Solid-state NMR of exotic nuclei in inorganic, organometallic and composite materials

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Solid-state nuclear magnetic resonance (SSNMR) is a technique that has come to the forefront for characterizing structure and dynamics in solid materials at the molecular level.  However, there are many elements in the periodic table that have traditionally not been subject to NMR investigation, due to the low receptivity of their nuclei.  Nuclei are classified as unreceptive due to low resonance frequencies, low natural abundances, broad NMR powder patterns and long relaxation times, all of which can make the acquisition of a routine NMR spectrum last for days or even weeks!  We are proposing to develop and apply pulse sequences, in combination with special hardware and high magnetic fields which will greatly reduce experiment times, to enable the routine investigation of nuclei across the periodic table in a series of interesting inorganic, organometallic and composite materials with SSNMR. Using these methodologies, we are proposing to investigate three major classes of materials, including (i) metallocenes, (ii) composite materials and (iii) nanoparticles.  (i) Metallocenes are of great interest for their diverse chemistry and use in many industrial processes.  SSNMR, computational chemistry and X-ray diffraction techniques will be used to study the structural variability of metallocenes, as well as their function in heterogeneous catalysis of polymers.  (ii) We will study two types of composite materials: mesoporous metal oxides (MMOs) and supramolecular solids.  MMOs have large pores that can physically or chemically trap a variety of molecules, and have walls with which interesting redox chemistry can be conducted.  The latter are silver coordination solids which selectively adsorb primary amines.  NMR will be used to probe the structures of the host materials, as well as interactions with the guest molecules.  (iii) Nanoparticles (NPs) have recently generated much excitement, due to their unique optical and electrical properties and utility as building blocks for macroscopic materials.  We plan to study the cores and surfaces of a series of NPs of different compositions, including LaF3, CdS and CdSe and Au.