25-30 August 2019
Henry Ford Building
Europe/Berlin timezone

Defects within Solid Materials Elucidated using NMR Spectroscopy – from Local Vacancies to Mesoscale Disorder

27 Aug 2019, 10:30
35m
Lecture Hall C (Henry Ford Building)

Lecture Hall C

Henry Ford Building

Invited talk Materials applications Materials

Speaker

Prof. Juergen Senker (University of Bayreuth)

Description

Structure-property relations are essential for designing materials. As many properties are governed by defects and disorder, respectively, elucidating structural details on various length scales is a cornerstone for material science and solid-state chemistry. This lecture will give an overview of our recent progress on using solid-state NMR spectroscopic techniques for studying defects and disorder. Hereby, we will show, that NMR aids the structure elucidation process for materials as diverse as high-pressure minerals, frameworks and supramolecular self-assemblies. It provides central information from local to intermediate length scales by exploiting chemical shifts, connectivities, distances and orientation correlations based on homo- and heteronuclear correlation experiments. NMR spectroscopy is at its best, when used quantitatively as a cost function in addition to scattering and quantum mechanical calculations [1 - 3].
We will report on the incorporation of water in anhydrous ringwoodite by formation of various hydroxyl defects [2, 3]. Here the quantitative analysis of 1H 1D and 2D DQ NMR spectra allowed for unravelling a surprisingly rich defect chemistry. In contrast, the key to a deeper understanding of substitution defects within Bridgmanite was an unambiguous assignment of the 27Al MAS NMR spectra based on STMAS experiments. Finally, to derive a mechanistic picture for the supramolecular self-assembly of benzene trisamides (BTAs) [4] and the role of the resulting nanoobjects within the foaming process of polypropylene, multinuclear (1H, 13C, 15N and 19F) and multidimensional NMR experiments were carried out. DNP was essential to allow for studying the BTA polymer mixtures down to concentrations of a few hundred ppm.

[1] H. Grüninger, et. al. J. Am. Chem. Soc. 2017, 139, 10499.
[2] H. Grüninger, et al. Phys. Chem. Chem. Phys. 2018, 20, 15098.
[3] C. S. Zehe, et al., Angew. Chem. Int. Ed., 2017, 56, 4432.

Primary authors

Prof. Juergen Senker (University of Bayreuth) Dr Christoph Zehe (University of Bayreuth) Mr Kasper van der Zwan (University of Bayreuth) Dr Renée Siegel (Anorganische Chemie III, University of Bayreuth) Dr Gaël De Paëpe (CEA Grenoble) Dr Klaus Kreger (University of Bayreuth) Prof. Hans-Werner Schmidt (University of Bayreuth)

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