Untitled

Kirillova, S. G.; Andrianov, V. M.; Zhbankov, R. G.

doi:10.1023/a:1025173219936

Cited by 4 publications

(3 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The isolated molecule model was selected for creating the force field of epoxysaccharides [18]. Parameters of potential functions [13,19,20] that were based on numerous x-ray structures and spectroscopic data were used as its starting approximation.…”

supporting

confidence: 88%

Theoretical analysis of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside

et al. 2008

Self Cite

View full text Add to dashboard Cite

A detailed interpretation of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside that is based on complete calculation of normal vibration frequencies and absolute IR absorption band intensities of the molecule and a comparison of the results obtained with the corresponding experimental data is given for the first time. The influence of the epoxy group on the absorption bands characteristic of the pyranose ring has been analyzed.

show abstract

supporting

confidence: 88%

Theoretical analysis of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…As in [5], x-ray diffraction analysis data [11] obtained for β-D-glucose, followed by modeling the groups of atoms and bonds included in the composition of the ether groups on the C6 and C2 atoms (OH → OCH 2 COOH), was used as the initial geometry for the conformational calculations in the molecular mechanics approximation, the parametrization of which has been developed and described in [8][9][10]. Searching for the most probable conformations of the side substituents was based on calculation of the structures obtained by rotating individual portions of the side groups in 10 o steps successively about the bonds C5-C6, C6-O6, C13-O6, C10-C13, C10-O9 (the substituent on the C5 atom of the molecular backbone) and then about the bonds C2-O2, C11-O2, C7-C11, C7-O8 (on the C2 atom, Fig.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Calculation of conformations and vibrational spectra of a monomeric fragment of the 2,6-carboxymethyl cellulose molecule

Andrianov

2007

J Appl Spectrosc

Self Cite

View full text Add to dashboard Cite

A theoretical conformational analysis has been carried out for the side substituents of a fragment of the molecule for 2,6-carboxymethyl cellulose (a water-soluble cellulose ether), and the frequencies and the potential energy distribution of the normal vibrations have been calculated for the most stable conformers of the ether groups of this fragment in the approximation of the molecular mechanics method. It has been shown that the most stable conformers are those that have the conformations analysis of the calculated frequencies and the potential energy distribution of the normal vibrations for 13 of the most stable conformers showed, as in the case of the 2,6-hydroxyethyl cellulose molecule, that the frequencies and modes of the normal vibrations are highly sensitive to conformational transitions in the analyzed spectral region (800-1500 cm -1 ). The characteristic patterns for the change in the frequencies and modes of the normal vibrations have been established in connection with conformational transitions within both side substituents. The observed conformational lability of the bulky substituents in the cellulose ether molecules and its manifestations in the vibrational spectrum provide a basis for hypothesizing that one of the major mechanisms for the process of their thermal gelation in aqueous solutions is conformational transitions within these substituents.Introduction. Water-soluble cellulose ethers have great potential for important practical applications because of their capacity for thermal gelation in aqueous solutions. IR [1-3] and Raman [4] spectroscopy are promising methods for understanding and monitoring these processes. The effectiveness of these methods depends on a proper interpretation of the recorded spectra, a necessary condition for which in the case of cellulose ethers is taking into account the probable conformational states of their bulky substituents, the high conformational flexibility of which we have shown for the example of a fragment of the 2,6-hydroxyethyl cellulose macromolecule (2,6-HEC) in [5]. In [6], it was concluded that an important role is played by conformational conversions of the side groups of cellulose macromolecules and cellulose derivatives during structural transitions, esterification reactions, and forming of final articles based on them. The results of spectroscopic studies have made it possible to conclude that in cellulose ethers, amylose ethers, and other polysaccharide ethers, despite introduction of bulky groups into the structure, the chair conformation of the pyranose ring does not change but rather we observe redistribution of the conformations of the side groups, depending on the degree of esterification and the type of polysaccharide [7]. We may hypothesize that during thermal gelation in aqueous solutions of cellulose ethers, an important role is played by conformational transitions of the ether groups, as a result of which the three-dimensional structure of these polymers changes. We cannot rule out the possibility that one of the major reasons ...

show abstract

“…The research on the spectroscopy and conformations of polysaccharides and model systems was subsequently continued [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The IR Fourier and Raman spectra of the basic types of mono-, di-, and polysaccharides and their derivatives were analyzed in detail (together with Polish colleagues from the Institute of Low Temperatures and Structural Studies, Polish Academy of Sciences, Wroclaw).…”

mentioning

confidence: 99%

Z. A. Rogovin and the development of research in the spectroscopy and conformations of polysaccharides

Zhbankov

2005

Fibre Chem

Self Cite

View full text Add to dashboard Cite

The versatility and originality of Z. A. Rogovins scientific creativity, his temperament, and work capacity significantly affected the evolution of research on the spectroscopy and conformations of polysaccharides, cellulose, in particular, new types of technically valuable derivatives, and on the whole, such a broad class of organic compounds as the carbohydrates.It is important to have a large number of derivatives with additionally incorporated different functional groups for developing research on the spectroscopy of the concrete classes of organic substances. This will allow solving the analytically important problem of setting up a data bank of the characteristic frequencies and intensities to a significant degree. In this respect, collaboration with Z. A. Rogovin and the analysis of the new types and industrially valuable derivatives of cellulose and other polysaccharides obtained under his direction in the Department and in the Problem Laboratory of Chemical Fibres opened up truly unique possibilities. The fact that all of these compounds were obtained for the first time was also especially important. The analysis of their structure and properties and the features of the appearance of the incorporated functional groups in the IR spectra of polysaccharides was pioneering. Since the newly synthesized objects, intermediate products of their synthesis, and model compounds had to be investigated in different aggregate states fibres, films, powders, this made it necessary to develop the optimum methodological conditions of nondestructive spectroscopic analyses.In a comparatively short time, we obtained and interpreted a large number of IR spectra of new types of industrially valuable cellulose derivatives containing chlorine, fluorine, sulfur, and phosphorus atoms, oxime, sulfhydryl, thiocyanate, and other groups, graft copolymers of cellulose with poly-2-methyl-5-vinylpyridine, carbochain polymers, complexing graft copolymers of cellulose with polyacrylohydroxamic acid, etc.The studies of the IR spectra of these compounds were extensively treated in our first monograph Infrared Spectra of Cellulose and Its Derivatives (1964). An updated and expanded version was published in English in New York in 1966 [1, 2]. The spectra of fibrous cellulose materials were obtained for the first time without using immersion media, with the method of direct modeling of fibres obtained abroad, called the Russian method. An extensive table of the characteristic frequencies of the different groups and bonds in the molecules of cellulose and its derivatives and the first atlas of the types of cellulose, products of its physical and chemical modification, the most important types of mono-, di-, and polysaccharides, and polyhydric alcohols is given in the book.The use of IR spectroscopy in this stage led to important conclusions; incorporation of bulky substituents, ester groups in particular, in the structure of cellulose does not lead to the appearance of hydroxyl groups free of hydrogen bonds, as was believed at the time; natural ...

show abstract

Untitled

Cited by 4 publications

References 26 publications

Theoretical analysis of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside

Theoretical analysis of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside

Calculation of conformations and vibrational spectra of a monomeric fragment of the 2,6-carboxymethyl cellulose molecule

Z. A. Rogovin and the development of research in the spectroscopy and conformations of polysaccharides

Contact Info

Product

Resources

About