Crown Ether Styryl Dyes

The mechanisms of regioselective and stereoselective 2 -E 2-photocycloadditions have been extensively reviewed. The intramolecular 2 -E 2-photocycloaddition of 2-allyl-2-(l//)-naphthalenone (13) on the surface of silica produces all four cycloadducts (14)-(17) (Scheme 4). ° Molecular mechanics have been used to study the regio- and stereo-selectivity of the 2 -E 2-photocycloadditions in complexes containing crown ether styryl dyes and alkaline earth metal cations."... 

It was found that the linking of styryl dye fragment to benzocrown ether results in novel photochromic compounds CESD (Crown Ether Styryl Dyes) possessing interesting physico-chemical properties (Scheme 1) [13], The dyes are intensively colored and show significant hypsochromic shifts upon complexation with alkaline earth metal cations in acetonitrile solution. Reversible photochemical reaction E,Z-isomerization is observed for both dyes and their complexes. 

This idea was realized using crown ether styryl dyes (CESD) lc,d, 4c (Scheme 1,4). The compounds lc,d, 4c having betaine structures form supramolecular dimers with a crossed arrangement of molecules (a h-head-to-tail) in the presence of ions, due to the intermolecular interaction between the sulfo group of one of the molecules and a ion located in the crown-ether cavity of the other molecule [20,21], It was shown that photoirradiation of solutions of dimer results in stereospecific PCA giving only one of the 11 possible derivatives of cyclobutane, which is expected in conformity with the concerted superficial (s,s) addition of the reactants (Scheme 5) [22,23], It is noteworthy... 

Gromov, S.P., Alfimov, M.V. (1992) Supramolecular photochemistry of the crown ether styryl dyes, Russ. Chem. Bull., 46, 611-636. 

Gromov, S.P., Fedorova, O.A., Ushakov, E.N., Baskin, I.I., Lindeman, A.V., Malysheva, E.V., Balashova, T.A, Arsen ev, A., Alfimov, M.V. (1998) Crown ether styryl dyes. 24. Synthesis of multiphotochromic 15-crown-5 ethers with rigid spacers, their anion- capped complexes, and stereospecific 1212 -autophotocycloaddition, Russ. Chem. Bull., 47, 97-105. 

Interest in cationic photopolymerisations has increased dramatically over the last year. Novel crown ether styryl dyes have been developed for 2+2 cycloaddition reactions while a tris(2,2 -bipyridyl)ruthenium complex has been successful in inducing the photopolymerisation of aniline. New hybrid vinyl... 

Scheme 4). ° Molecular mechanics have been used to study the regio- and stereo-selectivity of the 2 -E 2-photocycloadditions in complexes containing crown ether styryl dyes and alkaline earth metal cations."... 

ABSTRACT. The structure of crown ether styryl dyes representing a novel class of dyes is considered. Data on absorption and fluorescence spectra as well as photoisomerization and complexation of photochromic 15-crown-5-ethers are analyzed. The results are exhibited concerning dimerization of the complexes incorporating trans- and cis-isomers of the compounds obtained and stereospecificity of photoinduced cyclodimerization of the latter with formation of cyclobutane derivatives. 

We have performed a synthesis of indolenine styryl dyes la,b [11,12] and styryl dyes of benzothiazole series 2a-d [13,14]. Compound lb contains a fragment of crown ether, and perchlorate 2-[2- 3,4-dimethoxyphenyl)ethenyl]indolinium (la) has in a benzene cycle two methoxygroups which reproduce in general terms electron-donating effect of a crown ether substituent on the dye conjugated double bonds. However, in contrast to crown ether styryl dye lb, compound la should not be noticeably capable of complexation with ions of alkaline and alkaline earth metals. 

The molecules of a crown ether styryl dye have been discovered to be arranged in monocrystal in pairs according to "head-to-tail" type so as to make ethylene bonds be situated one above the other. By analogy, the existence of dye molecules in dimeric form could be suggested for the solutions too. Later on we have discovered the susceptibility of crown ether styryl dyes to the formation of dimer in solutions [16]. 

We studied quick stages of structural dynamics of crown ether styryl dyes by the method of picosecond fluorescence spectroscopy. It was found that the observed dependence of fluorescence lifetime on the solvent viscosity could be described by the barrier model of the trans-cis isomerization occurring in the existed singlet electron state [19]. 

Spontaneous molecular self-organization is based on the molecules obtained capable of forming of themselves a desired supramolecular architecture. The studies on photochemical transformations of crown ether styryl dyes representing a novel class of bifunctional dyes and chosen as an example allow us to demonstrate for the first time two step molecular self-organization. The first step of the process includes self-organization of dye molecules into dimers in the course of complexation. The second step comprises photoinduced pre-organization of dye complexes... 

Gromov, Sergei P., Fedorova, Olga A., Ushakov, Evgeny N., Stanislavsky, Oleg B., and Alfimov, Michail V. 1991 Crown ether styryl dyes. 4. Size of chelate macrocycle and complexation of cis-isomers of photochromic 15-crown-5-ether betaine , Dokl. Acad. Nauk SSSR 321, 104-107. 

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