Solid-State Nuclear Magnetic Resonance and Computational Investigation of Half-integer Quadrupolar Nuclei

Abstract

This thesis is concerned with applications of modern solid-state NMR spectroscopy. Investigations of three quadrupolar nuclei (51V, 17O, and 23Na) are undertaken to demonstrate the practicality of solid-state nuclear magnetic resonance, SSNMR in studies of compounds containing these nuclei. The goal of each project is to gain insight into the effect of the local environment on the NMR observables. Vanadium-51 solid-state NMR has been used to study oxo- and peroxo-vanadium compounds. The 51V nucleus is examined to determine the vanadium magnetic shielding, MS and electric field gradient, EFG tensors. Density functional theory, DFT, has been utilized to calculate MS and EFG tensors to corroborate experimental data and to provide insight into the relationship between molecular and electronic structure. In addition the hyperbolic secant, HS pulse sequence has been used to provide spectra from which information about the shielding anisotropy of [V(O)(ONMe2)2]2O could be gained. An investigation of oxygen-17 solid-state NMR studies of ligand, 17OP(p-Anis)3 and complex of InI3[17OP(p-Anis)3]2 powder samples has also been carried out. Coordination of oxygen to indium causes a change in the 17O chemical shift tensor. DFT calculations are also utilized and the theoretical results are compared with the corresponding experimental values. Finally, solid-state sodium-23 NMR investigations of series of sodium salts, (sodium nitroprusside dihydrate, sodium bromate, sodium chlorate, sodium nitrate, sodium nitrite, sodium selenite and anhydrous disodium hydrogen phosphate) were carried out to determine 23Na MS and EFG tensor parameters. The CASTEP and BAND codes were employed to calculate the EFG and MS tensors. In addition, in the case of sodium nitroprusside solid-state 17O and 15N NMR studies, as well as computational investigations of the corresponding EFG and MS tensors, were undertaken. This Thesis reported the first experimental demonstration of sodium CS tensors determined from solid-state NMR spectroscopy of powder samples of these sodium salts. It also demonstrated the use of first-principles calculations, based on DFT theory in the CASTEP and BAND codes, to investigate the 23Na EFG and MS tensors for these sodium salts.