A Low Temperature Infrared Study on the Association of Thiols with Organic Oxygen Bases

1974 ◽  
Vol 52 (5) ◽  
pp. 738-743 ◽  
Author(s):  
R. Bicca De Alencastro
Keyword(s):  
Low Temperature ◽  
Infrared Spectra ◽  
Infrared Study ◽  
Text Type ◽  
Organic Bases

The infrared spectra of mixtures of propane-1-thiol and several oxygen-containing weak organic bases have been measured between 2500 and 2650 cm−1, in a 1:1 mixture of CCl3F and C2F4Br2 at temperatures ranging from 20 to –190 °C. Association of the [Formula: see text] type was observed between propane-1-thiol and 2-methyl-tetrahydrofuran, or cyclopentanone. This association is less important between the thiol and hexachloropropanone. In the case of a thiol–furan mixture association of the [Formula: see text] type is strongly indicated.

A Low Temperature Infrared Study of Self-association in Thiols

1972 ◽  
Vol 50 (22) ◽  
pp. 3594-3600 ◽  
Author(s):  
R. Bicca de Alencastro ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Low Temperatures ◽  
Infrared Study ◽  
Text Type ◽  
Stretching Vibration ◽  
Aliphatic Thiols ◽  
Self Association ◽  
Associated Species

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.

scholarly journals Low-temperature infrared study of ammonium carbamate formation

1984 ◽  
Vol 62 (5) ◽  
pp. 945-948 ◽  
Author(s):  
C. Hisatsune
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Low Temperatures ◽  
Hydrogen Ion ◽  
Ion Transfer ◽  
Infrared Study ◽  
Ammonium Carbamate

Two types of infrared spectra observed during the formation of ammonium carbamate [Formula: see text] from the reaction of NH3 and CO2 in the solid state at low temperatures have been re-examined. These spectra had been assigned previously to amorphous and crystalline ammonium carbamate but the present data suggest their origins to be [Formula: see text] and its unstable precursor (NH3)2CO2 in which CO2 is bent. Spectra of amorphous and crystalline ammonium carbamate have been distinguished by comparing the systems NH3/CO2 and NH3/CO2/H2O. Hydrogen ion transfer in the diammoniates occurred at about −80 °C for NH3/CO2 and about −40 °C for ND3/CO2.

An infrared study of the photoisomerization of N-benzylideneaniline

1982 ◽  
Vol 60 (13) ◽  
pp. 1720-1726 ◽  
Author(s):  
J. W. Lewis ◽  
C. Sandorfy
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Infrared Spectra ◽  
Polycrystalline Films ◽  
Infrared Study ◽  
Spectral Changes ◽  
Thin Polycrystalline

The infrared spectra of Nujol solutions and thin polycrystalline films of N-benzylideneaniline have been investigated. The 313 nm irradiation of ambient temperature samples produces no observable changes in the infrared spectra, however, similar irradiation of samples maintained at 77 K results in spectral changes that are thermally and photochemically reversible. The infrared spectra of low temperature irradiated samples are interpreted in terms of trans → cis photoisomerization.

A Low Temperature Infrared Study of Hydrogen Bonding in N-Alkylacetamides

1973 ◽  
Vol 51 (21) ◽  
pp. 3640-3646 ◽  
Author(s):  
Marie-Claude Bernard-Houplain ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Bond Formation ◽  
Coupling Constant ◽  
Infrared Study ◽  
Hydrogen Bond Formation ◽  
Stretching Vibration ◽  
Secondary Amides

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.

A Low-temperature Infrared Study of Self-association in Thiolic Acids

1973 ◽  
Vol 51 (9) ◽  
pp. 1443-1447 ◽  
Author(s):  
R. Bicca de Alencastro ◽  
C. Sandorfy
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Carbonyl Groups ◽  
Infrared Study ◽  
Text Type ◽  
Stretching Vibration ◽  
Self Association ◽  
High Concentrations ◽  
Associated Species ◽  
Anharmonicity Constants

The i.r. spectra of thioloacetic and thiolobenzoic acids were measured in both the fundamental and first overtone regions of the S—H stretching vibration, in a mixture of CCl3F and C2F4Br2, at temperatures ranging from 20 to −190 °C. [Formula: see text] type bonds are formed at low temperatures or at high concentrations of solute. Two different species can be detected. The first is probably an open dimer and the second a cyclic dimer. The S—H anharmonicity constants are of the order of 50–60 cm−1, for both free and associated species, and have about the same value as in aliphatic or aromatic mercaptans. Carbonyl groups have lower anharmonicities. Their value is about 10 cm−1, for both free and associated species.

Infrared spectra of carbon monoxide chemisorbed on iron at low temperature

1972 ◽  
Vol 76 (22) ◽  
pp. 3180-3184 ◽  
Author(s):  
G. Blyholder ◽  
Masako Tanaka
Keyword(s):  
Carbon Monoxide ◽  
Low Temperature ◽  
Infrared Spectra

Infrared spectra of the ammonium ion in crystals. Part VIII. Spectroscopic criteria of highly-bent hydrogen bonds

1980 ◽  
Vol 58 (9) ◽  
pp. 867-874 ◽  
Author(s):  
Osvald Knop ◽  
Wolfgang J. Westerhaus ◽  
Michael Falk
Keyword(s):  
Low Temperature ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Ammonium Ion ◽  
Temperature Transition ◽  
Increasing Temperature

Available evidence suggests that (1) the stretching frequencies of highly-bent hydrogen bonds decrease with increasing temperature, regardless of whether the bonds are static or dynamic in character, to a single acceptor or to several competing acceptors; and (2) departures from symmetric trifurcation (or bifurcation) toward asymmetric situations lower the stretching frequency. In further support of these criteria isotopic probe ion spectra between 10 K and room temperature have been obtained for taurine and for trigonal (NH4)2MF6 (M = Si, Ge, Sn, Ti). Evidence of a low-temperature transition at 100(10) K in trigonal (NH4)2SnF6 is presented, and existence of the previously reported transition at 38.6 K in trigonal (NH4)2SiF6 is confirmed. Symmetry changes associated with these transitions are discussed.

Low-temperature far-infrared study of localized states in In-doped Pb0.75Sn0.25Te single crystals

1992 ◽  
Vol 4 (17) ◽  
pp. 4323-4330 ◽  
Author(s):  
N Romcevic ◽  
Z V Popovic ◽  
D R Khokhlov
Keyword(s):  
Low Temperature ◽  
Single Crystals ◽  
Far Infrared ◽  
Localized States ◽  
Infrared Study
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