scholarly journals Extended timescale 2D IR probes of proteins: p-cyanoselenophenylalanine

2017 ◽  
Vol 19 (15) ◽  
pp. 10081-10086 ◽  
Author(s):  
S. Ramos ◽  
K. J. Scott ◽  
R. E. Horness ◽  
A. L. Le Sueur ◽  
M. C. Thielges
Keyword(s):  
Hydrogen Bonding ◽  
Protein Dynamics ◽  
High Sensitivity ◽  
2D Ir ◽  
Infrared Studies ◽  
Long Lifetime

The cyano vibration of cyano-seleno-phenylalanine has a long lifetime with high sensitivity to hydrogen bonding that makes it a promising new probe to advance 2D infrared studies of protein dynamics on longer timescales.

Infrared studies on rotational isomerism. III. 2-Chloro- and 2-bromo-ethanol

1969 ◽  
Vol 47 (6) ◽  
pp. 901-910 ◽  
Author(s):  
Paul Buckley ◽  
Paul A. Giguère ◽  
Michel Schneider
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Rotational Isomerism ◽  
Apparent Discrepancy ◽  
Trans Isomers ◽  
Kcal Mole ◽  
Infrared Studies ◽  
Isotopic Molecule ◽  
Intramolecular Hydrogen ◽  
Unambiguous Assignment

The relative intensities of the C—X stretching bands of the gauche and trans isomers in the vapor were measured as a function of temperature up to 165 °C for 2-chloroethanol, and up to 130 °C for 2-bromoethanol. From these the enthalpy differences between the two isomers were found to be 1.20 and 1.45 ± 0.1 kcal mole−1 respectively for the two halogenated ethanols. Similar measurements on the O—H stretching bands gave values higher than the above by 0.45 kcal mole−1 for both compounds. This apparent discrepancy is interpreted as due to a second gauche isomer, the OH group of which is not engaged in intramolecular hydrogen bonding, and which is less stable than the trans isomer.A study of the isotopic molecule ClCH2—CH2OD has led to unambiguous assignment of the OH bending and torsional frequencies. The spectra of the solid show that 2-chloroethanol can exist in two different crystalline phases: a stable one consisting of gauche molecules only, and a metastable one containing both isomers.

scholarly journals Vibrational dynamics and solvatochromism of the label SCN in various solvents and hemoglobin by time dependent IR and 2D-IR spectroscopy

2014 ◽  
Vol 16 (36) ◽  
pp. 19643-19653 ◽  
Author(s):  
Luuk J. G. W. van Wilderen ◽  
Daniela Kern-Michler ◽  
Henrike M. Müller-Werkmeister ◽  
Jens Bredenbeck
Keyword(s):  
Hydrogen Bonding ◽  
Ir Spectroscopy ◽  
Structural Dynamics ◽  
Spectral Diffusion ◽  
Time Dependent ◽  
Vibrational Dynamics ◽  
2D Ir

The vibrational label SCN is used to report on local structural dynamics in a protein revealing spectral diffusion on a picosecond scale. The SCN spectra are compared to the response of methylthiocyanate in solvents with different polarity and hydrogen-bonding capabilities.

Low-temperature infrared studies of some acid–base reactions

1983 ◽  
Vol 61 (9) ◽  
pp. 2077-2088 ◽  
Author(s):  
Theresa Huston ◽  
I. C. Hisatsune ◽  
Julian Heicklen
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Acid Base ◽  
Reaction Systems ◽  
Solid States ◽  
Infrared Studies

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.

scholarly journals Synthesis, structural chemistry and antimicrobial activity of −(−) borneol derivative

2010 ◽  
Vol 8 (5) ◽  
pp. 1127-1133 ◽  
Author(s):  
Khalid Al-Farhan ◽  
Ismail Warad ◽  
Saud Al-Resayes ◽  
Moustafa Fouda ◽  
Mohamed Ghazzali
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Hydrogen Bonding ◽  
Reference Material ◽  
High Sensitivity ◽  
Structural Determinants ◽  
Single Crystal Diffraction ◽  
Methane Sulfonate ◽  
X Ray ◽  
Hirshfeld Surfaces

AbstractBorneol is a monoterpene that is a part of traditional Chinese and Japanese medicine. (−) borneol reacted with methanesulfonyl chloride in THF/pyridine to afford the new 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methane sulfonate derivative in excellent yield. The product is characterized by H1NMR, C13NMR, mass spectroscopy as well as elemental analysis and its structure was identified by X-ray single crystal diffraction. The packing of 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methanesulfonate exhibits the non-classical C-H···O hydrogen bonding in C(4) and R22(8) chain and ring motifs as structural determinants. This was also confirmed by the analysis of Hirshfeld surfaces. The 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methane sulfonate antimicrobial activity was tested and compared with its parent (−) borneol against three different pathogens. Particularly, 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methane sulfonate showed high sensitivity, compared to Chloramphenicol reference material, against Escherichia coli.

Simulating the seasonal cycle of 13C

2020 ◽  
Author(s):  
Sebastian Lienert ◽  
Christoph Köstler ◽  
Sönke Zaehle ◽  
Fortunat Joos
Keyword(s):  
Seasonal Cycle ◽  
Atmospheric Transport ◽  
High Sensitivity ◽  
System Model ◽  
Atmospheric Measurements ◽  
Vegetation Model ◽  
Dynamic Global Vegetation Model ◽  
The Earth ◽  
Long Lifetime ◽  
Global Vegetation

<p>We investigate the seasonal cycle of δ<sup>13</sup>CO<sub>2</sub> using the Earth system model of intermediate complexity Bern3D-LPX. Using a model of atmospheric transport (TM3), the spatial fields of simulated <sup>13</sup>CO<sub>2</sub> and CO<sub>2</sub> exchange are translated to local δ<sup>13</sup>CO<sub>2</sub> anomalies, which are then compared to atmospheric measurements. We discuss the ability of the model to accurately simulate the atmospheric seasonal δ<sup>13</sup>CO<sub>2 </sub>cycle<sub>, </sub>which could prove to be a valuable novel observational constraint. The coupled simulation allows us to distinguish the relative importance of the biosphere and ocean in determining the seasonal cycle of δ<sup>13</sup>CO<sub>2 </sub>at different measurement sites across the world.</p><p>The amplitude of the seasonal cycle of δ<sup>13</sup>CO<sub>2 </sub>is of particular importance to quantify land biosphere processes. The decreasing δ<sup>13</sup>CO<sub>2 </sub>of the atmosphere during the last decades (Suess effect) leads to a divergence of the δ<sup>13</sup>C signature in assimilation and heterotrophic respiration, because of the long lifetime of soil pools. This is expected to lead to a high sensitivity of the seasonal amplitude to the amount of soil respiration. The effect of changes in soil turnover times on the simulated seasonal cycle is explored with factorial simulations of the Dynamic Global Vegetation Model LPX-Bern.</p>

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