PhD thesis in organometallic chemistry and molecular catalysis (M/F)

Job Description

Thesis Subject

Synthetic organometallic chemistry and homogeneous catalysis: Defluorination of PFAs with alkaline-earth catalysis

The direct and indirect toxicity of poly- and perfluoroalkyl substances (PFAS) towards health and the environment is well established. These "perennial pollutants" are a source of alarming concern and regularly make headlines in both mainstream press and specialized scientific journals. A comprehensive remediation strategy is essential to address the PFAS problem. This catalytic engineering project applied to PFAS removal falls within this context. Although its relevance is acknowledged, the chemical modification of PFAS remains a relatively unexplored remediation tool. PFAS are robust and chemically inert due to their composition, which is rich in very strong C–F bonds. This project proposes an innovative approach based on sustainable chemistry. We will develop new molecular catalysts based on abundant, inexpensive, and non-toxic alkaline earth metals (calcium and strontium) that will enable the hydrodefluorination of PFAS, i.e., the replacement of C–F bonds with weaker C–H bonds. This modification will ultimately allow us to functionalize PFAS and remove them from contaminated environments. This project draws on the expertise of the host team at the Institute of Chemical Sciences of Rennes. It consists of successive stages ranging from the design and synthesis of the catalysts, to the optimization of stoichiometric reactions with model substrates, and finally, to the extrapolation of hydrodefluorination with PFAS to homogeneous catalysis. Furthermore, these tools are also relevant for the treatment and disposal of freons, these refrigerating gases that accumulate in the atmosphere, deplete the ozone layer, and contribute significantly to global warming. In fact, the catalytic systems developed for PFAS can and will also be used for gases such as trifluoromethane (R-23 Freon).

The project based on catalytic engineering relies on the use of calcium and strontium complexes, two metals with a unique affinity for fluoride ions, to catalyse the hydrodefluorination of PFAS, that is, their gradual breakdown through the replacement of strong C–F bonds with weak C–H bonds. The project is divided into four stages:
- Synthesis of alkaline earth complexes
- Stoichiometric reactions
- Catalytic hydrodefluorination cycles
- Hydrodefluorination of PFAS

This position requires strong affinities for in organometallic chemistry, homogeneous catalysis, and theoretical calculations (quantum chemistry).

Your Work Environment

The work will be conducted at the Institut des Sciences Chimiques de Rennes (UMR CNRS 6226), on the Beaulieu campus, at the University of Rennes. ISCR is one of the largest chemistry institutes in France, with approximately 600 members, including nearly 250 permanent staff.

The host group, led by Yann Sarazin (OCP: Organometallics for Catalysis and Polymers; 5 permanent members), is part of the "Organometallics: Materials and Catalysis" team (approximately 50 permanent members), which specialises in catalytic engineering, sustainable catalysis, the development of ecological alternatives, sustainable materials, and green chemistry.

The experimental work will primarily be conducted at ISCR, which possesses the necessary synthetic and analytical equipment and tools (300-600 MHz NMR spectrometers, diffractometers, mass spectrometers, elemental analysers, etc.) for the proposed research. The host laboratory is fully equipped for organometallic chemistry under an inert atmosphere. However, external collaborations may be beneficial for certain specific aspects, and short-term research trips (1-5 weeks) to Rouen and Mulhouse may be required as part of the project.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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