Dynamic NMR Spectroscopy in Inorganic and Organometallic Chemistry

Abstract

Publisher Summary This chapter provides an overview of the recent developments in dynamic NMR (DNMR) techniques and describes their applications to inorganic and organometallic chemistry. The chapter also emphasizes the challenges presented to NMR spectroscopists by the diverse and complex stereodynamical rearrangements displayed by many inorganic and organometallic compounds. The chapter essentially considers studies that concern (1) an important development of the DNMR theory; (2) an important advance in DNMR bandshape, relaxation time, or magnetization transfer technique; (3) new and accurate rate constant or energy barrier data; and (4) new and novel dynamic processes. Developments in DNMR techniques include exchange theory and total bandshape analysis, spin-lattice relaxation-time measurements, spin-spin relaxation-time measurements, magnetization-transfer experiments, two-dimensional experiments, and oriented solute studies. In specific, spin-lattice relaxation studies can effectively yield useful information about rapid molecular motions on a time scale that is far shorter than is associated with bandshape analysis. The NMR spectra of molecules partially oriented in liquid-crystal solvents are often dominated by large interactions such as direct dipole-dipole or quadrupolar couplings. Such couplings lead to very large characteristic splitting in the NMR spectra, which opens the possibility of studying chemical exchange processes by lineshape analysis over a wider range of rates as compared to isotropic solvents.