NMR Characterization of Molecular Structure and Dynamics in Ligand-Capped Metal and Metal Oxide Nanoparticles

Project: Research project

Description

The objective of the proposed research is to synthesize ligand-capped metal and inorganic oxide NPs (NPs) and to develop NMR methods to characterize the capping chemistry and nanoparticle structure. The broader impact of the proposed research will come in several forms, including (i) elucidating the structure of an important class of nanomaterials and providing general characterization techniques for the nano-materials research communities, (ii) training the next generation of materials chemists and NMR spectroscopists, and (iii) develop educational outreach in the area of nano-chemistry to local high school teachers and classrooms. A list of specific aims that Profs Holland and Yarger hope to achieve in the proposed research is given below: Continued synthesis of gold (Au) and silver (Ag) NPs along with preparation and purification of SiO2, SnO2, and V2O5 NPs with a focus on phosphonate, silane and phosphine capping agents. Emphasis will be placed on mixtures of capping ligands to enhance surface functionality and study ligand intermolecular interactions and surface organization. Design and development of solution NMR techniques to characterize the aforementioned NPs and the associated ligand capping chemistry. Focus will be on understanding structure, dynamics and ligand chemical exchange processes. Also, the use of pulsed field gradient spinecho (PFG-SE) and stimulated-echo (PFG-STE) NMR methods to examine nanoparticle mobility in organic and aqueous environments. Use of modern solid-state NMR techniques (e.g. 2D CP-MAS with radio frequency dipolar recoupling [RFDR]) to provide surface selectivity and spatial correlation in characterization of nanoparticle capping and heterogeneous intermolecular organization and morphology (e.g. proton spin-diffusion measurements). Furthermore, we will use 6,7Li MAS NMR to interrogate the structure and dynamics of Li+ in battery-related NP systems (e.g. SnO2 and V2O5). The primary intellectual merit of the proposed project is focused on uncovering fundamental chemistries both structural and dynamic at the NP-ligand interface using a suite of NMR spectroscopy techniques from both the solids and liquid state NMR sciences. It is our hopes that this will lead to a broader impact in nanoscience by providing generalized NMR techniques and analysis for the characterization of ligand-capped NPs.
StatusFinished
Effective start/end date9/15/108/31/14

Funding

  • National Science Foundation (NSF): $405,000.00

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Oxides
Molecular structure
Molecular dynamics
Metals
Nuclear magnetic resonance
Nanoparticles
Ligands
phosphine
Nanoscience
Silanes
Organophosphonates
Silver
Nanostructured materials
Gold
Nuclear magnetic resonance spectroscopy
Purification
Protons
Liquids