Photochromic Dihetarylethenes: XVII. New Synthesis of Photochromic N-Alkyldithienylmaleimides

A new convenient procedure for the synthesis of photochromic N-alkyldithienylmaleimides was developed on the basis of the reaction of 3,4-bis(2,5-dimethyl-3-thienyl)furan-2,5-dione with primary amines. Photochromic properties of the products were examined.     

Photochromic dihetarylethenes. 6. Photochromic derivatives of thieno[3,2-b]thiophene

1,2-Bis{5-(2-benzothiazolyl)-2-methyl-6-trifluoromethylthieno[3,2-b]thiophen-3-yl}hexafluorocyclopentene possessing high fatigue resistance was synthesized for the first time. Its photochromic and fluorescence properties were studied. The structure of its cyclic form was established by X-ray diffraction analysis.     

Photochromic dihetarylethenes

The structures of two hetarylethene photochromes,viz., 1,2-bis(2-ethyl-5-ethylsulfonylthien-3-yl)perfluorocyclopentene and 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene, were established by X-ray diffraction analysis. The conformational parameters of the title compounds are considered. The cyclopentene ring in the former compound is planar and this ring in the latter compound adopts an envelope conformation. There are no overall conjugated systems in the molecules under study. In both structures, the dihetaryl fragments are rotated with respect to the perfluorocyclopentene fragments by ∼55°. The thiophene and benzoxazole rings in 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene are coplanar. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 74–77, January, 2000.     

Photochromic Dihetarylethenes: XX. Synthesis and Photochromic Properties of Dithienylethenes with a Fixed Conformation

>A procedure was developed for the synthesis of bis(2,5-dimethyl-3-thienyl)ethenes with partially fixed molecular conformation, and their photochromic properties in solution were studied. The structure of photochromic 1-(2,5-dimethyl-3-thienyl)-7,9-dimethyl-5,6-dihydrothieno[3',4' : 3,4]pyrido[1,2-c][1,3]oxazol-3-one, as well as of 1-(2,5-dimethyl-3-thienyl)-7,9-dimethylthieno[3',4' : 3,4]pyrido[1,2-c][1,3]oxazol-3-one possessing no photochromic properties, was determined by X-ray analysis.     

Photochromic dihetarylethenes

A series of new photochromic compounds were obtained for the first time from 1,2-bis(2-ethylthio-3-thienyl)perfluorocyclopentene by substituting bromine atoms or carboxy, alkoxycarbonyl, and carbamoyl groups for hydrogen atoms in positions 4 and 4′. Introduction of these substituents causes a slight bathochromic shift (by 20–30 nm) of a long-wavelength absorption band for the cyclic form and significantly increases the quantum yields of photocyclization Ф_A→B and ring opening Ф_B→A. Depending on the nature of a substituent, Ф_A→B decreases in the order COOH>COOMe>CONHAr. The quantum yields are markedly reduced when the ethylthio groups in positions 5 and 5′ are replaced by ethylsulfonyl groups (a tenfold reduction in Ф_A→B and a four- to fivefold reduction in Ф_B→A) The most considerable bathochromic shift of a long-wavelength band and the highest quantum yields of forward and reverse photoreactions were observed for 1,2-bis(4-bromo-2-ethylthio-3-thienyl) perfluorocyclopentene. 1,2- Bis (2-ethyl-5-ethylthio-4-methoxycarbonyl-3-thienyl)perfluorocyclopentene was structurally characterized by X-ray diffraction analysis.     

Photochromic Dihetarylethylenes. 22. Synthesis and Photochromic Properties of Unsymmetrical Alkylthio-substituted 1,2-Bis(dithienyl)perfluorocyclopentenes

Certain unsymmetrical 1,2-bis(dithienyl)perfluorocyclopentenes have been synthesized containing alkylthio, bromo, carboxy, and benzothiazolyl substituents in the thiophene rings. It was shown that on irradiation with UV light they all display photochromic properties, with the exception of the derivative containing an alkylthio group in the reaction center of one of the thiophene rings.For the anniversary of Academician N. K. Kochetkov.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 691–696, May, 2005.     

Photochromic dihetarylethenes

1,2-Bis[2-methyl-5-(benzoxazol-2-yl)thien-3-yl]hexafluorocyclopentene was synthesized, and its photochronic properties were studied For Part 2, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1011–1014, May, 1999.     

Photochromic dihetarylethenes

The structures of two hetarylethene photochromes,viz., 1,2-bis(2-ethyl-5-ethylsulfonylthien-3-yl)perfluorocyclopentene and 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene, were established by X-ray diffraction analysis. The conformational parameters of the title compounds are considered. The cyclopentene ring in the former compound is planar and this ring in the latter compound adopts an envelope conformation. There are no overall conjugated systems in the molecules under study. In both structures, the dihetaryl fragments are rotated with respect to the perfluorocyclopentene fragments by ∼55°. The thiophene and benzoxazole rings in 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene are coplanar. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 74–77, January, 2000.     

Photochromic polypeptides

Two photochromic polypeptides were synthesized by reaction of 1-(4-iodobutyl)-3,3- dimethylindolindolino-6′-nitrobenzospiropyran with poly-L -tyrosine; their molar contents on photochromic units were 27.3 and 44.7%. The spectra of the photo-induced merocyanines and their decoloration kinetics were compared with these of the monomeric model compound, obtained by reaction of the same N-(4-iodobutyl)-indolinospiropyran derivative with N-acetyltyrosine methyl ester. Different types of solvents have been examined, mainly dimethylformamide and pyridine, acetone and tetrahydrofuran, and methanol and ethylene glycol. The polypeptides showed a much less pronounced solvatochromism than their model; on the other hand, their absorption spectra presented two absorption maxima instead of one for the model. These differences in photochromic behavior were interpreted on the basis of the solvatation of the polymeric chain. Inverse photochromism was observed for polypeptide P₂ as well as for the model in ethylene glycol solution; this effect is due to a higher merocyanine content at the thermal equilibrium spiropyran ? merocyanine in high polar solvent.     

Synthesis of Photochromic Dihetarylethenes. (Review)

The main methods of synthesis of dihetarylethenes are given in the review. Approaches for obtaining photochromic compounds are discussed, in which both the traditional residues of perfluorocyclopentene, maleic anhydride, and maleimide, and little-studied fragments of partially saturated or aromatic heterocycles are used as the ethenic fragment. Significant attention is paid to the X-ray structural data of open and cyclized forms of the photochromes.     

Photochromic dihetarylethenes. 9. Dithienylperfluorocyclopentenes: a quantum-chemical study

MNDO calculations of the open and cyclic forms of the molecules of three photochromic 1,2-di(3-thienyl)perfluorocyclopentene derivatives were carried out. Structural parameters as well as electronic and thermodynamic characteristics of the compounds studied were analyzed. The optimized geometric parameters of the open forms of the three molecules under study are in satisfactory agreement with the results of X-ray diffraction studies. Analysis of the effect of substituents on the electronic characteristics of the central fragment and on the composition of the frontier MOs suggests that it is more appropriate to use cyclic rather than open forms of the molecules for correlation analysis and for prediction of photochromism of dithienylperfluorocyclopentenes.     

Photochromic crown ethers

An amphiphilic crown-containing styryl dye (1) was synthesized, and the effects of irradiation, temperature, and alkali and alkali-earth metal ions on the conductivity and optical spectra of its solutions in dioctyl phthalate were studied. Compound1 in thetrans-form almost completely exists as ion pairs (IP). Irradiation at a long-wavelength absorption maximum (λ_max) results in a reversible increase in the conductivity and, hence, a degree of dissociation of IP (α); these parameters decrease when complexes with metal ions are formed. The relaxation times for the photoinduced conductivity coincide with a decrease in the extinction within experimental error in the 20–60°C temperature range. The photoinduced increase in α is caused bytrans—cis-isomerization and an increase in steric hindrances for the interaction of the ClO₄ ⁻ anion with the N⁺ atom of benzothiazolium in thecis-form of1. The activation energies for the darkcis—trans-relaxation, absolute α values, and thermodynamic parameters of dissociation of IP in thetrans-form, as well as the α values in a photostationary mixture ofcis—trans-isomers, were estimated. The decrease in α after binding with metal ions is likely caused by the redistribution of the positive charge to benzothiazolium through the conjugated system of1. Correlations between the decrease in conductivity (decrease in α) and the hypsochromic shift Δλ_max after the formation of complexes between1 and metal ions were observed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1296–1301, July, 1997.     

有机光致变色材料

有机光致变色材料作为一种新型功能材料,已应用在高科技领域和民用领域.本文简单介绍它的光致变色机理、主要的光致变色体系和有机光致变色材料在各种领域的应用.     

Photochromic coumarin spiropyrans

New photochromic spiropyrans (SPP) derived from 4-methyl-7-hydroxy-8-formylcoumarin have been synthesized. The effect of the heterene fragment on the spectral and photochromic properties of the SPP was examined. The photoproduct of the benzodithiolane SPP had the absorption with longest wavelength. Indoline SPP were found to have the most efficient photocoloring. Fluorescence of the cyclic form was found for the SPP.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 601–604, May, 1992     

多功能光致变色化合物

有机光致变色化合物是一种新型有机功能化合物,可广泛应用于光存储、光开关和光转换器件等领域,本文综述近几年来双光致变色化合物体系及具有荧光性能、磁性能等多功能光致变色化合物体系的研究进展,并对有机光致变色化合物的研究应用做了展望。     

Photochromic 2-pyrrylfulgides

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1137–1138, August, 1990.     

Photochromic Dihetarylethenes. 12. Synthesis of 5-Alkyl-2-(1,3,4-oxadiazol-2-yl)thiophenes and Their Photochromic Derivatives

Photochromic derivatives of 5-alkyl-2-(1,3,4-oxadiazol-2-yl)thiophenes have been synthesized for the first time. Their photochromic and fluorescent properties have been studied.