Photodimers of 4'-Substituted 2-Styrylpyridines<sup>1</sup>

Williams, J. L. R.; Carlson, J. M.; Reynolds, G. A.; Adel, R. E.

doi:10.1021/jo01040a040

Cited by 28 publications

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“…The corresponding bis~nethosulfate (XII) did, however, photodimerize in the solid state. inonobasic styrylpyridines were analogous to those of the monoquaternary salts (2). Tables I and I1 summarize the symbols which represent the various derivatives studied in the present work.…”

Section: Introductionmentioning

confidence: 96%

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Photochemical Transformations of Some 4′-Amino-2-Styrylpyridines and Their Salts

Williams¹,

Carlson²,

Adel³

et al. 1965

Can. J. Chem.

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'The photochelllical behavior of 4'-amino-, 4'-dimethylarnino-, 4'-diethylamino-, and 4'-di-n-propylamino-substit~~ted trans-2-styrylpyridine were studied. Ultraviolet irradiation of aqueous solutions of the bishydrochlorides and methiodide-hydrochlorides for moderate periods of time produced mixtures of the corresponding cis and trans isomers. Long irradiation times produced the corresponding dimers in all cases except that of trans-4'-di-n-propylamino-2-styrylpyridine. The cis isomers of the free bases and methiodides were isolated from the cis-trans mixtures. The trans-methiodides are not photochemically labile. The spectra of each pair of isomers were determined in water and in 50% methanol-water, with the exception of the 4'-di-n-propylamino derivative, which is not sufficiently water soluble. In addition, the spectra of the corresponding methiodides, hydrochlorides, bishydrochlorides, and methiodide-hydrochlorides were determined. T h e basic strengths of the nitrogens in the cis-trans isomer pairs of the free bases and methiodides have been determined spectroscopically in water and in 50% methanol-water.

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Section: Introductionmentioning

confidence: 96%

“…Earlier papers (1,2) discussed the photoiso~nerization and photodilnerization of some substituted styrylpyridines. When dinlethylarnino groups were placed in the 4'-position (4-position in the phenyl group), din~erization of trans-2-styrylpyridine lnethiodide (Ia) in the solid state did not take place.…”

Section: Introductionmentioning

confidence: 99%

Photochemical Transformations of Some 4′-Amino-2-Styrylpyridines and Their Salts

Williams¹,

Carlson²,

Adel³

et al. 1965

Can. J. Chem.

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“…The basic strategy we have adopted has been known since 1961 following the contributions of Williams' group. [14][15][16] Their demonstration that the inert 2stilbazole in the solid state photodimerized when its HCl salt was used has been confirmed over a period of forty years by four independent groups with 2-stilbazole and 4-stilbazole. 17- 21 Our interest is in establishing the generality of this reaction by correlating the packing of HCl salt crystals (determined through X-ray crystal structure analysis) with their photoreactivity.…”

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confidence: 95%

Photodimerization of HCl salts of azastilbenes in the solid state

Mondal

Captain

Ramamurthy

2011

Photochem Photobiol Sci

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A simple strategy that is based on conversion of an electron-rich pyridyl to an electron-deficient pyridinium ion is able to orient thirteen of the sixteen olefins investigated towards a single dimer in quantitative yield in the crystalline state. The reagent used is HCl, the method involves grinding the olefin with a drop of HCl and the dimerization is achieved by exposure of the crystalline stilbazolium·HCl salts to light. The weak force involved in modifying the crystal packing is most likely charge-transfer interaction.

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“…On the other hand, no information has concerned the chemical reactivity of the Cy tr H + structure and its absorption and florescence spectra. Also, not enough studies have been reported for the activity of cis form in the literatures, except for the papers of Williams et al, who reported spectroscopic detection of cis and trans isomers on the bishydrochlorides and methiodidehydrochlorides of some 4 \ -amino-2-styrylpyridines by UV irradiation in aqueous and 50% (v/v) MeOH-H 2 O solutions 32,33 . Behera et al synthesized the cis isomer of the hemicyanine dye by a novel method using Ag 2 O as a catalyst 34,35 .…”

Section: Introductionmentioning

confidence: 99%

Absorption, Fluorescence, Photochemical and Thermal cis/trans Isomerization Reactivity of 1-Methyl-4-(4ʹ-aminostyryl)pyridinium Iodide

2015

Chem Sci Trans

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The photo and thermal cis/trans isomerization reactions are studied for 1-methyl-4-(4 ʹaminostyryl)pyridinium iodide, Cy, which is prepared in the trans form. In a basic solution the trans form, Cy tr , cannot isomerise directly to the cis form. Its protonated form, Cy tr H + , is active and reacts photochemically from trans to cis configuration, Cy c H +. The quantum yields Ф tc and Ф ct are determined in water. Deprotonation process of Cy c H + yields the cis isomer, Cy c , which can thermally back to the stable trans form. The rate constants and the activated parameters of the thermal reaction are determined. Due to irreversibility of the thermal reaction, a complete molecular reaction cycle is performed in one direction. To get more information on the spectral characteristics of protonated form, the photochromic of the title compound is studied in different fourteen solvents. The linear relationships between absorption energy with hydrogen bond acceptor ability of the solvents and fluorescence energy of CyH + with free energy for transferring the proton to the solvent, DG t o were determined.

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Photodimers of 4'-Substituted 2-Styrylpyridines¹

Cited by 28 publications

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Photochemical Transformations of Some 4′-Amino-2-Styrylpyridines and Their Salts

Photochemical Transformations of Some 4′-Amino-2-Styrylpyridines and Their Salts

Photodimerization of HCl salts of azastilbenes in the solid state

Absorption, Fluorescence, Photochemical and Thermal cis/trans Isomerization Reactivity of 1-Methyl-4-(4ʹ-aminostyryl)pyridinium Iodide

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Photodimers of 4'-Substituted 2-Styrylpyridines1

Cited by 28 publications

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Photochemical Transformations of Some 4′-Amino-2-Styrylpyridines and Their Salts

Photochemical Transformations of Some 4′-Amino-2-Styrylpyridines and Their Salts

Photodimerization of HCl salts of azastilbenes in the solid state

Absorption, Fluorescence, Photochemical and Thermal cis/trans Isomerization Reactivity of 1-Methyl-4-(4ʹ-aminostyryl)pyridinium Iodide

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Photodimers of 4'-Substituted 2-Styrylpyridines¹