1369, October, 1973.     

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 a new photochromic indoline spiropyran

Conclusions An x-ray diffraction structural study was carried out for the photochromic spirpyran 1,3,3-trimethyl-5-nitrospiro(indoline-2,2-[2H-1]-benzopyran). The C_spiro-O bond in the spiropyran is longer than the normal value but shorter than in the isomeric spiropyran with the nitro group in the benzopyran fragment, which is characterized by a higher quantum yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 191–194, January, 1985.     

Structure and properties of macrocyclic compounds containing a pyrimidine fragment

The structure of a series of macrocyclic compounds consisting of a pyrimidine or 1,3,5-triazine ring and an aza-or thiapolymethylene bridge connecting the N¹ and N³ atoms of the heteroring is discussed. Some macroheterocycles undergo methylation at the sulfur atom by the action of methyl p-toluenesulfonate. The length of the polymethylene bridge determines conformation of the macroring. Compounds with a shorter bridge both in crystal and in solution are characterized by closely located structural fragments, while extension of the polymethylene chain gives rise to an unfolded structure. Conformational changes in solution are promoted by protonation of the bridging nitrogen atom, and deprotonation restores the initial structure of the macroring. The basicity of the bridging nitrogen atom depends on the geometric parameters of the macroring.     

Synthesis of spiropyrans containing an additional chromophore

Spiropyrans of the phenanthridine and indoline series containing phenylazo or benzoylgroups as substituents in the chromene ring were synthesized. These substituents facilitate the formation of deeply colored merocyanine forms in polar solvents. The presence of a phenylazo group causes the intense color of the cyclic forms of the spiropyrans.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1618–1623, December, 1973.