Understanding the structure and dynamics of materials at both the atomic and molecular levels is one of the major scientific challenges in material science. Amongst the various techniques of characterisation, solid-state NMR has become one of the most advanced and efficient methods, thanks to the numerous methodological and technological improvements associated with it. Today, the methodological developments in solid-state NMR are making it possible to acquire high-resolution spectra, even for quadrupolar nuclei of low natural abundance (i.e. oxygen-17). Furthermore, it is possible to correlate through space and through the chemical bond, the local environment of a nucleus. In the present work, we report on the use of 17O MAS NMR as a spectroscopic tool to probe the local environment of complex inorganic materials of interest in various domains of applications. Using high magnetic field, we will first show that 17O MAS NMR spectra can nowadays be obtained at natural abundance to check the validity or violation of the Lowenstein’s rule in a series of synthetic layered silicates. The use of specific pulse sequences to increase signal to noise ratio, such as DFS or HS, will also be assessed in the case where both quadrupolar and chemical shift anisotropy couplings are non negligible. This will be illustrated through the characterisation of molecular complexes and supported organometallic species encountered at different stages of a catalyst development. Finally, a combination of 17O NMR experiments (1D MAS and 2D MQ MAS and D-HMQC) are used as a novel tool to retrieve information about the configuration, the grafting mode or the interaction of metal centres with the support.

Advanced 17O MAS NMR methods to characterise the local environment in complex inorganic systems

253rd National Meeting (2017)

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