B. S. Lukyanov

Effect of complexation with lanthanide metal ions on the photochromism of (1,3,3-trimethyl-5′-hydroxy-6′-formyl- indoline-spiro2,2′-[2h]chromene) in different media

Complexation of lanthanide ions {Ln(III) ions [Tb(III), Eu(III), or Sm(III)]} with the spiropyran-derived merocyanine obtained in dark and under steady irradiation of indoline spiropyran (1,3,3-trimethyl-5′-hydroxy-6′-formyl-indoline-spiro-2,2′-[2H]chromene) induces a noticeable hypsochromic shift of about 10–110 nm of its visible absorption band concomitant with hypochromic effect and influences its thermal bleaching in the dark. The effect of lanthanide ions and medium on photochromic, spectral-and-kinetic, and luminescence properties of the spiropyran and its complexes in solution and polymer matrix of polymethylmethacrylate (PMMA) is studied. Efficient energy transfer from the spiropyran moiety results in efficient typical luminescence from the Ln(III) ion that becomes more pronounced in polar nonalcoholic solvents and PMMA solid matrix. Moreover, luminescence mappings for pattern recognition analysis have been obtained from which the nature of the solvent and/or the ligand is clearly identified.

Synthesis of Novel Iono- and Photochromic Spiropyrans Derived from 6,7-Dihydroxy-8-Formyl-4-Methyl-2H-Chromene-2-One

�-hydroxy group were synthesized and their spectral properties as well as abilities for complexation with metal ions studied. In solutions they exist as equilibrium mixture of spirocyclic (A) and merocyanine (B) isomers. The largest content of merocyanine form was found for the derivative with an electron-donating methyl group in position 5 of hetaryl fragment. The irradiation of SPPs in acetonitrile shifts the equilibrium to the B form. Similar effect causes the addition of metal cations due to formation of colored complexes with merocyanine isomers.

Solid state photochromism of spiropyrans

A series of spiropyrans possessing photochromic properties in solid state were investigated. UV irradiation (λmax=365 nm) of the thin vacuum deposited spiropyran films results in conversion of the colorless form to the photocolored one. The reaction is photochemically and thermally reversible. The photochromic activity of the solid material and polystyrene matrix has been compared. Raman spectroscopy has been used for studying the influence of metallic surface on the adsorbed spiropyran layers.

Photo-and thermochromic spiranes. 24*. Novel photochromic spiropyrans from 2,4 -dihydroxyisophthalaldehyde

Novel series of photochromic indoline and benzoxazine spiropyrans containing ortho-placed formyl and hydroxyl groups in the benzene ring of the chromene part of the molecule have been prepared. X-ray analysis has shown that, depending on the structure of the heterocyclic component in the spiro cyclization reaction different, nonequivalent formyl groups of 2,4-dihydroxyisophthalaldehyde can participate. The synthesized compounds were used as original analogs of salicylaldehyde. The novel photochromic bispyropyrans prepared contain two different asymmetric spiro carbon atoms.

Photo-and thermochromic spiranes. 29. New photochromic indolinospiropyrans containing a quinoline fragment

A new photochromic spiropyran of the indoline series, containing a quinoline fragment, has been synthesized. The photochromic properties of the spiropyran and its iodomethylate have been studied. Features of the molecular structure of the compounds were determined by X-ray structural investigations. It was established that the pyridopyran fragments of the cations in the crystal of the iodomethylate salt, unlike those in the crystal of the neutral spiropyran, emerge from 21-stacks, disposed jointly with I− ions, which causes their higher mobility and aids the course of reversible photoconversions on UV irradiation in solution.

Photochromic and thermochromic spirans: VII. Spiro(4-oxo-3,4-dihydro-2H-1,3-benzoxazin-2,2?-[2H]benzophyrans)

New spiropyrans of the 4-oxo-3,4-dihydro-2H-1,3-benzoxazine series, individual representatives of which have photochromic properties, were obtained by condensation of 2-alkyl-4-oxo-1,3-benzoxazinium perchlorates with aromatic o-hydroxy aldehydes in acetic acid and subsequent treatment of the 2-(o-hydroxystyryl) derivatives with pyridine or triethylamine. The structures of the synthesized compounds were confirmed by the PMR, IR, and UV spectroscopic data.

Studies of structure and photochromic properties of spiropyrans based on 4,6-diformyl-2-methylresorcinol

Indoline-derived spiropyrans, the precursors of nonsymmetric bis-spiropyrans, which are the promising prototypes of multistate molecular switches, were synthesized based on 4,6-diformyl-2-methylresorcinol. Molecular structure of one of these compounds was studied by X-ray diffraction analysis. Photochemical studies showed the presence of photochromic properties in the obtained spiropyrans at room temperature.

The Effect of Tb and Sm Ions on the Photochromic Behavior of Two Spiropyrans of Benzoxazine Series in Solution

The photochromism of [7-hydroxy-8-formyl-3-methyl-4-oxospiro[1,3-benzoxazin-2,2-[2H-1]benzopyran],SP(I),[7-hydroxy-8-formyl-3-benzyl-4-oxospiro[1,3-benzoxazin-2,2-[2H-1]benzopyran] SP(II) and their coordination with Tb3

Spiropyrans Containing the Reactive Substituents in the 2H-Chromene Moiety

Some spiropyrans containing functional substituents in the [2H]-chromene part of the molecule were synthesized and their photochromic properties in solution and solid state were investigated. The presence of the formyl group in the [2H]-chromene fragment enhances the possibility to show photochromic properties in solution.

Photo- and thermochromic spirans

New spiropyrans with π-acceptor azomethine and ketovinyl substituents in the 8′ position were synthesized using the functional possibilities of the carbonyl group. The structures of the compounds obtained and their photochromic properties in 2-propanol at −70°C were studied.