Investigation of hydrogen bonding in ?-aminonicotine by the method of comparing infrared absorption spectra

1956 ◽  
Vol 5 (3) ◽  
pp. 323-326
Author(s):  
Ya. L. Goldfarb ◽  
M. S. Kondakova ◽  
D. N. Shigoria
Keyword(s):  
Hydrogen Bonding ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Infrared Absorption Spectra

Infrared Absorption Spectra of Some Hydroxy Compounds in the 3 Micron Region

1961 ◽  
Vol 14 (2) ◽  
pp. 211 ◽  
Author(s):  
JS Cook ◽  
IH Reece
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Carbon Tetrachloride ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Butyl Phenol ◽  
Infrared Absorption Spectra ◽  
Sterically Hindered ◽  
Hydroxy Compounds

Infrared absorption spectra are reported in the region 2.6 to 3.8 microns for the solid state and for solutions in carbon tetrachloride of 10 sterically hindered hydroxy compounds. Absorption types vary from that of 2,4,6-tri-t-butyl phenol, where the OH group is completely " free " in both states, to that of 3,5-diaceto-p-cresol where the bands are diffuse and are centred about 3.4 microns corresponding to very strong hydrogen bonding. Deuteration studies suggest that splitting of the free OH band in several cases may arise from azimuthal orientations of the OH group and for tri-cyclohexyl carbinol -ΔH for this equilibrium has been estimated at 1 kcal/g-mole.

Characteristic Infrared Absorption Spectra and Frequencies of Carbamate Pesticides

1966 ◽  
Vol 49 (2) ◽  
pp. 412-452
Author(s):  
Jo-Yun T Chen ◽  
Walter R Benson
Keyword(s):  
Hydrogen Bonding ◽  
Liquid Phase ◽  
Absorption Spectra ◽  
Infrared Spectra ◽  
Infrared Absorption ◽  
Model Compounds ◽  
Carbamate Pesticides ◽  
Infrared Absorption Spectra ◽  
Carbonyl Absorption ◽  
Absorption Frequencies

Abstract The infrared spectra of 32 carbamate pesticides and model compounds in liquid (CS2) and solid (KBr) phases are presented. The characteristic infrared absorption frequencies and associated structures are tabulated in a summary and presented in a correlation chart. The carbonyl absorption frequencies of carbamates containing the N—H group are shifted to higher frequencies by approximately 35 cm-1 in going from the solid to the liquid phase. This shift is attributed to a loss of hydrogen bonding. In general the N,N-disubstituted carbamates show no such shift.

Spectroscopic Studies on Vapour Phase Tautomerism of Natural Bases Found in Nucleic Acids

1978 ◽  
Vol 33 (11-12) ◽  
pp. 876-883 ◽  
Author(s):  
Maciej J. Nowak ◽  
Krystyna Szczepaniak ◽  
Andrzej Barski ◽  
David Shugar
Keyword(s):  
Hydrogen Bonding ◽  
Nucleic Acids ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Equilibrium Constants ◽  
Vapour Phase ◽  
Induced Mutations ◽  
Infrared Absorption Spectra ◽  
Substituted Uracils

Infrared absorption spectra, in the vapour phase, have been recorded in the regions of NH, OH and carbonyl stretching frequencies, for a series of 1-substituted uracils and 9-substituted adenine and hypoxanthine, formal analogues of the natural nucleosides of uracil, adenine and hypoxanthine found in DNA and/or RNA. A number of related analogues was also examined, including the N-methyl derivatives of the known mutagen and chemotherapeutic agent, 5-fluorouracil. The infrared absorption spectra provide unequivocal evidence for the existence of 1-substituted uracils as the 2,4-diketo tautomer, of 9-substituted hypoxanthine as the 6-keto tautomer, and of 9-substituted adenine as the 6-amino tautomer. These are the known predominant tautomeric forms in solution, so that the gas phase results are in sharp contrast with those for other nitrogen heterocycles, where the tautomeric equilibrium constants may differ by several orders of magnitude in going from solution to the vapour phase. The significance of these results is evaluated in relation to the types of heterocyclic bases found in natural nucleic acids, and to concepts of spontaneous and induced mutations in terms of mis-pairing. The ultraviolet absorption spectra of the various compounds have also been examined in the gas phase, but proved of relatively limited use in studies on tautomeric equilibria under these conditions. Heats of vaporization have been determined for most of the compounds examined. In particular the heat of vaporization for 1,3-dimethyluracil, which is incapable of association by hydrogen bonding in the condensed phase, is much lower than for uracil and 1 (3) -methyluracils which can associate by hydrogen bonding.

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