Natalya A Vodolazkaya

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The stepwise ionization (H(3)R(+) <==> H(2)R <==> HR(-) <==> R(2-)) of four fluorescein fluoro derivatives was studied by visible spectroscopy. The pK(a) values were determined in water, in 50 mass % aqueous ethanol, in oil-in-water microemulsions (benzene + CTAB + pentanol-1 in water with 1.0 M KCl; CTAB = cetyltrimethylammonium bromide), and in reversed(More)
In this paper, we compare the properties of SiO(2)/water interface modified by cetyltrimethylammonium bromide (CTAB) with those of CTAB spherical micelles. The suspension of uniform silica nanoparticles coated with CTAB adlayer was investigated by using a set of acid-base indicators. The study of the colloidal system has been provided using electron(More)
Among the vast set of fluorescein derivatives, the double charged R2- anions of aminofluoresceins are known to exhibit only low quantum yields of fluorescence, [Formula: see text]. The [Formula: see text] value becomes as high as that of the fluorescein dianion when the lone electron pair of the amino group is involved in a covalent bond. According to(More)
In this paper, we demonstrate that the behavior of a set of eight large-sized negatively solvatochromic pyridinium N-phenolate betaine dyes reflects the principle transformations, occurring in aqueous micellar solutions of three cationic surfactants. As surfactants, cetyltrimethylammonium bromide (CTAB), n-octadecyltrimethylammonium chloride (OTAC), and(More)
Among different types of calixarenes, the water–soluble ones are of especial interest because of their possible applications in biochemical research. In order to elucidate the nature of aqueous solutions of a cationic amphiphilic calixarene, substituted tetrapropoxy-calix[4]arene bearing hydrophilic choline groups at the upper rim, we studied vis–(More)
Stepwise dissociation and tautomerism of 2,4,5,7-tetranitrofluorescein (TNF) were studied by using vis-spectroscopy in dimethylsulfoxide (DMSO), in aqueous acetone, and in cetyl-trimethylammonium chloride (CTAC) micellar solutions at ionic strength of the bulk phase 4.00M KCl. The pK(a) values in DMSO and 90 mass% (CH3)2CO as well as the 'apparent'pK(a)(a)(More)
The protolytic equilibrium of fluorescein in aqueous solutions was studied in the presence of cycloheptaamylose (beta-cyclodextrin, or beta-CD). The constants of stepwise ionization of the dye (H(3)R(+)left arrow over right arrowH(2)Rleft arrow over right arrow HR(-)left arrow over right arrowR(2-)), K(a0), K(a1), and K(a2) were determined using(More)
Rhodamine dyes are widely used as molecular probes in different fields of science. The aim of this paper was to ascertain to what extent the structural peculiarities of the compounds influence their absorption, emission, and acid-base properties under unified conditions. The acid-base dissociation (HR(+)⇄R+H(+)) of a series of rhodamine dyes was studied in(More)
This paper reports the spectral properties and protolytic behavior of the fluorescent dye N,N'-dioctadecylrhodamine on the micelle/water and microdroplet/water interfaces as well as in Langmuir-Blodgett films soaked into aqueous media. Long hydrocarbon chains provide similar orientation of its cation and zwitterion, with the dissociating group(More)
Aqueous solutions of four cationic poly(propylenimine) low-generation dendrimers of different architecture and hydrophobicity have been examined as media for acid-base reactions of indicator dyes. The cationic dendrimers in solution can be considered as oligomers of cationic polyelectrolytes, or surfactant-like species, able to form micelles through(More)
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