High DNP efficiency of TEMPONE radicals in liquid toluene at low concentrations.
نویسندگان
چکیده
We show that at low concentrations (≤5 mM) TEMPONE radicals in liquid toluene exhibit higher DNP efficiency than in water. In spite of reduced coupling factors, the improved DNP performance in toluene results from favourable saturation and leakage factors, as determined by pulse electron-electron double resonance (ELDOR) and NMR relaxation, respectively. The extracted coupling factors at 0.35 Tesla support theoretical predictions of the Overhauser mechanism.
منابع مشابه
Saturation factor of nitroxide radicals in liquid DNP by pulsed ELDOR experiments.
We propose the use of the pulse electron double resonance (ELDOR) method to determine the effective saturation factor of nitroxide radicals for dynamic nuclear polarization (DNP) experiments in liquids. The obtained values for the nitroxide radical TEMPONE-D,(15)N at different concentrations are rationalized in terms of spin relaxation and are shown to fulfil the Overhauser theory.
متن کاملHigh-field liquid state NMR hyperpolarization: a combined DNP/NMRD approach.
Here we show how fast dynamics between radicals and solvent molecules in liquid solutions can be detected by comparison of coupling factors determined by nuclear magnetic relaxation dispersion (NMRD) measurements and dynamic nuclear polarization (DNP) enhancement measurements at high magnetic field (9.2 T). This is important for a theoretical understanding of the Overhauser DNP mechanism at hig...
متن کاملOverhauser DNP with 15N labelled Frémy's salt at 0.35 Tesla.
The effectiveness of dynamic nuclear polarization (DNP) as a tool to enhance the sensitivity of liquid state NMR critically depends on the choice of the optimal polarizer molecule. In this study the performance of (15)N labelled Frémy's salt as a polarizing agent in Overhauser DNP is investigated in detail at X-band (0.35 T, 9.7 GHz EPR, 15 MHz (1)H NMR) and compared to that of TEMPONE-D,(15)N ...
متن کاملComputation of DNP coupling factors of a nitroxide radical in toluene: seamless combination of MD simulations and analytical calculations.
Dynamic nuclear polarization (DNP) employs paramagnetic species to increase the NMR signal of nuclear spins. In liquids, the efficiency of the effect depends on the strength of the interaction between the electron and nuclear spins and the time scales on which this interaction is modulated by the physical motion of the spin-bearing molecules. An approach to quantitatively predict the contributi...
متن کاملA high saturation factor in Overhauser DNP with nitroxide derivatives: the role of (14)N nuclear spin relaxation.
Overhauser DNP enhancements of toluene were measured at a magnetic field of 0.35 Tesla in a series of chemically functionalized nitroxide radicals. We observe that the enhancements increase systematically with polarizer size and rotational correlation time. Examination of the saturation factor of (14)N nitroxides by pulsed ELDOR spectroscopy led to a quantitative interpretation of the enhanceme...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Physical chemistry chemical physics : PCCP
دوره 16 19 شماره
صفحات -
تاریخ انتشار 2014