Solvent effects on infrared frequencies—II

The dilute solution properties of 4-phenyl-1,2,4-triazoline-3,5-dione-modified polybutadienes were studied in tetrahydrofuran by static and dynamic light scattering and compared with those from unmodified polybutadiene chains. For the unmodified polymer, the scaling laws were established and the coil interpenetration parameter kf, was determined in the thermodynamically good solvent tetrahydrofuran; the chains exhibited common flexible chain behavior. For the modified polybutadiene, the results indicate at infinite dilution a weak extent of intermolecular crosslinking via the urazole groups, coupled with a very high extent of intramolecular ring formation. In order to evaluate the fraction of rings, an analysis of the association equilibrium by Fourier-transform infrared spectroscopy (FTIR) was performed in the absorption region of the carbonyl stretching vibration of the urazole ring.

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“…ae,=a(l -r ) (30) with r the fraction of rings. In this work it was possible to determine the fraction of rings as follows.…”

Section: Mwmentioning

confidence: 99%

Dilute solution properties of polybutadiene modified by 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione

Bica

Burchard

Stadler

1996

Macro Chemistry & Physics

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“…Acetone-chloroform mixtures constitute an interesting mixed liquid that attracted a rather large number of investigation in the past using both experimental [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and theoretical [18][19][20] methods. Many of these studies have looked at the ideality of these mixtures as originally defined by Raoult's law for vapor pressures [21] or its generalizations to other properties of liquid mixtures.…”

Section: Introductionmentioning

confidence: 99%

“…The observed nonideal behavior of this system has generally been attributed to formation of hydrogen bonded complexes between unlike molecules. A number of spectral studies [7][8][9][10][11][12][13][14][15] provided evidence for hydrogen bond formation between carbonyl oxygen of acetone and a hydrogen atom of chloroform molecule. Since acetone and chloroform are miscible at all proportions, they are largely used as an important solvent medium in various chemical processes and also as azeotropic mixtures [2][3][4][5]11,22].…”

Section: Introductionmentioning

confidence: 99%

Structural, single-particle and pair dynamical properties of acetone–chloroform mixtures with dissolved solutes

Gupta

Chandra

2011

Chemical Physics

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“…Such weak hydrogen bonds, especially those of haloforms, have been examined with the help of different techniques: Nuclear magnetic resonance (Lichter and Roberts, 1970;Lin and Tsay, 1970;Korinek and Schneider, 1957;Wiley and Miller, 1972), infrared spectroscopy (Lascombe, Devanie, and Josien, 1964;Whetsel and Kagarise, 1962), freezing point diagrams (Korinek and Schneider, 1957), calorimetry (Findlay, Keniry, Kidman and Pickles, 1967;Tamres, t952), and X-ray crystallography (Dahl and Hassel, t970;Hassel, 1970). These results indicate stoichiometric complexes due to hydrogen bonding of aliphatic hydrogen atoms with lone-pair electrons and aromatic systems.…”

Section: Introductionmentioning

confidence: 99%

Stereospecificity of the genetic code

Melcher

1974

J Mol Evol

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Summary.A sterical correlation of the amino acids to their anticodon nucleotides is given. The main principle is the intercalation of the amino acid and the binding of the aliphatic amino acid hydrogen atoms through hydrogen bonds to the a-electrons of the bases. The amino groups of the bases and the ribose phosphate chain are additional binding sites for the amino acid. The strength of these hydrogen-a bonds is considerably increased by the protonation of the carboxyl group of the amino acid. Such a protonation occurs in esterification processes and gives in these reactions the possibility of an activated complex where the proposed complementarity is also energetically favoured. Evolutionary considerations show an uncomplicated way from the chemical reactions of prebiologically formed organic molecules to a living system.

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Solvent effects on infrared frequencies—II

Cited by 67 publications

References 19 publications

Dilute solution properties of polybutadiene modified by 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione

Dilute solution properties of polybutadiene modified by 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione

Structural, single-particle and pair dynamical properties of acetone–chloroform mixtures with dissolved solutes

Stereospecificity of the genetic code

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