scholarly journals Low temperature infrared spectra of polyglycines and C?H ? O?C hydrogen bonding in polyglycine II

Biopolymers ◽  
1968 ◽  
Vol 6 (3) ◽  
pp. 401-407 ◽  
Author(s):  
S. Krimm ◽  
K. Kuroiwa
1983 ◽  
Vol 61 (9) ◽  
pp. 2077-2088 ◽  
Author(s):  
Theresa Huston ◽  
I. C. Hisatsune ◽  
Julian Heicklen

Low-temperature infrared spectroscopy has been used to examine the systems NH3 + H2O, NH3 + HCl, H2O + HCl, NH3 + HNO3, and NH2OH + HNO3. Hydrogen-bonding in the solid states greatly reduces the reactivities in these systems. Temperatures where reactions initiated in the systems NH3(s) + HCl(g), HNO3(s) + NH3(g), H2O(s) + HCl(g), and NH2OH(s) + HNO3(s) were, respectively, −145, −130, −127, and −125 °C. Infrared spectra of 2NH3•H2O, NH3•H2O, NH4Cl•3NH3, NH4NO3•3NH3, NH4NO3•2HNO3, NH2OH2+NO3−, NH3OH+NO3−, H3O+Cl−, H5O2+Cl−, and H5O2+Cl−•H2O have been identified in these reaction systems.


1972 ◽  
Vol 50 (22) ◽  
pp. 3594-3600 ◽  
Author(s):  
R. Bicca de Alencastro ◽  
C. Sandorfy

The infrared spectra of several aliphatic thiols and of benzenethiol were measured between 2400 and 2700 cm−1, and 4800 and 5300 cm−1 in a 1:1 mixture of CCl3F and C2F4Br2, at temperatures ranging from 20 to −190 °C. Dimerization takes place at low temperatures and more highly associated species also appear. Free S—H groups are present in the solutions as well as in the pure liquids, even at the lowest temperatures. The association is of the [Formula: see text] type in aliphatic thiols; both [Formula: see text] and [Formula: see text] bonds are found in the case of benzenethiol and α-toluenethiol. Hydrogen bonding has little effect on the anharmonicity of the S—H stretching vibration.


1985 ◽  
Vol 63 (12) ◽  
pp. 3328-3353 ◽  
Author(s):  
Osvald Knop ◽  
Wolfgang J. Westerhaus ◽  
Michael Falk ◽  
Werner Massa

The ir spectra of the isotopic probe ion NH3D+ have been used to obtain information about the symmetry, orientation, and hydrogen-bonding involvement of the ammonium ion, between 10 K and room temperature, in NH4F, NH4HF2, (NH4)2[Cr(H2O)6]F5, NH4PF6, (NH4)3SiF7, the elpasolites (NH4)2BFeF6 (B = Na, K) and CS2NH4MF6 (M = Fe, Al), and the cryolites (NH4)3MF6 (M = Al, Cr, Fe). Several of these fluorides exhibit low-temperature transitions, some of which are evident in the probe-ion spectra. It is shown that relating the isotopically isolated ND stretching and bending frequencies to the [Formula: see text] distances and to the coordination numbers of the ammonium ion reveals important trends in the dependence of the behaviour of the ion on its immediate environment in the crystal. A detailed discussion is presented of the effect of ionic size and the geometric tolerance factor t on the transition temperatures of cubic cryolite, perovskite, and elpasolite halides, as well as on the anisotropy of the principal thermal amplitudes of the halogen atom in such compounds. The relation between Ttr and the frequency of the ND stretching absorption of NH3D+ in the ammonium representatives of these classes of halides is also explored.


2006 ◽  
Vol 41 (1) ◽  
pp. 73-82 ◽  
Author(s):  
S. Jarmelo ◽  
I. Reva ◽  
M. Rozenberg ◽  
P.R. Carey ◽  
R. Fausto

1991 ◽  
Vol 69 (10) ◽  
pp. 1520-1527 ◽  
Author(s):  
Louise Schriver ◽  
André Schriver ◽  
Stefan Peil ◽  
Otto Schrems

Infrared spectra are reported for binary complexes between perfluoro-tert-butanol as proton donor and nitromethane and acetone as bases. The complexes have been investigated in low temperature solutions and in cryogenic matrices. The spectra have been evaluated in terms of frequency shifts (ΔVOH), half widths (FWHH) and anharmonicities (κ) caused by the hydrogen bonding of these complexes. The influence of the environment (solvents and solid matrices) as well as temperature on the spectra of the complexes has also been studied and is discussed in detail. Key words: hydrogen bonding, temperature effects, solutions, matrix.


1973 ◽  
Vol 51 (21) ◽  
pp. 3640-3646 ◽  
Author(s):  
Marie-Claude Bernard-Houplain ◽  
C. Sandorfy

The infrared spectra of N-methylacetamide and two other secondary amides were measured in solution at temperatures ranging from 22 to −190 °C in both the fundamental and the overtone regions. At least two hydrogen bonded species are found as association increases with decreasing temperature. The effect of hydrogen bond formation on the anharmonicity of the NH stretching vibration and on the NH stretching – NH bending coupling constant is examined.


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