Panov, M., et al., Coherent Polarization Transfer Effects Are Crucial for Interpreting Low-Field CIDNP Data. Appl. Magn. Reson., 2014. 45(9): p. 893-900.
In this work we demonstrate that low-field chemically induced dynamic nuclear polarization (CIDNP) is strongly affected by re-distribution of polarization, which is formed in the course of spin evolution in transient radical pairs, in diamagnetic reaction products. This phenomenon is of importance when the spins of the reaction product are coupled strongly meaning that spin–spin interactions between them are comparable to the differences in their Zeeman interactions with the external magnetic field. In this case, polarization transfer relies on a coherent mechanism; as a consequence, spins can acquire significant polarization even when they have no hyperfine coupling to the electron spins in the radical pairs, i.e., cannot be polarized directly by CIDNP. This is demonstrated by taking CIDNP of n-butylamine as an example: in this case only the ?-CH2 protons are polarized directly, which is confirmed by high-field CIDNP, whereas the ?-CH2, ?-CH2 and ?-CH3 protons get polarized only indirectly due to the transfer of polarization from the ?-CH2 protons. These results show that low-field CIDNP data should be interpreted with care to discriminate between the effects of spin evolution in transient radical pairs and in diamagnetic reaction products.
[NMR paper] Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: Relaxing selective polarization transfer condition between two dilute spins.
Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: Relaxing selective polarization transfer condition between two dilute spins.
Related Articles Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: Relaxing selective polarization transfer condition between two dilute spins.
J Magn Reson. 2014 Mar 16;242C:214-219
Authors: Zhang Z, Fu R, Li J, Yang J
Abstract
Double cross polarization (DCP) has been widely used for heteronuclear polarization transfer between (13)C...
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Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: relaxing selective polarization transfer condition between two dilute spins
Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: relaxing selective polarization transfer condition between two dilute spins
Publication date: Available online 16 March 2014
Source:Journal of Magnetic Resonance</br>
Author(s): Zhengfeng Zhang , Riqiang Fu , Jianping Li , Jun Yang</br>
Double cross polarization (DCP) has been widely used for heteronuclear polarization transfer between 13C and 15N in solid-state magic-angle spinning (MAS) NMR. However, DCP is such sensitive to experimental settings that small variations or...
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Evidence for Coherent Transfer of para-Hydrogen-Induced Polarization at Low Magnetic Fields
From The DNP-NMR Blog:
Evidence for Coherent Transfer of para-Hydrogen-Induced Polarization at Low Magnetic Fields
Kiryutin, A.S., et al., Evidence for Coherent Transfer of para-Hydrogen-Induced Polarization at Low Magnetic Fields. The Journal of Physical Chemistry Letters, 2013. 4(15): p. 2514-2519.
http://dx.doi.org/10.1021/jz401210m
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Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Publication year: 2012
Source:Journal of Magnetic Resonance</br>
Zhengfeng Zhang, Yimin Miao, Xiaoli Liu, Jun Yang, Conggang Li, Feng Deng, Riqiang Fu</br>
A sinusoidal modulation scheme is described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. During the second N->C cross polarization, the 13C RF amplitude is...
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03-09-2012 09:16 AM
Interpreting protein chemical shift data
Interpreting protein chemical shift data
Publication year: 2011
Source:Progress in Nuclear Magnetic Resonance Spectroscopy, Volume 58, Issues 1–2</br>
David S. Wishart</br>
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Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Publication year: 2012
Source: Journal of Magnetic Resonance, Available online 5 March 2012</br>
Zhengfeng*Zhang, Yimin*Miao, Xiaoli*Liu, Jun*Yang, Conggang*Li, ...</br>
A sinusoidal modulation scheme is described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. During the second N->C cross polarization, theC RF amplitude is modulated...
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03-06-2012 06:04 AM
[NMR paper] Proton-transfer effects in the active-site region of Escherichia coli thioredoxin usi
Proton-transfer effects in the active-site region of Escherichia coli thioredoxin using two-dimensional 1H NMR.
Related Articles Proton-transfer effects in the active-site region of Escherichia coli thioredoxin using two-dimensional 1H NMR.
Biochemistry. 1991 Apr 30;30(17):4262-8
Authors: Dyson HJ, Tennant LL, Holmgren A
A series of two-dimensional (2D) correlated 1H NMR spectra of reduced and oxidized Escherichia coli thioredoxin have been used to probe the effects of pH in the vicinity of the active site, -Cys32-Gly-Pro-Cys35-, using the...
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08-21-2010 11:16 PM
Interpreting Protein Chemical Shift Data
Interpreting Protein Chemical Shift Data
Publication year: 2010
Source: Progress in Nuclear Magnetic Resonance Spectroscopy, In Press, Accepted Manuscript, Available online 5 August 2010</br>
David S., Wishart</br>
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