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New asymmetrical pyridyl-BODIPY dyes with a meso-CF3-group were synthesized by condensation of trifluoro-1-(5-phenylpyrrol-2-yl)ethanol with 2-(2-, 3- or 4-pyridyl)pyrroles, followed by the oxidation and formation of a complex with BF3 etherate. The molecular and crystal structures of these compounds were studied by DFT calculations and single-crystal X-ray diffraction analysis. The absorption and fluorescence properties of the synthesized dyes in polar and nonpolar media were quantitatively characterized. In this work, the efficiency of dye adsorption on CdSe colloidal quantum dots was studied, and the influence of the nitrogen atom position in the pyridyl group on the stability of the resulting associates was shown. [ABSTRACT FROM AUTHOR]

E-Isomers of styryl dyes containing a benzo-18-crown-6 ether or N-methylbenzoaza-18-crown-6 ether moiety and a benzothiazolium residue with an ammoniohexyl, ammoniopentyl, or ammoniomethylbenzyl N-substituent were synthesized. According to spectrophotometry and NMR spectroscopy data, dyes of this type are capable of self-assembly in MeCN to form dimeric complexes, which have a pseudocyclic structure owing to double intermolecular ammonium cation–crown ether interactions via hydrogen bonds; the dimerization equilibrium constants were measured. It was shown that photoinduced Z-isomers of the dyes are capable of intramolecular complex formation between the ammonium cation and the crown ether moiety; therefore, upon E→Z photoisomerization, the dimer–monomer equilibrium shifts towards the pseudocyclic monomer. Data on the relative stability of the intramolecular cation-capped complexes formed by Z-isomers were obtained. It was shown that the equilibrium constants for the Ba2+ complexation with E-isomers of the dyes are almost three orders of magnitude higher than those for that with Z-isomers, which may imply the applicability of these dyes as photoswitchable supramolecular devices. [ABSTRACT FROM AUTHOR]