Low field nuclear magnetic resonance spectroscopy of hyperpolarized spin systems

• Niederfeldkernspinresonanzspektroskopie an hyperpolarisierten Spinsystemen

Colell, Johannes; Appelt, Stephan (Thesis advisor); Blümich, Bernhard (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2016)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2015

Abstract

Results of the dissertation must be divided into three sections. The first section is concerned with construction of a magnet system suitable for high-resolution low-field nuclear magnetic resonance spectroscopy which was planned, prepared and evaluated. In the following, the newly developed experimental setup was used for low-field nuclear magnetic resonance experiments in combination with hyperpolarization. In the second section the new setup was used for spectroscopy of hyperpolarized xenon and investigation of the Spin Polarization Induced Nuclear Overhauser Effect. In the third section parahydrogen induced polarization was investigated experimentally and theoretically. To Section 1: Due to the high precision requirements spectroscopy grade magnets all coils (1 mean field coil, 4 shim coils) were carefully measured and, if required, remade. The system was tested with current sources differing in temporal stability and theoretically and experimentally achievable homogeneities were compared. To Section 2: SPINOE Experiments in this section (1) revealed, that SPINOE is not limited to unpolar organic molecules. Furthermore, it was shown experimentally that the so-called "strongly coupled spin systems" exists at higher field strengths, where as expected, large heteronuclear coupling constants present in inorganic molecules shift the strong coupling regime to from earth's magnetic field to several mT fields.To Section 3: In order to advance the state of the theory of para-hydrogen induced polarization (PHIP) a compound suitable for investigation with the new setup under the restrictions imposed by the the performance parameters determined in section 1 was prepared. A suitable catalyst system for catalytic hydrogenation step of the para-hydrogen induced polarization step was localized. In the following the system was investigated by spectroscopy at different magnetic field strengths, made possible by the system constructed in section 1. The results obtained were used to derive and verify (2) the heteronuclear three-spin density matrix, which is a key reference point for PHIPexperiments. (1) Experiments were performed in Collaboration with the ERS visitors Prof. K. Ishikawa, Kyoto University and Dr. B. Patton, UC Berkeley. (2) In collaboration with M.Sc. P. Türschmann and Prof. S. Appelt.

Institutions

• Chair of Macromolecular Chemistry [154810]
• Department of Chemistry [150000]