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Merocyanine Dyes (merocyanine + dye)

Distribution by Scientific Domains
Chemistry80%

Selected Abstracts

Synthetic Potentials of Heptamethine Merocyanine Dyes Containing an Active Chlorine Atom: Reactivity towards Nucleophiles

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2009
Tzveta Gospodova
Abstract The reactivity of heptamethine merocyanine dyes that contain an active chlorine atom at a meso position of the polymethine chain towards nucleophiles is investigated for the first time. The reactivity differs completely from that of cationic cyanine dyes and is consistent with a concerted SNAr addition,elimination mechanism. This mechanism is additionally supported by the performed DFT calculations in the gas phase and in solution. The observed dependence of the reaction on the type of the nucleophilic agents is discussed in terms of Pearson's theory. Additional diversification of and improvement in the stability of the ramified merocyanines is achieved in reactions with methyl-substituted quaternary salts of nitrogen-containing heterocycles. The photophysical characteristics of the novel dyes are reported and compared with those of the parent merocyanine.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Direct Comparison of Highly Efficient Solution- and Vacuum-Processed Organic Solar Cells Based on Merocyanine Dyes

ADVANCED MATERIALS, Issue 37 2010
Nils M. Kronenberg
Identically configured bulk heterojunction organic solar cells based on merocyanine dye donor and fullerene acceptor compounds (see figure) are manufactured either from solution or by vacuum deposition, to enable a direct comparison. Whereas the former approach is more suitable for screening purposes, the latter approach affords higher short-circuit current density and power conversion efficiency. [source]

Synthesis, properties, and solvatochromism of 1,3-dimethyl-5-{(thien-2-yl)-[4-(1-piperidyl) phenyl]methylidene}-(1H,3H)-pyrimidine-2,4,6-trione

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 4 2007
Mohamed El-Sayed
Abstract A new merocyanine dye, 1,3-Dimethyl-5-{(thien-2-yl)-[4-(1-piperidyl)phenyl]methylidene}- (1H, 3H)-pyrimidine-2,4,6-trione 3, has been synthesized by condensation of 2-[4-(piperidyl)benzoyl]thiophene 1 with N,N, -dimethyl barbituric acid 2. The solvatochromic response of 3 dissolved in 26 solvents of different polarity has been measured. The solvent-dependent long-wavelength UV/Vis spectroscopic absorption maxima, vmax, are analyzed using the empirical Kamlet,Taft solvent parameters ,* (dipolarity/polarizability), , (hydrogen-bond donating capacity), and , (hydrogen-bond accepting ability) in terms of the well-established linear solvation energy relationship (LSER): (1) The solvent independent coefficients s, a, and b and (vmax)0 have been determined. The McRae equation and the empirical solvent polarity index, ET(30) have been also used to study the solvatochromism of 3. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Synthetic Potentials of Heptamethine Merocyanine Dyes Containing an Active Chlorine Atom: Reactivity towards Nucleophiles

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2009
Tzveta Gospodova
Abstract The reactivity of heptamethine merocyanine dyes that contain an active chlorine atom at a meso position of the polymethine chain towards nucleophiles is investigated for the first time. The reactivity differs completely from that of cationic cyanine dyes and is consistent with a concerted SNAr addition,elimination mechanism. This mechanism is additionally supported by the performed DFT calculations in the gas phase and in solution. The observed dependence of the reaction on the type of the nucleophilic agents is discussed in terms of Pearson's theory. Additional diversification of and improvement in the stability of the ramified merocyanines is achieved in reactions with methyl-substituted quaternary salts of nitrogen-containing heterocycles. The photophysical characteristics of the novel dyes are reported and compared with those of the parent merocyanine.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Observations on the Synthesis of Photochromic Naphthopyrans

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2003
Christopher D. Gabbutt
Abstract 1-Naphthol reacts with 1,1-diarylprop-2-yn-1-ols 5a,b, under alumina catalysis, by two pathways to give the photochromic naphtho[1,2- b]pyrans 6a,b, together with the propenylidenenaphthalenones 7a,b, representatives of a new class of merocyanine dyes. With 2-methyl-1-naphthol, formation of the photochrome is suppressed; the only products are merocyanines 7c,d. The cyclocondensation of 2-naphthol with 5a,b proceeds much more efficiently, to give the naphtho[2,1- b]pyrans 14a,b. Pyran formation is not suppressed from either 1-bromo- or 1-(4-methoxyphenyl)-2-naphthol; reaction with 5a,b merely results in expulsion of the C-1 substituent. An alternative pathway supervenes in the reaction of 1-methyl-2-naphthol with 5a to give the benz[e]indanone 17, the constitution of which was determined by X-ray crystallography. Reaction of the 1,3,3-triarylpropynols 19a,b with 1-naphthol affords the naphthopyrans 20 together with merocyanines 21, whilst the isomeric pyrans 23 are efficiently produced from 2-naphthol. The configuration of merocyanines 7a and 21a was unequivocally established by X-ray crystallography. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]