In the past decade, the field of NMR spectroscopy has seen the emergence of ever more powerful superconducting magnets, which has opened the door for the observation of many traditionally challenging or non-receptive nuclei. In this dissertation, a variety of ionic solids with organic coordination environments are investigated using quadrupolar solid-state NMR experiments with an ultrahigh-field magnet (21.1 T). Two general research directions are presented including a 79/81Br solid-state NMR study of a series of 6 triphenylphosphonium bromides for which single-crystal X-ray structures are reported herein. A second research direction is also presented wherein alkaline-earth metal (25Mg, 43Ca, and 87Sr) solid-state NMR is used to characterize a systematic series of 16 aryl and alkyl carboxylates. In both studies, the quadrupolar nuclei studied are deemed “exotic” due to their unreceptive nature to NMR spectroscopic analysis including low natural abundances, large quadrupole moments, or low resonance frequencies. A variety of coordination modes to alkaline-earth metals, including N-atom coordination, are characterized herein for the first time using alkaline-earth metal solid-state NMR. In all cases, the electric field gradient (EFG) and chemical shift (CS) tensors are characterized and correlated to structural features such as interatomic distances measured from the crystal structure of the compound under study. In all of the projects undertaken herein, the gauge-including projector-augmented-wave density functional theory (GIPAW DFT) method is used, which allows for the prediction and rationalization of the experimental EFG and CS tensor parameters based on the input crystal structure. In the case of 43Ca solid-state NMR experiments reported in this dissertation, a linear correlation between the calculated and experimental 43Ca quadrupolar coupling constants, CQ, is used as a calibration curve for GIPAW DFT calculations performed on the 18 structural models currently available for the vaterite polymorph of CaCO3. Vaterite cannot be fully characterized by X-ray diffraction alone; therefore an NMR crystallography protocol is used in order to identify the model that best accounts for 43Ca solid-state NMR experiments performed on vaterite. It is expected that the conclusions from this dissertation can be used for future studies involving structural refinement and elucidation of solid materials containing challenging quadrupolar nuclei.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

The concept of noncovalent bonding has evolved over the last number of years to include a very interesting class of interactions that is analogous to hydrogen bonding, called σ-hole interactions. These result from the depletion of electrostatic charge on the opposite end of a covalent bond between an electron-withdrawing substituent and a bond donor atom, which resides in groups 14-17 of the periodic table. One of these interactions is the tetrel bond (TB), whereby the bond donor is a group 14 element (T=C, Si, Ge, Sn, Pb). This thesis's primary goal is to explore the solid-state NMR parameters arising from the formation of tetrel bonds. To this end, combined density functional theory (DFT) and experimental multinuclear solid-state NMR spectroscopic investigations are carried out on complexes featuring carbon, Pb(II) and tin tetrel bonds. Firstly, solid-state NMR and computational approaches are used to examine a series of cocrystals formed from either caffeine or theophylline and several other small organic acceptor molecules. It is shown that the NMR response due to tetrel bond formation is detectible, but it can be hidden by other effects, including those of crystal packing. Careful analysis of NMR data alongside DFT calculations can reveal that the weak tetrel bond in these sorts of complexes increases the ¹³C chemical shift by 3-5 ppm. Next, a study of five Pb(II) centres hemidirectionally coordinated by isonicotinoyl hydrazone ligands demonstrates that the ²⁰⁷Pb NMR response is highly sensitive to the Pb(II) coordination environment. The NMR data indicate that a tetrel bond can induce an NMR response corresponding to a coordination environment between hemidirectional and holodirectional character. Finally, a series of organotin chloride donor molecules complexed with N-oxides and carboxylates, which feature short and linear tetrel bonds, are subjected to magic angle spinning (MAS) NMR experiments. The recorded data gives rise to a correlation between the tetrel bond length and both the experimental chemical shift and the ¹J(¹¹⁹Sn-³⁵Cl) coupling. Throughout this thesis, it is demonstrated that the isotropic chemical shift, the principal components of the chemical shift tensor, and indirect spin-spin coupling can be used to probe and gain insights into the electronic environment at the tetrel bond. More importantly, this work is fundamental to rationalize NMR data while refining crystal structure data in NMR crystallographic approaches for compounds featuring tetrel bonds.

No description available.

Lithium-ion batteries have transformed energy storage and technological applications. They stand poised to convert transportation from combustion to electric engines. The discharge/charge rate is a key parameter that determines battery power output and recharge time; typically, operation is on the timescale of hours but reducing this would improve existing applications and open up new possibilities. Conventionally, the rate at which a battery can operate has been improved by synthetic strategies to decrease the solid-state diffusion length of lithium ions by decreasing particle sizes down to the nanoscale. In this work, a different approach is taken toward next-generation high-power and fast charging lithium-ion battery electrode materials. The phenomenon of high-rate charge storage without nanostructuring is discovered in niobium oxide and the mechanism is explained in the context of the structure–property relationships of Nb2O5. Three polymorphs, T-Nb2O5, B-Nb2O5, and H-Nb2O5, take bronze-like, rutile-like, and crystallographic shear structures, respectively. The bronze and crystallographic shear compounds, with unique electrochemical properties, can be described as ordered, anion-deficient nonstoichiometric defect structures derived from ReO3. The lessons learned in niobia serve as a platform to identify other compounds with related structural motifs that apparently facilitate high-rate lithium insertion and extraction. This leads to the synthesis, characterisation, and electrochemical evaluation of the even more complicated composition–structure–property relationships in ternary TiO2–Nb2O5 and Nb2O5–WO3 phases. Advanced structural characterisation including multinuclear solid-state nuclear magnetic resonance spectroscopy, density functional theory, X-ray absorption spectroscopy, operando high-rate X-ray diffraction, and neutron diffraction is conducted throughout to understand the evolution of local and long-range atomic structure and changes in electronic states.