Recently, new applications of trityl-nitroxide biradicals were proposed. In the present study, attachment of a trityl radical to alkoxyamines was performed for the first time. The rate constants kd of C-ON bond homolysis in these alkoxyamines were measured and found to be similar to those for alkoxyamines without a trityl moiety. The electron paramagnetic resonance (EPR) spectra of the products of alkoxyamine homolysis (trityl-TEMPO and trityl-SG1 biradicals) were recorded, and the corresponding exchange interactions were estimated. The decomposition of trityl-alkoxyamines showed more than an 80% yield of biradicals, meaning that the C-ON bond homolysis is the main reaction. The suitability of these labelled initiators/controllers for polymerisation was exemplified by means of a successful nitroxide-mediated polymerisation (NMP) of styrene. Thus, this is the first report of a spin-labelled alkoxyamine suitable for NMP.
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Measurements of short distances between trityl spin labels with CW EPR, DQC and PELDOR
From The DNP-NMR Blog:
Measurements of short distances between trityl spin labels with CW EPR, DQC and PELDOR
This article does not describe any DNP-NMR experiments. However, in the light of biradicals as polarizing agents for DNP experiments it is still very interesting. Especially since trityl radicals have very narrow EPR lines and these biradicals could be more efficient to polarize low-gamma nuclei such as 13C, 29Si or 15N.
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01-08-2014 11:53 PM
Intermediate Dipolar Distances from Spin Labels
Intermediate Dipolar Distances from Spin Labels
Publication date: Available online 16 November 2013
Source:Journal of Magnetic Resonance</br>
Author(s): Derek Marsh</br>
Methods for determining inter-spin distances between nitroxide spin labels from dipolar couplings in the intermediate range (r 12 ? 1.1-2 nm) by CW-EPR are addressed. For nitroxide powder patterns, the assumption of unlike spins is a better approximation than assuming strong coupling between like spins. Methods that determine the average splitting in dipolar deconvolutions yield the mean value ?...
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11-17-2013 07:00 AM
Electron spin resonance studies of trityl OX063 at a concentration optimal for DNP
From The DNP-NMR Blog:
Electron spin resonance studies of trityl OX063 at a concentration optimal for DNP
Lumata, L., et al., Electron spin resonance studies of trityl OX063 at a concentration optimal for DNP. Phys. Chem. Chem. Phys., 2013. 15(24): p. 9800-9807.
http://dx.doi.org/10.1039/C3CP50186H
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06-10-2013 05:30 PM
Conformational dynamics and distribution of nitroxide spin labels
Conformational dynamics and distribution of nitroxide spin labels
Publication date: Available online 18 April 2013
Source:Progress in Nuclear Magnetic Resonance Spectroscopy</br>
Author(s): Gunnar Jeschke</br>
Long-range distance measurements based on paramagnetic relaxation enhancement (PRE) in NMR, quantification of surface water dynamics near biomacromolecules by Overhauser dynamic nuclear polarization (DNP) and sensitivity enhancement by solid-state DNP all depend on introducing paramagnetic species into an otherwise diamagnetic NMR sample. The species can be...
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04-18-2013 10:12 PM
[NMR paper] Spin labels as a tool to identify and characterize protein-ligand interactions by NMR
Spin labels as a tool to identify and characterize protein-ligand interactions by NMR spectroscopy.
Related Articles Spin labels as a tool to identify and characterize protein-ligand interactions by NMR spectroscopy.
Chembiochem. 2002 Mar 1;3(2-3):167-73
Authors: Jahnke W
NMR spectroscopy based discovery and optimization of lead compounds for a given molecular target requires the development of methods with maximum sensitivity and robustness. It is shown here that organic nitroxide radicals ("spin labels") can be used to boost the sensitivity...
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11-24-2010 08:49 PM
[NMR paper] An NMR investigation of the conformational effect of nitroxide spin labels on Ala-ric
An NMR investigation of the conformational effect of nitroxide spin labels on Ala-rich helical peptides.
Related Articles An NMR investigation of the conformational effect of nitroxide spin labels on Ala-rich helical peptides.
J Magn Reson. 1998 Apr;131(2):248-53
Authors: Bolin KA, Hanson P, Wright SJ, Millhauser GL
Nitroxide spin labels, in conjunction with electron spin resonance (ESR) experiments, are extensively employed to probe the structure and dynamics of biomolecules. One of the most ubiquitous spin labeling reagents is the...