Expanding the frontiers of solid-state NMR spectroscopy: Techniques and applications for quadrupolar nuclei and structural analysis
Date
2025-05
Authors
Lamahewage, Sujeewa Nilantha Sampath
Major Professor
Advisor
Rossini, Aaron J
Smith, Emily
Huang, Wenyu
Venditti, Vincenzo
Vela, Javier
Committee Member
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Abstract
This dissertation explores advanced solid-state nuclear magnetic resonance (NMR) techniques and their applications in characterizing organometallic compounds, coordination compounds, metal halides and nano-scale oxides and semiconductors. We demonstrate novel indirect detection methods, using double-echo resonance-echo saturation-pulse double-resonance (DE-RESPDOR) and J-resolved NMR experiments to detect solid-state NMR spectra of half-integer quadrupolar nuclei with enhancing sensitivity and/or resolution. These solid-state NMR techniques are then applied to investigate hybrid metal halides, revealing complex structural ordering driven by molecular dipoles. Furthermore, metal-oxygen scalar couplings in coordination compounds are measured, laying the groundwork for characterizing carboxylate ligand-capped nanomaterials relevant to energy applications. The local oxygen environments and structural dynamics of one-dimensional lepidocrocite titanate nanofilaments are elucidated using 17O solid-state NMR and density functional theory calculations, demonstrating the power of combined experimental and computational approaches in characterizing quantum-confined materials. Finaly, the study also explores the stability and relaxation properties of encapsulated atomic hydrogen radicals in polyhedral oligomeric silsesquioxane (POSS) cages, highlighting their potential in quantum computing and dynamic nuclear polarization. Collectively, this work advances solid-state NMR methodologies and provides crucial structural and dynamic information for a wide array of materials with significant technological implications.
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dissertation