[NMR paper] Characterization of doubly ionic hydrogen bonds in protic ionic liquids by NMR deuteron quadrupole coupling constants - Differences to H-bonds in amides, peptides and proteins
Characterization of doubly ionic hydrogen bonds in protic ionic liquids by NMR deuteron quadrupole coupling constants - Differences to H-bonds in amides, peptides and proteins
We present the first deuteron quadrupole coupling constants (DQCC) for selected protic ionic liquids (PILs) measured by solid-state NMR spectroscopy. The experimental data are supported by dispersion-corrected density functional theory (DFT-D3) calculations and molecular dynamics (MD) simulations. The DQCCs of the N-D bond in the triethylammonium cations are the lowest reported for deuterons in PILs indicating strong doubly ionic hydrogen bonds. The NMR coupling parameters are compared to those in amides, peptides, and proteins. The DQCCs show characteristic behaviour with increasing interaction strength of the counterion and variation of the H-bond motifs. We report the similar presence of the quadrupolar splitting pattern and the narrow liquid line in the NMR spectra over large temperature ranges, indicating the heterogeneous nature of PILs. The knowledge of DQCC is a prerequisite for studying the rotational dynamics by means of NMR quadrupolar relaxation time experiments.
Direct 13 C-detected NMR experiments for mapping and characterization of hydrogen bonds in RNA
Direct 13 C-detected NMR experiments for mapping and characterization of hydrogen bonds in RNA
Abstract
In RNA secondary structure determination, it is essential to determine whether a nucleotide is base-paired and not. Base-pairing of nucleotides is mediated by hydrogen bonds. The NMR characterization of hydrogen bonds relies on experiments correlating the NMR resonances of exchangeable protons and can be best performed for structured parts of the RNA, where labile hydrogen atoms are protected from solvent exchange. Functionally important regions in...
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02-06-2016 03:10 PM
Ionic liquids: Enzymatic cellulose processing
Ionic liquids: Enzymatic cellulose processing
http://www.spectroscopynow.com/common/images/thumbnails/1514834b12b.jpgThe promise of room temperature ionic liquids (RTILs) as alternatives to toxic and inflammable volatile organic solvents for green chemistry has been on the boil for at least a couple of decades. Now, team has found that enzymatic activity can be sustained in processing cellulose, from wood, for conversion of this raw material into other useful compounds.
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12-01-2015 10:21 AM
Electron Spin–Lattice Relaxation Mechanisms of Nitroxyl Radicals in Ionic Liquids and Conventional Organic Liquids: Temperature Dependence of a Thermally Activated Process
From The DNP-NMR Blog:
Electron Spin–Lattice Relaxation Mechanisms of Nitroxyl Radicals in Ionic Liquids and Conventional Organic Liquids: Temperature Dependence of a Thermally Activated Process
A detailed understanding of the electron-spin relaxation mechanisms in polarizing agents used for DMP-NMR spectroscopy is crucial for the understanding of the DNP process and to optimize polarizing agents for different DNP applications. The entire study was performed at X-Band frequencies (9 GHz, 14 MHz 1H) and provides many details about the relaxation behavior of nitroxide radicals -...
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07-08-2015 11:11 PM
[NMR paper] Fast-pulsing NMR techniques for the detection of weak interactions: successful natural abundance probe of hydrogen bonds in peptides.
Fast-pulsing NMR techniques for the detection of weak interactions: successful natural abundance probe of hydrogen bonds in peptides.
http://www.bionmr.com//www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www.rsc.org-images-entities-char_z_RSClogo.gif Related Articles Fast-pulsing NMR techniques for the detection of weak interactions: successful natural abundance probe of hydrogen bonds in peptides.
Org Biomol Chem. 2013 Nov 21;11(43):7611-5
Authors: Altmayer-Henzien A, Declerck V, Aitken DJ, Lescop E, Merlet D, Farjon J
Abstract
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07-27-2014 01:05 AM
[NMR paper] Investigation of the NMR spin-spin coupling constants across the hydrogen bonds in ub
Investigation of the NMR spin-spin coupling constants across the hydrogen bonds in ubiquitin: the nature of the hydrogen bond as reflected by the coupling mechanism.
Related Articles Investigation of the NMR spin-spin coupling constants across the hydrogen bonds in ubiquitin: the nature of the hydrogen bond as reflected by the coupling mechanism.
J Am Chem Soc. 2004 Apr 28;126(16):5093-107
Authors: Tuttle T, Kraka E, Wu A, Cremer D
The indirect scalar NMR spin-spin coupling constants across the H-bonds of the protein ubiquitin were calculated,...
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11-24-2010 09:51 PM
[NMR paper] Solution NMR characterization of hydrogen bonds in a protein by indirect measurement
Solution NMR characterization of hydrogen bonds in a protein by indirect measurement of deuterium quadrupole couplings.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles Solution NMR characterization of hydrogen bonds in a protein by indirect measurement of deuterium quadrupole couplings.
J Magn Reson. 1997 Jul;127(1):54-64
Authors: Liwang AC, Bax A
Hydrogen bonds stabilize protein and nucleic acid structure, but little direct spectroscopic data have been available for...
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08-22-2010 03:31 PM
[NMR paper] Solution NMR characterization of hydrogen bonds in a protein by indirect measurement
Solution NMR characterization of hydrogen bonds in a protein by indirect measurement of deuterium quadrupole couplings.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles Solution NMR characterization of hydrogen bonds in a protein by indirect measurement of deuterium quadrupole couplings.
J Magn Reson. 1997 Jul;127(1):54-64
Authors: Liwang AC, Bax A
Hydrogen bonds stabilize protein and nucleic acid structure, but little direct spectroscopic data have been available for...
Characterization of doubly ionic hydrogen bonds in protic ionic liquids by NMR deuteron quadrupole coupling constants - Differences to H-bonds in amides, peptides and proteins
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