Solid State Nuclear Magnetic Resonance on Quadrupolar Nuclei in Disordered Catalysis Based Materials PDF Download

Author: Thomas J. N. Hooper
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 0

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Author: Davis Sherman Rovnyak
Publisher:
ISBN:
Category :
Languages : en
Pages : 218

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Author: Robert Alan Kinsey
Publisher:
ISBN:
Category :
Languages : en
Pages : 390

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Author: Andre Sutrisno
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Preparation and characterization of inorganic materials is a crucial practice because understanding the relationship between structure and property is important for improving current performance and developing novel materials. Many metal centers in technologically and industrially important materials are unreceptive low- quadrupolar nuclei (i.e., possessing low natural abundance, low NMR frequencies and large quadrupole moments) and they usually give rise to very broad NMR resonances and low signal-to-noise ratios, making it difficult to acquire their solid-state NMR spectra. This thesis focuses on the characterization of inorganic materials using solid-state NMR (SSNMR) spectroscopy at very high magnetic field of 21.1 T in combination with quantum chemical calculations for computational modeling. In the first part of this thesis, 67Zn and 17O SSNMR studies of several microporous materials were reported. The results of 67Zn SSNMR studies from several important metal-organic frameworks (MOFs), in particular, zeolitic imidazolate frameworks (ZIFs) were presented. 67Zn SSNMR spectroscopy was used to gain structural information regarding the desolvation process in MOF-5. Furthermore, 67Zn SSNMR spectroscopy were utilized to study the host-guest interactions in ZIF-8 loaded with different guest molecules. Static 67Zn SSNMR spectra of microporous zinc phosphites (ZnP) and zinc phosphates (ZnPO) were also acquired at natural abundance. The Gaussian calculation results on a model cluster for ZnP indicate that Zn-O bond length is the most dominant factor to the observed quadrupolar coupling constant (CQ) among other geometric parameters around Zn centres. The local structures of the framework oxygen sites in molecular sieve SAPO-34 were directly probed by several 17O SSNMR techniques. The involvement of water vapor during the SAPO-34 formation in dry-gel conversion (DGC) synthesis was also investigated. In the second part, 91Zr and 33S SSNMR spectra of layered zirconium phosphates (ZrP) and transition metal disulfides (MS2) were obtained. The empirical correlations between NMR parameters and various structural parameters were used for obtaining partial structural information in Li+ and Co(NH3)63+ exchanged layered ZrP. For a series of closely related MS2 materials, the observed differences in the CQ(33S) values were rationalized by considering the difference in their geometrical arrangements. The final part of this thesis featured two examples of SSNMR spectroscopy of exotic nuclei in some interesting inorganic materials. (i) The experimental 135/137Ba SSNMR spectroscopy and theoretical studies of -BBO, an important non-linear optical (NLO) material, indicate that the true crystal structure of -BBO is R3c space group rather than R3. (ii) An ultrahigh field natural abundance 73Ge SSNMR study of two representative germanium containing materials [GeCl2-dioxane and GePh4] demonstrated that acquiring 73Ge wideline NMR spectra of germanium compounds where the Ge experiences an extremely large quadrupolar interaction is feasible and that the small 73Ge chemical shielding anisotropy (CSA) can be directly measured.

Author: Kevin Burgess
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Category : University of Ottawa theses
Languages : en
Pages :

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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 zexoticy 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.

Author: Roderick E. Wasylishen
Publisher: John Wiley & Sons
ISBN: 1118588843
Category : Science
Languages : en
Pages : 564

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NMR OF QUADRUPOLAR NUCLEI IN SOLID MATERIALS Over the past 20 years technical developments in superconducting magnet technology and instrumentation have increased the potential of NMR spectroscopy so that it is now possible to study a wide range of solid materials. In addition, one can probe the nuclear environments of many other additional atoms that possess the property of spin. In particular, it is possible to carry out NMR experiments on isotopes that have nuclear spin greater that 1⁄2 (i.e. quadrupolar nuclei). Since more that two-thirds of all NMR active isotopes are quadrupolar nuclei, applications of NMR spectroscopy with quadrupolar nuclei are increasing rapidly. The purpose of this handbook is to provide under a single cover the fundamental principles, techniques and applications of quadrupolar NMR as it pertains to solid materials. Each chapter has been prepared by an expert who has made significant contributions to out understanding and appreciation of the importance of NMR studies of quadrupolar nuclei in solids. The text is divided into three sections: The first provides the reader with the background necessary to appreciate the challenges in acquiring and interpreting NMR spectra of quadrupolar neclei in solids. The second presents cutting-edge techniques and methodology for employing these techniques to investigate quadrupolar nuclei in solids. The final section explores applications of solid-state NMR studies of solids ranging from investigations of dynamics, characterizations of biological samples, organic and inorganic materials, porous materials, glasses, catalysts, semiconductors and high-temperature superconductors. About EMR Handbooks The Encyclopedia of Magnetic Resonance (EMR) publishes a wide range of online articles on all aspects of magnetic resonance in physics, chemistry, biology and medicine. The existence-of this large number of articles, written by experts in various fields, is enabling the publication of a series of EMR Handbooks on specific areas of NMR and MRI. The chapters of each of these handbooks will comprise a carefully chosen selection of Encyclopedia articles. In consultation with the EMR Editorial Board, the EMR Handbooks are coherently planned in advance by specially-selected Editors, and new articles, are written (together with updates of some already existing articles) to give appropriate complete coverage. The handbooks are intended to be of value and interest to research students, postdoctoral fellows and other researchers learning about the scientific area in question and undertaking relevant experiments, whether in academia or industry. Have the content of this handbook and the complete content of the Encyclopedia of Magnetic Resonance at your fingertips! Visit: www.wileyonlinelibrary.com/ref/emr

Author: Mark Strohmeier
Publisher:
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Category : Carbon
Languages : en
Pages : 360

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Author: Sungsool Wi
Publisher:
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Category :
Languages : en
Pages : 534

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Author: Hye Kyung Cho Timken
Publisher:
ISBN:
Category :
Languages : en
Pages : 406

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Author: Roshanak Teymoori
Publisher:
ISBN:
Category : Nuclear magnetic resonance
Languages : en
Pages : 276

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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.