Post-doctoral fellow in Physical Chemistry for the development of molecular photocatalysts based on N-heterocyclic carbenes for the photoreduction of organic substrates (M/F)

Job Description

Missions

Photoredox catalysis offers innovative solutions in organic synthesis for the reductive activation of inert substrates under mild conditions [Chem. Rev. 2013, 113, 5322 ; Chem. Rev. 2016, 116, 10075]. However, conventional photocatalysts are limited by the reducing power of their excited states (generally higher than –2 V vs ECS). The ANR CASPI project, which will host the future postdoctoral researcher, is exploring an approach based on the ConPET (Consecutive Photoinduced Electron Transfer) mechanism, aimed at generating anionic photocatalysts with high reducing power from N-heterocyclic carbene (NHC) compounds. These NHC organocatalysts, recently employed in various reductive radical transformations [Angew. Chem. Int. Ed. 2021, 60, 26783 ; Chem. Sci. 2024, 15, 14699], could see their reactivity extended to hard-to-reduce substrates—which have hitherto been inaccessible—through visible-light irradiation, as suggested by our preliminary results. The postdoctoral researcher's work will therefore aim to design and study new NHC-based organophotocatalysts to promote the reduction of organic substrates known to be difficult to reduce, such as aryl halides.

Activity

The candidate will be responsible for investigating the redox properties (using molecular electrochemistry) and photophysical properties (using steady-state and time-resolved absorption and emission spectroscopy) of these new organophotocatalysts and their reaction intermediates involved in the catalytic process. These studies will be carried out at the Department of Molecular Chemistry (DCM) at the University of Grenoble Alpes under the supervision of Dr Jérôme Fortage (EMPRe Group). The synthesis of the new organophotocatalysts and their characterisation (NMR, mass spectrometry, X-ray crystallography, etc.) will be carried out by a PhD student also recruited to the DCM and supervised by Dr David Martin (CIRe Group). The investigation of their photocatalytic properties (under light irradiation in the presence of organic substrates) will be carried out by a second PhD student recruited at the Institute of Radical Chemistry at Aix-Marseille University under the supervision of Dr Julie Broggi.

Your Profil

Skills

The candidate must be a molecular chemist. Experience in molecular electrochemistry or photochemistry (or even photocatalysis) would be an advantage (but is not essential). The candidate should be meticulous, creative, highly motivated and hard-working. They must be able to work as part of a team but also independently with minimal supervision. The candidate must be fluent in French or English.

Your Work Environment

This research project is funded by the French National Research Agency (ANR) under the acronym CASPI and will be carried out as part of a collaboration between the Department of Molecular Chemistry (UMR 5250) at the University of Grenoble Alpes, within the Molecular Electrochemistry and Redox Photochemistry (EMPRe, Dr Jérôme Fortage) and the Inorganic Redox Chemistry team (CIRe, Dr David Martin), and the Institute of Radical Chemistry (UMR 7273) at Aix-Marseille University within the Radical Pharmacochemistry team (PCR, Dr Julie Broggi). The CASPI project aims to rationally design highly reductive processes through the direct photoactivation of organocatalytic intermediates by N-heterocyclic carbene (NHC) species, which are themselves already highly reductive. The proposal is based on emerging concepts (for example, 'ConPET': Consecutive Photo-induced Electron Transfer) in which an initial transformation of a photocatalyst produces an anionic radical, which, in turn, can photo-induce extreme reductions, as well as on original preliminary results published by the CIRe and PCR teams [Angew. Chem. Int. Ed. 2021, 60, 26783 ; Chem. Sci. 2024, 15, 14699]. Radical organocatalysis using NHCs and extreme reductive photocatalysis are highly competitive fields of research. Most international teams focus primarily on the methodological optimisation of 'black boxes' and remain constrained by the difficulty of studying key transient intermediates and complex photophysical and/or mechanistic scenarios. In contrast, CASPI draws on the consortium's experience in handling, studying and understanding reactive intermediates derived from NHCs to propose a rational approach. The consortium intends to i) develop NHC models that promote redox activity, the stability of radical forms and strong absorption in the visible spectrum; ii) to carry out a comprehensive photoelectrochemical study and evaluate the photoreactivity of the main key intermediates; iii) on this basis, to design powerful NHC-photocatalysed reactions that remain selective, whilst involving highly reductive activations (such as 'Birch'-type reactions, for example).
The “Département de Chimie Moléculaire” (DCM), within which the postdoctoral researcher will work, is a joint CNRS/Université Grenoble Alpes unit (UMR 5250) comprising nearly 80 permanent researchers, lecturers, ITA and IATOSS staff, and an equal number of PhD students, postdoctoral researchers and Master's students, centred around two interrelated research areas: chemistry for health and chemistry for nanosciences. Furthermore, the DCM is organised into six research teams, each focusing on a specific scientific theme, notably the EMPRe team, which possesses strong expertise in molecular electrochemistry and redox photochemistry. The EMPRe team possesses particular expertise in the field of photo- and electrocatalysis dedicated to the reduction of CO₂ and protons to H₂, and more broadly to the dissociation of water into O₂ and H₂, as well as in the electrochemical and photophysical characterisation of photo- and electro-induced catalytic processes. The EMPRe team also has all the electrochemical and photophysical instrumentation required to carry out this research. The successful candidate will work within the EMPRe group under the supervision of Dr Jérôme Fortage (CRCN CNRS).

Constraints and risks

The candidate will be required to handle organic solutions containing low-toxicity chemicals. He or she will regularly use Class 4 lasers as part of photophysical studies and high-power Xe lamps (light intensity of around 100 mW/cm²) as part of research into photocatalytic mechanisms.

Compensation and benefits

Compensation

Starting at €3,041 gross per month, depending on experience

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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