Triple resonance solid-state NMR for multi-nuclear studies

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The suite of equipment requested here will enable triple resonance nuclear magnetic resonance (NMR) spectroscopy on our solid-state AV 500 NMR spectrometer.  The critical components include the triple resonance 4mm magic angle spinning probe (1H/19F, X, Y) and the 500W amplifier for a third channel, as well as the accompanying hardware for incorporating a third channel into the existing spectrometer console.  This new equipment will meet the needs of several research projects within our group, and significantly expand the capacity of this spectrometer.      Rechargeable lithium polymer batteries find many uses in portable electronics, and are poised to lead major breakthroughs in the area of zero emission vehicles.  The success of new materials is governed by their ability to reversibly transport lithium ions.  A class of cathode materials which have received much attention lately are the transition metal phosphates, which have open framework structures that facilitate ion transport.  The measurement of residual dipolar couplings is powerful method for characterizing local dynamics, well-known in the protein NMR community, but pioneered in our group in its application to solid-state ionic conductors. The new suite of equipment will allow us to investigate lithium ion dynamics using a new spectroscopic handle, namely the 6Li-31P dipolar coupling.      Polymer-electrolyte membranes for fuel cells, which can provide environmentally friendly energy, rely on membranes able to conduct protons. Many of the competitive polymer candidates are perfluorinated materials.  The probe requested here will facilitate excellent 19F NMR, at MAS frequencies of 24kHz, sufficient to eliminate sidebands from the spectral region of interest.  The new probe will allow us to characterize backbone dynamics in Nafion and its numerous analogues, by measuring both 19F directly, and 19F-13C cross polarization enhanced spectra.  New collaborations with synthetic groups who are designing novel fluorinated proton-conducting polymers will be enabled.