Abstract:Monodeuterated derivatives of the salts of tyrosine, valine, glycylglycine, and glycylglycylglycine are investigated by infrared spectroscopy. Irradiation in the spectral region of the N-D stretch bands produces spectral holes and antiholes. These result from rotation of N-D-containing moieties. The holes and antiholes identify the vibrations of the amino group and provide information on the hydrogen-bonding environment. Both the various amino acid salts and the two peptide salts hole burn, suggesting that inf… Show more
“…The difference spectrum shows three bands at 2447, 2453, and 2472 cm -1 . These N−D stretching bands occur at considerably higher frequencies than the N−D bands seen in the other ammonium ion systems we have investigated. − 3 Infrared spectra for the MOM complex at 20 K. The middle spectrum is of the complex with 2% deuterium and the lower spectrum is of the nondeuterated complex. The upper spectrum is the difference spectrum after the nondeuterated spectrum has been subtracted from the 2% deuterated spectrum.…”
Section: Resultsmentioning
confidence: 89%
“…These N-D stretching bands occur at considerably higher frequencies than the N-D bands seen in the other ammonium ion systems we have investigated. [2][3][4] The peak at 2472 cm -1 was initially chosen for hole burning since it is clearly separated from the other two peaks. At 20 K, irradiation at this wavenumber produced a hole at 2472 cm -1 and a broad antihole at 2450 cm -1 .…”
The N-D stretching region in the infrared spectrum of the ammonia complex of tris-(2-methoxymethyl-phenol)-borane containing one D atom has been examined. The N-D bands have been hole burned, and the resulting spectra reveal the reorientation kinetics of the ammonia. The ammonia is hydrogen bonded with the bond distances and reorientation barrier typical of other compounds. The N-D stretching frequencies are higher than those of comparison compounds.
“…The difference spectrum shows three bands at 2447, 2453, and 2472 cm -1 . These N−D stretching bands occur at considerably higher frequencies than the N−D bands seen in the other ammonium ion systems we have investigated. − 3 Infrared spectra for the MOM complex at 20 K. The middle spectrum is of the complex with 2% deuterium and the lower spectrum is of the nondeuterated complex. The upper spectrum is the difference spectrum after the nondeuterated spectrum has been subtracted from the 2% deuterated spectrum.…”
Section: Resultsmentioning
confidence: 89%
“…These N-D stretching bands occur at considerably higher frequencies than the N-D bands seen in the other ammonium ion systems we have investigated. [2][3][4] The peak at 2472 cm -1 was initially chosen for hole burning since it is clearly separated from the other two peaks. At 20 K, irradiation at this wavenumber produced a hole at 2472 cm -1 and a broad antihole at 2450 cm -1 .…”
The N-D stretching region in the infrared spectrum of the ammonia complex of tris-(2-methoxymethyl-phenol)-borane containing one D atom has been examined. The N-D bands have been hole burned, and the resulting spectra reveal the reorientation kinetics of the ammonia. The ammonia is hydrogen bonded with the bond distances and reorientation barrier typical of other compounds. The N-D stretching frequencies are higher than those of comparison compounds.
“…These studies used distinct patterns of holes and anti-holes to suggest different amino acid conformations and hydrogen bonding parameters. 101 Two other phenomena, satellite holes and non-resonant holes, can also appear in hole-burning spectra. 93 Non-resonant holes form at the frequency of vibronic bands that are associated with the burnt electronic transition if it resides in the inhomogeneous line width.…”
Section: Hole-burning Mechanismsmentioning
confidence: 99%
“…These studies used distinct patterns of holes and anti-holes to suggest different amino acid conformations and hydrogen bonding parameters. 101…”
Hole-burning spectroscopy, a high-resolution spectroscopic technique, allows details of heterogeneous nano-environments in biological systems to be obtained from broad absorption bands. Recently, this technique has been applied to proteins, nucleic acids, cells, and substructures of water to probe the electrostatic conditions created by macromolecules and the surrounding solvent. Starting with the factors that obscure the homogeneous linewidth of a chromophore within an inhomogeneously broadened absorption or emission band, we describe properties and processes in biological systems that are reflected in the measured hole spectra. The technique also lends itself to the resolution of perturbation experiments, such as temperature cycling to elucidate energy landscape barriers, applied external electric fields (Stark effect) to measure net internal electric fields, and applied hydrostatic pressure to find the volume compressibility of proteins.
“…Sodium sulfanilate dihydrate, NH 2 C 6 H 4 SO 3 Na·2H 2 O (SSDH), forms a crystalline hydrate with a number of interesting features suitable for elucidating conformational dynamics. Infrared studies using deuterium substitution, the change of the spectrum with temperature, and infrared hole burning have revealed the dynamics of the amino group of amino acid salts and of the water of hydration in a number of different compounds , in the crystal. Similarly, irradiation of NH-containing compounds using a combination of ultraviolet and infrared radiation has produced observable conformational changes in molecules embedded in gas-phase clusters. , …”
We have studied the infrared spectra of the OH(D) hydrogen bonds from the water and NH(D) bonds
from the NH2 group in the title compound as functions of deuterium concentration and temperature. Some of
the vibrational stretching bands are re-assigned. The crystal contains two distinct water molecules. The two
OD bands from one HOD molecule merge together as the temperature is raised, suggesting homogenization
of the environments of two OD's due to increasing librational motion. The two OD bands from the other
HOD molecule behave as expected and do not merge over the temperature range. The two ND bands of the
HND group show the overlap or resonances between the ND bands and combination bands. The shifts with
temperature of the various stretching bands of the hydrogen-bonded atoms are in agreement with the changes
expected from the changes in structure determined by previous X-ray analyses.
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