E. V. Solov’eva

PHOTO- AND THERMOCHROMIC SPIRANS 40*. SPIROPYRANS BASED ON 5-BENZOXAZOLYL- 4-HYDROXYISOPHTHALIC ALDEHYDE

Formylation of 2-(2-hydroxyphenyl)benzoxazole gave 5-benzoxazolyl-substituted 4-hydroxyisophthalic aldehyde, which served as a precursor to the synthesis of novel photochromic spiro[indoline-benzopyrans] containing a benzoxazole group at position 8 of the benzopyran moiety. The obtained compounds possess photochromic properties in solution.

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.

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.

Photo- and thermochromic spirans 37.* New symmetrical bisspiropyrans of the indoline series

New symmetrical bisspiropyrans of the indoline series, which have photochromic properties and are characterized by substantially higher absorption capacity of cyclic isomers in comparison to the monospiropyrans, were obtained on the basis of 4,6-dihydroxy-5-methylisophthalaldehyde.

Photo- and thermochromic spirans. 35.* Synthesis and photochromic properties of spiro[indoline-2,3′-pyrano[3,2-f]quinolines] and their cationic derivatives

New photochromic spiropyranoquinolines and their cationic derivatives have been synthesized. Quaternization of the quinoline fragment leads to significant enhancement of the thermal stability of the merocyanine isomers of these cationic spiropyrans.

Spiropyrans and spirooxazines 9. Photochromism of novel cationic spirooxazines

Novel photochromic spirooxazinoquinolines, their cationic derivatives, and cationic spirooxazine containing pyridinium cation in the aliphatic side chain of the oxazine moiety of the molecule were synthesized. Quaternization of the quinoline fragment leads to a substantial increase in the thermal stability of the merocyanine isomers of cationic spirooxazines and a decrease in the efficiency of photocoloration. Pyridinium cation in the aliphatic side chain of the spirooxazine does not exert a substantial effect on the kinetics of photocoloration and thermal bleaching.

Photo- and thermochromic spirans. 38*. New (1-alkyl-4,5-diphenyl)imidazolyl-substituted spirobenzopyrans

3-Diphenylimidazolyl-substituted 2-hydroxybenzaldehyde has been obtained by the formylation of 2-diphenylimidazolyl-substituted phenol. From the obtained compound, new photochromic spiroindolinebenzopyrans containing a 4,5-diphenylimidazole group at the position 8 of the benzopyran fragment were synthesized. The obtained compounds possess photochromic properties in solution.

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.