Overhauser Dynamic Nuclear Polarization Parameters of a Nitroxide Radical in Liquid

Abstract

Solution state Overhauser-effect-type dynamic nuclear polarization (ODNP) has been studied in the last years. The basis of ODNP is a polarization mechanism that presents nuclei with electron spin polarization. ODNP enhancements studies are presented 4-fluorobenzyl alcohol (4FBA) with the stable nitroxide radical as the polarizing agent for 15, 30 and 60 mM concentrations at 1.53 mT. Major ODNP parameters were obtained. The significant parameter is the coupling parameter, since it determines the maximum NMR signal enhancements and the interactions between the nuclear spin and the electron spin. The coupling parameter can vary from -0.152 to 0.001. The obtained ODNP parameters show that both scalar and dipolar interactions occur. The results show that nitroxide radical can be taken as polarizing agent for ODNP studies of 4-fluorobenzyl alcohol solvent. The effect of dissolved molecular oxygen on the enhancement factor for the sample with the smallest concentration was experimentally investigated.

Keywords

• Dynamic nuclear polarization
• Overhauser effect
• free nitroxide radical
• 4-fluorobenzyl alcohol (4FBA)
• the polarizing agent

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