N. A. Voloshin

Spiropyrans and spirooxazines 3.* Synthesis of photochromic 5'-(4,5-diphenyl-1,3-oxazol-2-yl)-spiro[indoline-2,3'-naphtho[2,3-b]pyran]

The reaction of 2-hydroxy-3-(4,5-diphenyl-1,3-oxazol-2-yl)-1-naphthaldehyde with 1,2,3,3-tetramethyl-3H-indolium perchlorate afforded photochromic spiro[indoline-2,3′-naphthopyran] containing a 4,5-diphenyloxazole group in position 5′ of the naphthopyran fragment. The merocyanine form of the spiropyran gave complexes with bivalent heavy cations.

Novel Spiropyrans With the Luminescent Larle in the 2H-Chromene Fragment

Abstract A series of novel spirobenaopyrans containing the fluorescent label, 3,5-diphenyl pyrazoline substituent, in the position 7 of the 2H-chromene fragment, has been prepared. The compounds display high efficiencies of the fluorescence (460–490 nm) and have a potential for application as negative luminescent materials for optical storage.

To Estimation of pKa for Spiropyrans of the Indoline Series

A mathematically substantiated approach to estimating acid-base characteristics of spiropyrans of the indoline series with account for the ring-chain tautomerism of these compounds was proposed. The pKa values of spiropyrans of various basicity were estimated.

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.

Photo- and thermochromic spiropyrans 43*. Spectral kinetic study of new benzoxazolyl-substituted spirobenzopyrans

A series of spiroindolinebenzopyrans was prepared, containing a chelating 1,3-benzoxazole group at position 8 of the benzopyran fragment. These new benzoxazolyl-substituted spirobenzopyrans showed photochromic properties in solutions with similar quantum yield values for the direct and reverse photoreactions.

Photochromism of 6′-cyanosubstituted spirooxazines in frozen alcohol matrices

For three 6′-cyanosubstituted spironaphthooxazines, spectral characteristics of an open form and quantum yields of photoisomerization were determined both at room temperature and in frozen alcohol matrices. Spironaphthooxazines have demonstrated fairly high (0.01–0.02) quantum yields of open form appearance at 77 K. The observed peculiarities of the open form UV spectra were explained by the temperature dependence of the open form isomers distribution. Partial stabilization of the nonequilibrium isomers of an open form in the low-temperature matrices was revealed.

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.

Chromogenic Spiroindolinobenzopyrans of the Oxadiazole Series with Photodriven Ionochromic Properties

New photochromic 8-oxadiazolyl-substituted spirobenzopyran-indolines, which are able to undergo light-controllable cation-induced isomerizations, have been obtained.