I. A. Rostovtseva

Spiropyrans and spirooxazines: 11. Complexation of photochromic 5-(1,3-benzothiazol-2-yl)-substituted 1´,3´-dihydrospiro[benzo[f]chromene-3,2´-indole] with metal ions

Abstract5-(1,3-Benzothiazol-2-yl)substituted 1´,3´-dihydrospiro[benzo[f]chromene-3,2´-indole] forms intensely colored complexes with metal ions in acetone solution in the absence of irradiation. The composition and stability of the complexes were shown to depend on the nature of the metal ion. The molecular structure of the zinc complex was determined by X-ray diffraction. The complexes with diamagnetic ions display negative photochromism associated with their reversible dissociation induced by visible light.

Spiropyrans and spirooxazines 10. Synthesis of photochromic 5′-(1,3-benzoxazol-2-yl)-substituted spiro[indoline-naphthopyrans]

New photochromic 5′-(1,3-benzoxazol-2-yl)-substituted spiro[indoline-naphthopyrans] exhibiting luminescent properties in the spirocyclic form were synthesized. Their reverse thermal reaction barrier decreases with the increase in the electron-withdrawing properties of substituent in the indoline fragment.

Quantum-chemical study of spiro[indoline-2,2′-[2 H ]-chromenes] and their complexes with a silver cluster

Computer modeling (DFT B3LYP/6-31G(d,p)/SDD) of the structure and spectral characteristics of photochromic 1,3,3,8′-tetramethyl-6′-formylspiro[indoline-2,2′-[2H]-chromene] and 1,3,3-trimethyl-6′-methoxy-8′-formyl[spiroindoline-2,2′-[2H]-chromene] complexes adsorbed onto the surface of a 10-atom silver cluster has been performed. It has been demonstrated that, depending on the position of the formyl group in the quinoline ring and the isomeric form of the spirocyclic compound, the change in the band intensity in Raman spectra caused by complexation with the silver cluster can reach three orders of magnitude.

Spiropyrans and spirooxazines 12. Synthesis and complexation of a rhodamine-substituted spiro[benzopyran-indoline]

A new spirobenzopyranindoline containing a rhodamine fragment bonded by an azomethine spacer with the benzopyran fragment was synthesized based on 6-formyl-7-hydroxy-substituted spiropyran; the new compound exhibited complexation properties in solutions.

Photodynamic chromogenic system based on photo- and ionochromic 8-(1,3-benzoxazol-2-yl)-substituted spirobenzopyran

Abstract8-(1,3-Benzoxazol-2-yl)-substituted spirobenzopyran is a new chromogenic system in which complexation with metal ions accompanied by a change in color can be controlled by photoirradiation. According to X-ray crystallography, the merocyanine ligand in the zinc complex has the TTT conformation.

Synthesis and complex formation of spirobenzopyranindolines containing rhodamine fragment

The interaction of 7-hydroxy-6-formyl-substituted spiropyrans and Rhodamine B aminoethylamide has afforded spirobenzopyrans containing rhodamine fragment bound to the benzopyran part via the methyleneaminoethyl spacer. The prepared spiropyrans exist in the spiropyran-spirolactam form in the acetone solution and exhibit weak photochromism at 283 K. The addition of Cd, Co, Ni, and Zn perchlorates to the spiropyrans solution results in the coloration due to the complex formation. The composition and stability of the complexes has been determined by means of spectrophotometry.

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 Complex Formation of Rhodamine-Substituted Spirobenzopyranindolines

Novel spirobenzopyranindolines containing a rhodamine fragment linked to a benzopyran fragment with an aminomethylene spacer were synthesized by the reaction of 7-hydroxy-6-formyl-substituted spiropyrans and rhodamine B hydrazide. The synthesized spiropyrans in toluene and acetone are present in the spiropyran‒spirolactam form. The 5-methyl-substituted was the only to exhibit photochromism. Adding Zn(II), Ni(II), Co(II), and Cd(II) perchlorates to the spiropyran solutions leads to intense coloration due to complex formation.

Spiropyrans and spirooxazines 13. Synthesis and photochromic properties of benzoxazolyl-substituted spirobenzopyrans

New benzoxazolyl-substituted spiroindoline-benzopyrans with electron-withdrawing groups in the indoline fragment were obtained. These compounds exhibit positive P- and T-type photochromism. Structural correlations of the spectrokinetic properties depending on the variation of substituents in the indoline part of the spiropyran molecules were established. Electronwithdrawing groups were found to cause a bathochromic shift of the long-wavelength absorption maxima of the merocyanine isomers as compared to the unsubstituted spiropyran and decrease their lifetime. Conversely, an introduction of electron-donating groups results in a hypso chromic shift of the absorption maxima and an increase in the lifetime of the colored isomers of spiropyrans. Electron-withdrawing substituents at the position 5 of the indoline fragment cause the increase of the colorability of the spiropyrans.