β-Cyclodextrin forms the 1:1 inclusion complex with Crystal Violet, Methylene Blue, Methyl Orange, or Congo Red in water. On the other hand, γ-cyclodextrin forms the 1:2 complex with Crystal Violet, Methylene Blue, or Methyl Orange, while the 1:1 complex is given with Congo Red. The one host-two guest complexations are shown on the bases of the changes of the electronic spectra, dependence of induced circular dichroisms on the concentrations of dyes, and the continuous variation methods with induced circular dichroism. The dissociation constants for the 1:2 complexes are determined with the improved Benesi-Hildebrand equation. Alternation between the 1:1 and 1:2 complexation is discussed in terms of the cavity size of cyclodextrin and the aggregation character of dye.
β-Cyclodextrin (β-CyD) was immobilized by crosslinking with 1,2-ethanediol diglycidyl ether, 1,4-buthanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,3-butadiene diepoxide, 1,7-octadiene diepoxide, and epichlorohydrin. The molar ratio of the crosslinking residue to β-CyD (degree of crosslinking) for each macromolecular product was determined by the corresponding elemental analysis. The equilibrium constant K of complex formation of each crosslinking macromolecule for cresols, phenol, nitrophenols, and 2-naphthol was determined, respectively, by the use of electronic absorption spectroscopy in pH 4 and 10 (or 11) buffer solutions. The concept of a hydrophobic enhancement coefficient R was introduced in order to compare the effect of a hydrophobic crosslinking residue upon the complex formation of the immobilized CyD.
A novel method for preparing Prussian Blue (PB) films cast from a PB solution of organic solvent containing cationic surfactants is reported. The cyclic voltammogram for the oxidation of the film is much simpler than that of an electrochemically deposited PB film. The electrochromic behavior was investigated by in-situ UV-VIS spectroscopy.
Interactions of monomer forms of protoporphyrin IX, deuteroporphyrin IX, hematoporphyrin IX, and coproporphyrin III, respectively, with α- and γ-cyclodextrin in 0.002 mol·dm−3 NaOH aqueous solution are indicated by change of electronic spectrum and induction of circular dichroism. Dimerization constant of porphyrin and complex formation constant of porphyrin with cyclodextrin are also determined from the electronic spectra.
The reversible electrochromism in the thin films of single-transition metal phthalocyanines is reported. Copper and nickel phthalocyanine films can be oxidized and rereduced reversibly, when the film is enough thin, the scan range is well controlled, and the appropriate anion is used as the electrolyte. Especially, the cyclic voltammogram of nickel phthalocyanine films in a sodium nitrate solution is almost Nernstian.
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