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 Fourier transform infrared study of the electrophilic attack at the N7-site of guanosine-5′-monophosphate

1984 ◽  
Vol 62 (2) ◽  
pp. 266-272 ◽  
Author(s):  
H. A. Tajmir-Riahi ◽  
T. Theophanides
Keyword(s):  
Fourier Transform ◽  
Infrared Spectra ◽  
Fourier Transform Infrared ◽  
Divalent Metal ◽  
Ring System ◽  
Disodium Salt ◽  
Divalent Metal Ions ◽  
Electrophilic Attack ◽  
Infrared Study ◽  
Spectral Changes

Fourier transform infrared spectra of several N7-bound cations of guanosine-5′monophosphate disodium salt (5′-GMPNa2), such as N7-H+GMP, N7-MeGMP, and N7-MGMP, where Me = CH3+ and M = divalent metal ions, Cd, Mn, Co, Ni, Cu, Pt, and Mg, have been recorded and a correlation between the spectral changes and the nature of the electrophile (H+, CH3+, and M2+) bound has been established. Spectroscopic evidence shows that methylation of the N7-position of 5′-GMPNa2 causes larger perturbation on the guanine ring system than protonation or metalation, in the order Me+ > H+ > M2+. The effect of an N7-electrophilic attack on the vibrational frequencies of the purine, the sugar, and the phosphate group is discussed.

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.

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.

POSSIBLE STRUCTURAL PHASE TRANSITION OF SINGLE PHASE (Bi, Pb)2Sr2Ca2Cu3O10+y SUPERCONDUCTING CERAMIC: AN INFRARED STUDY

1990 ◽  
Vol 04 (14) ◽  
pp. 905-911
Author(s):  
HE AISHENG ◽  
ZHANG JINCANG ◽  
CHANG FANGGAO ◽  
LU WEIQIN ◽  
XIANG JIONG ◽  
...  
Keyword(s):  
Phase Transition ◽  
Ambient Temperature ◽  
Structural Phase Transition ◽  
Infrared Spectra ◽  
Single Phase ◽  
Structural Phase ◽  
Vibrational Modes ◽  
Infrared Study ◽  
Lattice Constants ◽  
Superconducting Ceramic

The infrared spectra of single phase (Bi, Pb)2Sr2Ca2Cu3O 10+y polycrystalline samp were studied over a temperature range of 300–120 K. Three vibrational modes were found at ambient temperature. A new band appears at 900 cm −1 near 200 K and experi evidence proved that the appearance of the new band is actually through an isothermal-like process, indicating a structural phase transition taking place. Unstable fluctuations were also observed between 200 and 140 K. This phenomenon is consistent with our previously reported ultrasonic, specific heat and lattice constants anomalies of the same sample. A possible mechanism of this phase transition is also discussed.

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.

Identification of the Isomers of Carvomenthol by an Infrared Study of the OH-Stretching Vibration

1987 ◽  
Vol 41 (7) ◽  
pp. 1251-1253 ◽  
Author(s):  
E. T. G. Lutz ◽  
P. A. Van Der Schaaf ◽  
J. H. Van Der Maas
Keyword(s):  
Ambient Temperature ◽  
Spectral Data ◽  
Infrared Spectra ◽  
Infrared Study ◽  
Stretching Vibration ◽  
Natural Mixture

A natural mixture of carvomenthols has been separated by HPLC into its four possible isomers. The infrared spectra of the OH-stretching vibration have been recorded for each of these components as a solution in CCl4 and CS2. Identification of the isomers followed, on the basis of these spectral data and those of some reference compounds. Evidence is found for a ring-conversion equilibrium in iso-carvomenthol at ambient temperature.

A Green and Energy-efficient Photocatalytic Process for accelerated synthesis of Lactic Acid Esters using functionalized quantum dots

2021 ◽  
Author(s):  
Priyanka Verma ◽  
Ravinder Kumar Wanchoo ◽  
Amrit Pal Toor
Keyword(s):  
Quantum Dots ◽  
Lactic Acid ◽  
Low Temperature ◽  
Ambient Temperature ◽  
Energy Efficient ◽  
Photocatalytic Process ◽  
Photochemical Process ◽  
Line P ◽  
Safe Approach ◽  
Acid Esters

Sulphonate-grafted-Titania (SO3H-TiO2) quantum dot catalyzed photochemical process offered an energy-efficient, accelerated, and safe approach to synthesize lactic acid esters at ambient temperature conditions. This low-temperature route is conceived in line...

Structural features of Sm1–x Eu x S thin polycrystalline films

2017 ◽  
Vol 51 (6) ◽  
pp. 828-830 ◽  
Author(s):  
V. V. Kaminskii ◽  
S. M. Solov’ev ◽  
G. D. Khavrov ◽  
N. V. Sharenkova ◽  
Shinji Hirai
Keyword(s):  
Structural Features ◽  
Polycrystalline Films ◽  
Thin Polycrystalline
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