Sujet de stage / Master 2 Internship

Parahydrogen hyperpolarisation is a leading method to increase the sensitivity of Nuclear Magnetic Resonance. This method requires a catalyst which, in solution, impairs spectral resolution. The present internship consists in the synthesis of catalysts grafted onto silica and the relationship between their structures and their hyperpolarised NMR properties.

Nuclear magnetic resonance (NMR) is a powerful non-invasive analysis technique, ideal for characterising systems, in particular those that change over time. The robustness and quantitative nature of NMR provide valuable information about chemical reactions, which can then be better characterised and optimised. However, NMR is quite low sensitive, and low-concentration compounds, such as reaction intermediates, may be unobservable by conventional NMR.

One of the methods known to temporarily but drastically increase the sensitivity of NMR employs the particular properties of parahydrogen. The laboratory has developed a set-up for enriching dihydrogen in parahydrogen and has carried out methodological developments on its use in NMR [1]. The characteristic signals of certain molecules can be enhanced using a method called SABRE [2]. However, this technique requires the use of a catalyst whose NMR signals can mask signals from low-concentration compounds. By grafting the catalyst onto a nanoporous solid support, such as silica, it can be separated from the medium to be analysed and only the compounds in solution give observable signals.

The M2 research project aims at exploring the grafting of the catalyst onto different silicas, in different proportions, and to characterise the increase in NMR signals from solutes. Initially, stable solutions will be analysed and then, if possible, a chemical reaction will be monitored, in which a reactant and/or product is likely to be observed by the SABRE method.
Applications (CV and covering letter) should be sent to stephane.campidelli@cea.fr and gaspard.huber@cea.fr by 31 October 2023.

References:
[1] Guduff et al. Single-Scan Diffusion-Ordered NMR Spectroscopy of SABRE-Hyperpolarized Mixtures. ChemPhysChem 2019, 20, 392-398.
[2] Sellies et al. Parahydrogen induced hyperpolarization provides a tool for NMR metabolomics at nanomolar concentrations. ChemComm 2019, 55, 7235-7238.