IN LIQUID-STATE DYNAMIC NUCLEAR POLARIZATION USING NITROXIDE RADICAL


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Engin Kırımlı H.

4. INTERNATIONAL 19 MAY INNOVATIVE SCIENTIFIC APPROACHES CONGRESS, Samsun, Turkey, 21 - 22 December 2020, pp.6-7

  • Publication Type: Conference Paper / Summary Text
  • City: Samsun
  • Country: Turkey
  • Page Numbers: pp.6-7

Abstract

Solution-state dynamic nuclear polarization (DNP) is an increasingly popular method of enhancing nuclear spin polarization that has many applications in nuclear magnetic resonance (NMR). One of the ways to increase the NMR signal is to enhance the nuclei magnetization by the methods of DNP based on the effect of transfer the polarization from electronic spins to a system of nuclear spins. In liquids the Overhauser mechanism (ODNP) makes the largest contribution to the polarization transfer.

Recently, nitroxide radical and its derivatives has been used as new potential polarizers for liquid DNP. By ODNP technique, 1H Overhauser dynamic nuclear polarization parameters at 1.5 mT such as the enhancement factor, the ultimate enhancement factor, the nuclear-electron coupling parameter, the importance on dependent scalar coupling parameter, the saturation factor and the leakage factor were determined for 4-Fluorobenzylbromide solvent with the nitroxide free radical in three different concentrations have been stuied with oxygen removed. The fundamental parameter in a DNP experiment is the nuclear-electron coupling factor, since it determines the maximum NMR signal enhancements which can be achieved. The nuclear-electron coupling factor contains information about the system dynamics. In a typical measurement, enhancements are measured as a function of the microwave power and the maximum enhancement is calculated from extrapolating to infinite power. The coupling factor can vary from -1 in the case of pure scalar coupling to +0.5 in the case of pure dipolar coupling. The results of our studies and the calculated parameters, especially the coupling parameter, indicates that there were scalar interactions between the nuclear spin and the electron spin.