Molécules modèles des motifs des poly-1,4-glucosides. II. Etude, par spectroscopie infrarouge, des conformations chélatées des diastéréoisomères modèles et discussion dans le cadre des chélations glucosidiques

1978 ◽  
Vol 56 (15) ◽  
pp. 2076-2085 ◽  
Author(s):  
Françoise Lafuma ◽  
Claude Quivoron
Keyword(s):  
Carbon Tetrachloride ◽  
Single Molecule ◽  
Infrared Spectra ◽  
Systematic Study ◽  
Experimental Results ◽  
Hydroxyl Groups ◽  
Dilute Solution ◽  
Absorption Bands ◽  
Model Molecule

We have made a systematic study of the infrared spectra, in the chelation region 3700–3300 cm−1, of each of 30 separate diastereoisomers in dilute solution in carbon tetrachloride. Those diastereoisomers which have configurations corresponding to those of cellulose or amylose were examined more carefully. Depending on the structure of the model molecule and its diastereoisomeric configuration, it was possible to observe absorption bands corresponding to chelation in rings of 5, 6, 7 or 8 members. Most frequently the geometry of the chelated conformations varies from one diastereoisomer to another of a single molecule. The diastereoisomers of hydroxylated acetals have permitted the recognition of the result of a competition between two hydroxyl groups for the same proton accepting site. Discussion of these experimental results in terms of glucosidic chelations have led to the hypothesis that the chelations are[Formula: see text] in cellobiose, in methyl β-cellobioside and in cellulose, respectively. We have confirmed the chelation [Formula: see text] in the case of maltose, methyl β-maltoside and amylose and it seems reasonable to suggest that a chelation [Formula: see text], can exist in these α-1,4-glucosides.[Journal translation]

scholarly journals THE USE OF INFRARED SPECTROPHOTOMETRY FOR THE ESTIMATION OF SMALL QUANTITIES OF SOME HALOGENATED HYDROCARBONS

1953 ◽  
Vol 31 (4) ◽  
pp. 328-337 ◽  
Author(s):  
L. Breitman ◽  
E. W. R. Steacie
Keyword(s):  
Quantitative Analysis ◽  
Carbon Tetrachloride ◽  
Gas Phase ◽  
Infrared Spectra ◽  
Methyl Chloride ◽  
Ternary Mixtures ◽  
Halogenated Hydrocarbons ◽  
Infrared Spectrophotometry ◽  
Absorption Bands ◽  
Binary And Ternary Mixtures

The infrared spectra of chloral, carbon tetrachloride, and chloroform have been determined between 1500 and 650 cm.−1 over a range of pressures in the gas phase. Absorption bands suitable for the quantitative analysis of binary and ternary mixtures of the components have been selected and their peak intensities shown to obey Beer's Law over the range of pressures studied. Ternary mixtures have been analyzed from the spectra with an accuracy of about 20%.The spectra of dichloromethane and methyl chloride have also been measured under comparable conditions.

The statistical thermodynamics of solutions of non-spherical molecules. I. The thermodynamic functions

1955 ◽  
Vol 229 (1177) ◽  
pp. 271-280 ◽  
Keyword(s):  
Carbon Tetrachloride ◽  
Equation Of State ◽  
Thermodynamic Functions ◽  
Statistical Thermodynamics ◽  
Intermolecular Forces ◽  
Pure Component ◽  
Experimental Results ◽  
Thermodynamics Of Solutions ◽  
Theory And Experiment

The perturbation treatment of the orientational forces between non-spherical molecules proposed by Cook & Rowlinson (1953) is extended to mixtures by using the theory of solutions put forward by Longuet-Higgins (1951). The thermodynamic functions and the equation of state of such mixtures are expressed in terms of the intermolecular forces and the properties of one pure component. Expressions are derived for the excess (or non-ideal) thermodynamic functions which are compared with the experimental results on the four solutions, benzene+ cyclohexane , benzene+carbon tetrachloride, benzene + ethylene dychloride, and cyclohexane + carbon tetrachloride. The agreement between theory and experiment is improved by taking account of the orientational forces.

Infrared spectra of aqueous sodium benzoates and salicylates in the carboxyl-stretching region: chelation in aqueous sodium salicylates

1969 ◽  
Vol 47 (24) ◽  
pp. 4577-4588 ◽  
Author(s):  
G. E. Dunn ◽  
R. S. McDonald
Keyword(s):  
Salicylic Acid ◽  
Carbon Tetrachloride ◽  
Infrared Spectra ◽  
Aromatic Compounds ◽  
Deuterium Oxide ◽  
Substituent Effects ◽  
Good Evidence ◽  
Frequency Region ◽  
Aqueous Sodium ◽  
Substituent Constants

Infrared spectra in the frequency region 1300–1760 cm−1 are reported for 41 substituted sodium benzoates and 10 substituted sodium salicylates in deuterium oxide solution, and for 9 substituted salicylic acids in chloroform and carbon tetrachloride solutions. Carboxylate stretching frequencies of benzoates and salicylates correlate poorly with substituent constants, but the asymmetric frequencies of benzoates and salicylates correlate well with each other, and the asymmetric frequencies of benzoates correlate well with the asymmetric frequencies of the corresponding nitrobenzenes. It is suggested that, among substituted aromatic compounds, group vibrations which couple with the ring vibrations may correlate well with similar vibrations of other groups, but not with coupled vibrations of different symmetry, uncoupled vibrations, or substituent constants. Chelation in chloroform solutions of salicylic acid dimers can be detected by its influence on substituent effects, but infrared spectra provide no good evidence for chelation in aqueous sodium salicylates.

Pyrrole Studies. I. The Infrared Spectra of 2-Monosubstituted Pyrroles

1963 ◽  
Vol 16 (1) ◽  
pp. 93 ◽  
Author(s):  
RA Jones
Keyword(s):  
Infrared Spectra ◽  
Infrared Absorption ◽  
Absorption Bands ◽  
Infrared Absorption Bands

The positions and intensities of the characteristic infrared absorption bands of the nucleus are recorded and discussed for thirty-five 2-monosubstituted pyrroles.

Single-molecule insight into Wurtz reactions on metal surfaces

2016 ◽  
Vol 18 (4) ◽  
pp. 2730-2735 ◽  
Author(s):  
Qiang Sun ◽  
Liangliang Cai ◽  
Yuanqi Ding ◽  
Honghong Ma ◽  
Chunxue Yuan ◽  
...  
Keyword(s):  
Single Molecule ◽  
Systematic Study ◽  
Metal Surfaces ◽  
Insight Into

We have performed a systematic study of Wurtz reactions on different metal surfaces and compared their different activities.

scholarly journals Synthesis and biotical activity of bacterial cellulose 6-(2-phthalimidoethanesulfonate)

2020 ◽  
Vol 61 (2) ◽  
pp. 29-36
Author(s):  
Zoya P. Belousova ◽  
Keyword(s):  
Bacterial Cellulose ◽  
Side Reaction ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Cellulose Derivatives ◽  
Wound Surface ◽  
Reaction Products ◽  
Absorption Bands ◽  
Hydroxymethyl Group ◽  
Antibacterial And Antifungal

Bacterial cellulose obtained by culturing Gluconacetobacter sucrofermentans in HS environment was converted to sulfonate derivatives using methane-, toluene- and 2-phthalimidoethanesulfonic acids in pyridine. When the ratio of the starting reagents is 1 : 1, the modification of bacterial cellulose according to the primary hydroxyl group of glucopyranose fragments is most likely. The formation of 6-substituted bacterial cellulose derivatives was observed in the reaction mixture. The IR spectra of the reaction products contain absorption bands, which are specific for (O–SO2) group in the region 1377-1338 cm−1 (as), 1178-1154 cm−1 (s), fragments of the corresponding sulfonic acids, as well as free hydroxyl groups of glucopyranose in the region 3495-3382 cm−1. Bacterial cellulose 2-phthalimidoethanesulfonate was dissolved in pyridine. After drying with a desiccant in a desiccator, it turned into a dense transparent film of brown color. The increased molecular film allows to explain the side reaction occurring between the oxo group and fragments of one of the chains of modified cellulose and the non-substituted hydroxymethyl group. The IR spectrum of bacterial cellulose 6-(2-phthalimidoethanesulfonate) contains absorption bands in the region 1711 cm−1, which are specific for (Ar–CO–O) group, and absorption bands in the region 1618 cm−1, which prove the presence of (CO–NH) group. In order to impart antibiotic properties to the bacterial cellulose 6-(2-phthalimido-ethanesulfonate) film, it was physically modified with clotrimazole. The obtained experimental data showed that the films subjected to treatment with a 1% solution of clotrimazole have antibacterial and antifungal effects and prevent the growth of pathogenic microbiota on the wound surface. The exit rates of clotrimazole from the bacterial cellulose 6-(2-phthalimidoethanesulfonate) film and from the pure bacterial cellulose film differed, but only slightly. 2-Phthalimidoethanesulfonate bacterial cellulose films can be used to form composites of effective wound covering, since in addition to the unique properties of bacterial cellulose itself (low allergenicity and adhesion to the wound surface, high hygroscopicity) they will have a regenerating effect.

scholarly journals OLIGOMERIC SILSESQUIOXANES COMBINING AZO- AND FLUORESCENT DYES IN ORGANIC SHELL

2019 ◽  
Vol 85 (4) ◽  
pp. 71-80
Author(s):  
Mariana Gumenna ◽  
Nina Klimenko ◽  
Alexandr Stryutsky ◽  
Alexandr Shevchuk ◽  
Viktor Kravchenko ◽  
...  
Keyword(s):  
Absorption Band ◽  
Rhodamine B ◽  
Fluorescent Dyes ◽  
Hydroxyl Groups ◽  
Uv Spectrum ◽  
Absorption Bands ◽  
Organic Shell ◽  
Similar Band ◽  
Inorganic Nanocomposites ◽  
Epoxy Groups

A method for the synthesis of reactive oligomeric silsesquioxanes, combining fragments of azo dye 4-(phenylazo)phenol and fluorescent dye Rhodamine B in various proportions in an organic shell was developed. These compounds were obtained by the reaction between the oligosilsesquioxane nanoparticles consisting of a mixture of linear, branched, ladder and polyhedral structures with epoxy groups in an organic frame (OSS–Ep) and the dyes. The structure of the synthesized substances was characterized by the methods of IR and 1H NMR spectroscopy. The UV-Vis spectra of OSS–Pp–Rh in DMF solution contain absorption bands characteristic of both acidic (560 and 350 nm) and lactone (in the range of 318–326 nm) forms of Rhodamine B. The absorption band of 4-(phenylazo) phenol fragments corresponding to π−π* transition is observed at 348 nm and overlaps the absorption band of Rhodamine B at 350 nm.The intensity of the absorption bands of fragments of various dyes depends on their content in organic frame of the silsesquioxane core. The intensity of the absorption bands at 348 nm and at 560 nm increases with an increase in the content of 4-(phenylazo)phenol and Rhodamine B correspondingly.It should be noted that when using DMF as a solvent the absorption band corresponding to acidic form of Rhodamine B at 560 nm in the UV-Vis spectra of the compounds obtained is more intense than similar band in the spectrum of the original Rhodamine B. Therefore, the attachment of Rhodamine B to the silsesquioxane core of oligomeric silsesquioxanes mixture does not have a significant effect on the position of absorption maxima in the UV-spectrum and prevents dye’s fragments from converting to the colorless lactone form. In the fluorescence spectra of OSS–Pp–Rh obtained using DMF as a solvent a peak at λ max = 592 nm (λex= 520 nm) is observed. The position of the fluorescence peak and its intensity in the spectra at the same optical density of the medium practically do not depend on the ratio of fragments of 4-(phenylazo)phenol and Rhodamine B in organic frame of OSS–Pp–Rh.  The combination of two different chromophores in organic shell of the silsesquioxane core broadens the range of absorbed light and the change of their ratio allows to adjust the absorption intensity in a certain area. The presence of hydroxyl groups makes it possible to introduce the obtained compounds into the composition of polymeric organic-inorganic nanocomposites by covalent bonding.

A Systematic Study of Turbulent Film Flow

1974 ◽  
Vol 96 (1) ◽  
pp. 118-126 ◽  
Author(s):  
G. G. Hirs
Keyword(s):  
Systematic Study ◽  
Classification System ◽  
Film Flow ◽  
Flow Theory ◽  
Bulk Flow ◽  
Experimental Results ◽  
Flow Theories ◽  
Set Up ◽  
Flow Experiments

Turbulent film flow theories can only be verified on the basis of a large number of experimental results. Since it will be useful to handle these experimental results more or less systematically and to get some idea of the amount of work yet to be done, the first objective of this paper is to set up a classification system for turbulent film flow experiments. The second objective is to verify the bulk flow theory on the basis of the limited number of experimental results available in the literature and to show this theory to be compatible with these results.

Gaseous infrared spectra of the simplest geminal diol CH2(OH)2 and the isotopic analogues in the hydration of formaldehyde

2021 ◽  
Author(s):  
Hung-Yang Jain ◽  
Chih-Tsun Yang ◽  
Li-Kang Chu
Keyword(s):  
Infrared Spectrum ◽  
Infrared Spectra ◽  
Absorption Bands ◽  
Geminal Diol

The infrared spectrum of the simplest geminal diol, methanediol or methylene glycol (CH2(OH)2), was successfully probed in the gaseous hydration of formaldehyde. The observed absorption bands coincided with the anharmonic...

Sign in / Sign up

Export Citation Format

Share Document