Ravera Enrico, Luchinat Claudio, Parigi Giacomo
Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy.
Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy.
J Magn Reson. 2016 Mar;264:78-87. doi: 10.1016/j.jmr.2015.12.013.
After the first surprisingly large (1)H DNP enhancements of the water signal in aqueous solutions of nitroxide radicals observed at high magnetic fields, Overhauser DNP is gaining increasing attention for a number of applications now flourishing, showing the potentialities of this mechanism in solution and solid state NMR as well as in MRI. Unexpected Overhauser DNP enhancements in insulating solids were recently measured at 100K, with a magnitude which increases with the applied magnetic field. We recapitulate here the theoretical premises of Overhauser DNP in solution and analyze the effects of the various parameters on the efficacy of the mechanism, underlining the link between the DNP enhancements and the field dependent relaxation properties. Promisingly, more effective DNP enhancements are expected by exploiting the potentialities offered by (13)C detection and the use of supercritical fluids.
在高磁场下观察到一氧化氮自由基水溶液中水信号的首个令人惊讶的大的（1）H DNP增强之后，奥弗豪泽动态核极化（Overhauser DNP）因其在众多蓬勃发展的应用中日益受到关注，展现了该机制在溶液和固态核磁共振以及磁共振成像中的潜力。最近在100K下测量了绝缘固体中意外的奥弗豪泽DNP增强，其幅度随外加磁场增加。我们在此概括溶液中奥弗豪泽DNP的理论前提，并分析各种参数对该机制功效的影响，强调DNP增强与场依赖弛豫特性之间的联系。有望通过利用（13）C检测提供的潜力和使用超临界流体实现更有效的DNP增强。
