Structure and dynamics studies by solid-state NMR spectroscopy

Abstract

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2002.Vita.Includes bibliographical references.The major goal of this work is the development of high resolution solid state 205T1 NMR techniques and their application to the elucidation of the mechanism and dynamics of ion exchange in biological solids. The thesis starts with a review of recent progress in solid state NMR spectroscopy. The importance of directly observing ions in biological systems is discussed, and the advantages of 205T1 spectroscopy are noted of. Theoretical framework of the NMR experiments is described in chapter 2. The third chapter presents the development of methodology for solid state 205T1 NMR. The difficulties of 205T1 NMR are identified, and ways to circumvent the limitations are discussed. Several model compounds convenient for calibration of the key experimental parameters are discussed. The 205T1 direct excitation and H-205T1 cross polarization experiments are demonstrated. The fourth chapter describes the application of 205T1 high resolution solid state NMR to the investigation of the behavior of a small ion channel in the liquid crystalline phase. Here, thallium binding to gramicidin A in DMPC bilayers has been studied. Additional applications of 205T1 NMR to study liquid crystalline phases are also discussed. A summary and the future directions of the 205T1 NMR spectroscopy are presented in chapter 5.(cont.) The sixth chapter describes a 129Xe-19F high resolution solid state NMR study of crystalline XeF2. The absence of trapped Xe gas in crystalline XeF2 has been demonstrated. The 129Xe chemical shift anisotropy parameters have been extracted, and 19F-129Xe J-coupling has been measured. Progress in NMR spectroscopy is largely dependent on the capabilities and limitations of the experimental hardware. Chapter 7 presents a brief review of the development of probes for solid state NMR experiments. A triple channel H-13C-15N transmission line probe designed and constructed by the author is described.by Boris Arkadievich Itin.Ph.D