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Hamilton hosted the 90^th Canadian Chemistry Conference and Exhibition (“CSC”) from May 30^th through June 3^rd, 2009.  Prof. Gillian Goward (McMaster University) and Prof. Alex Bain (McMaster University) organized a symposium entitled “Materials and Magnetic Resonance” which was jointly sponsored by the Divisions of Materials Chemistry, and Physical and Theoretical Chemistry.  The 2-day symposium was attended by over 75 students, academics, and industrial researchers.  It was a success, due in a large part to the support from the ACS-PRF, which allowed us to invite high-profile international speakers.  These speakers including Prof. Hans Wolfgang Spiess, director of the Max Planck Institute for Polymer Research in Mainz, Germany, and Prof. Sharon Ashbrook, from St. Andrews University in Scotland.

The symposium focused on Materials Science topics elucidated using Magnetic Resonance, including both spectroscopy and imaging strategies.  The magnetic resonances methods comprise an important widely used class of characterization strategies for materials including materials for efficient generation, storage and conversion of energy, as well as important catalysts used in the petroleum industry. The invited speakers addressed methodological advances in magnetic resonance and applications to materials of practical importance to the petrochemical industry :

·         Hans Wolfgang Spiess presented work on proton-conducting polymers, relevant to fuel cell applications, and the use of solid-state NMR to characterize local dynamics.  He also presented complementary work from his group on a range of olefinic polymer systems, and the application of solid-state NMR to study the polymer physics of these industrially relevant materials.

Title: Solid State NMR of Functional Soft Materials

Abstract:  The growing necessity for clean energy sources to substitute fossil energy has created high demands for batteries and fuel cells. Therefore, various approaches have been proposed, aiming at developing new classes of proton conducting membranes for high temperature applications, based on phosphonic acid.  From ¹H, ²H, ¹³C, and ³¹P NMR combined with computer simulation detailed information on the proton mobility can be obtained. High mobility is found for the protons, whereas on the same timescale no mobility associated with reorientation of the phosphonic acid groups or the polymer backbone is observed. The ¹H chemical shifts of P-OH protons provide evidence for the presence of a hydrogen bond network, which allows for proton transport via a Grotthus-type mechanism along a given chain as well as between adjacent chains. The MD simulations further show that proton vacancies can be trapped in anhydride defects produced by condensation.

·         Sharon E. Ashbrook presented new strategies for combining computational research with NMR spectroscopy, to elucidate structure and dynamics in complex disordered minerals.  These materials are studied for a variety of applications, including sequestration of nuclear waste.

Title: Investigating Disorder and Dynamics in MAS NMR using First-Principles Calculations.

Abstract:  Nuclear Magnetic Resonance (NMR) spectroscopy provides an element-specific probe of the local structure and dynamics in solids, without any requirement for long-range order.   Disorder can be modelled by substitution of atoms into a single unit cell or by creating a larger “super cell”. Calculation of the resulting NMR parameters can then be used to help interpret the complex spectra observed. Here, we demonstrate this approach in ⁸⁹Y (I = 1/2) NMR of Y₂(Sn,Ti)₂O₇ pyrochlore ceramics, materials with applications in the long-term storage of radioactive waste, and in ⁴⁵Sc (I = 7/2) NMR of perovskites, of interest as functional materials. We also demonstrate that such calculations can provide insight into the nature of disorder, i.e., whether static or dynamic, using ¹⁷O (I = 5/2) NMR of hydrated minerals.

Other invited speakers at the symposium addressed complementary theme, including:

·         Bruce Balcom – holds a prestigious Canada Research Chair in Magnetic Resonance Imaging and Materials, and his contribution is highly relevant to the petroleum research field.  His talk was entitled 'Pure Phase Encode Spin Echo MRI in Materials Imaging'. 

·         Rod Wasylishen – ¹H MRI methods for imaging fuel-cell membrane structure and function, hyperpolarized ¹²⁹Xe NMR for the characterization of surfaces of microporous and mesoporous materials, and investigations of unreceptive metal nuclei in inorganic materials.

As well as the oral sessions the symposium included a lively, well-attended poster session, where over 30 graduate students and post-doctoral fellows presented their recent research findings.