V. S. Marevtsev

Photochromic network polymers

New photochromic polymers having network structure have been studied. These polymers have been obtained on the base of spiropyrans (SP) with one or two polymerizable groups. It has been shown that the photochromic properties of SP molecules linked with macromolecules by one polymerizable group depend on supermolecular structure of network polymer. So, these SP molecules can be used as indicators of microheterogeneity of network polymer. It has been established that the photochromic behavior of SP molecules having two polymerizable groups is determined by the number of chemical bonds (one or two) of such a SP molecule with macromolecule. The copolymers of these SP molecules with alkyl methacrylates are of special interest because using these copolymers make it possible to create photochromic polymer material having large and adjustable time of storage of optical information.

Excited-state intramolecular proton transfer in 2,4,5-triarylimidazole molecules

Excited-state intramolecular proton transfer (ESIPT) in the 2,4,5-triarylimidazole molecules was studied by spectral-luminescent technique. For 4,5-diphenyl-(2-hydroxyphenyl)imidazoles, the ESIPT occurs in both liquid and glassy matrices at 77 K. For 4,5-diphenyl-(2-hydroxynaphthyl)imidazole, the ESIPT requires rotation of molecular fragments and is not observed at 77 K.

Merocyanine form of photochromic spirooxazines in acid solutions

Electronic absorption and NMR spectra of solutions of photochromic spironaphthoxazines (SNOs) were studied. The addition of an acid results in the formation of a salt of the colored form of SNO. For SNOs with nitrogen-containing electron-releasing substituents, the structure of the product that formed depends on the acid concentration being the salt of the mono- or dication.

Luminescence of stereoisomers of the open form of spiropyran in polymer films

ConclusionsPhotocoloration of spyropyran in polymethyl methacrylate and polystyrene matrices at 293 and 77 K results in the formation of a set of photoproducts with individual spectral characteristics, and the structure of a certain stereoisomer was assigned to each photoproduct based on these characteristics.

Photochromic properties of indolinospironaphthooxazine in polymeric films

Conclusions1.The processes of the photocoloration and dark decoloration of indolinospironaphthooxazine in polymeric films are described on the assumption of the existence of two types of molecules of the initial and colored forms. The quantum yields of the photocoloration, the rate constants, and the energy of activation of the decoloration reaction are determined.2.A photophysical mechanism for the process of the photocoloration of indolinospironaphthooxazine, including the participation of the cis-cisoid isomer, is proposed.

Correlation equation for the activation free energy of the inversion of configuration in the closed form of indolinospiropyrans

Conclusions1.A correlation equation was obtained for the active free energy ΔG≠ for the thermal inversion of configuration of the closed form of spiropyrans substituted both in the indoline and benzopyran fragments.2.The nN—σCO* orbital interaction plays the major role in determining the magnitude of ΔG≠ and the strength of the C2-O bond.

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.

Synthesis and photochromic properties of spiro (benzindoline-naphthoxazines)

A new photochromic compound belonging to the class of spiro(indoline-naphthoxazines) was synthesized. Nitration of this compound was carried out and the structures of two photochromic nitro-substituted products were determined. The photochromic properties of the products were studied in solvents of different polarity.

Synthesis and photochromic properties of nitro-substituted spironaphthooxazines

Abstract7-Nitro- and 8-nitroderivatives of 1′,3′,3′-trimethylspiro[indoline-2′,3-3H-naphtho[2,1-b][1,4]oxazine] were synthesized, the last of them being prepared by direct nitration. The introduction of the nitro group stabilizes a bipolar colored form, the highest stability being exhibited when the NO2 group is the 8-position.

Direct Nitration Reactions of Photochromic Spirooxazines

ABSTRACT A direct nitration of photochromic spirooxazines was carried out by three different methods. The molecular structure of main products was determined by NMR 1H and 13C spectra. The nitration mechanisms were proposed. It was shown that only nitration by mixture of nitric and sulfuric acids gives photochromic compounds with nitrogroup in aryloxazine ring.