Dynamic nuclear-polarization studies of paramagnetic species in solution

Technical Report · Thu Jul 01 04:00:00 EDT 1982

DOI:https://doi.org/10.2172/6855699· OSTI ID:6855699

Glad, W E

Dynamic Nuclear Polarization (DNP) was used to measure the electron spin lattice relaxation times, T/sub 1/, of transition metal ions in aqueous solution. Saturation which is induced in the electron spin system is transferred to the solvent proton spins by dipole-dipole interactions. The change in the polarization of the proton spins is much larger than it is in the electron spins. The change in proton polarization is easily measured by proton Nuclear Magnetic Resonance (NMR). In one experimental arrangement the sample solution was continuously flowed through a microwave cavity to the NMR coil. The NMR was observed with a continuous wave NMR spectrometer. In a second arrangement the whole sample tube was moved from within the microwave cavity to the NMR coil in less than 40 ms by a blast of compressed air. The NMR was then observed with a pulse-Fourier-transform spectrometer. With the second arrangement a mean-square microwave magnetic field at the sample of more than 10 G/sup 2/ is obtainable with 14 W of microwave power. Measurements of DNP at 9 GHz were made on aqueous solutions of VO/sup 2 +/, Mn/sup 2 +/, Cr(CN)/sub 6//sup 3 -/, Cu/sup 2 +/ and Cu(ethylenediamine)/sub 2/(H/sub 2/0)/sub 2//sup 2 +/ ions from 3 to 60/sup 0/C. It was also possible to observe DNP on resolved proton resonances from mixed water-acetonitrile solutions of VO/sup 2 +/ and Cr(CN)/sub 6//sup 3 -/ ions.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6855699
• Report Number(s): LBL-14625; ON: DE83001533
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AQUEOUS SOLUTIONS
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
CHROMIUM COMPOUNDS
COPPER COMPOUNDS
DISPERSIONS
ELEMENTS
IONS
MAGNETIC RESONANCE
MANGANESE COMPOUNDS
METALS
MIXTURES
NUCLEAR MAGNETIC RESONANCE
OXIDES
OXYGEN COMPOUNDS
RELAXATION
RESONANCE
SOLUTIONS
SPIN-LATTICE RELAXATION
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VANADIUM COMPOUNDS
VANADIUM OXIDES