PhD offer (MACO group) – Understanding radical reactivities with organometallic systems by an integrated experimental and computational approach

The MACO group is looking for a candidate for a PhD scholarship on the topic:

Understanding radical reactivities
with organometallic systems by an integrated experimental and computational approach

Project overview :  

Link on Adum

The catalytic machinery used by Nature is chemically impressive and based on the right balance between capturing the substrates to transform them and building non-covalent interactions to create the perfect conditions for performing reactions, through the help of evolution. Imitating and creating new catalytic machineries is thus a long-term goal, which will rely heavily on the understanding of precise interactions at work during the key steps of the catalytic events. A way to perform efficient catalytic events is to generate more reactive species like radicals in conjunction with metallic species, through photo-redox catalysis for instance.(1)

One of the key points to understand chemical reactivity is to analyse the interactions between the substrate and the catalytic center. What is the interplay between substrate and solvent molecules already present around the catalytic center? In the particular case of radical reactions, one of the key questions is related to the preference of radicals to interact with metals rather than coupling with another radical or doing a hydrogen abstraction.(2,3) To explore this philicity (4) of radicals towards metals, we envisage for example to compare the kinetics of radical addition on two metals (Ni (5) and Pd (6) ) involved in photo-redox catalysis. Another axis will be to understand how radicals interact with an organometallic, based on Pt or Au, activated by energy transfer,(7) and/or to apprehend the fate of radicals interacting with organometallic species in their excited states. The ultimate goal will be to determine if the philicity of radicals towards metals is determined by the nature of the metal or by some other external factors.

To answer these questions, we will rely on radical catalytic systems developed in the lab and study them from both a computational and an experimental point of view, in a teamwork manner with some members of the MACO group:

  • Select the most representative systems, and redesign them to be able to disentangle all key factors (solvent, counter-ions, co-catalyst, …)
  • Perform standardized experiments to retrieve key values: half-time of reaction, UV-Visible spectra during reaction course, precise ratio of products, identification of intermediates, … which will be used for cross-validation of computations in the next steps.
  • Building proper computational systems by integrating specific molecular architecture into classically used force fields; adding environmental effects (counter-ions, solvent, …). This task will be done for a selection of similar systems, by varying each structural parameters one by one for further testing.
  • Testing the validity of the simulation scheme previously developed by comparing the simulated data with experimental observables obtained by the various experimental spectroscopies.
  • Implementing the previously validated systems into a hybrid QM/MM scheme, in a straightforward manner (i.e., by scripting the human time-consuming steps) to render this task more affordable for later use with similar systems.
  • Calculating key elementary steps for various catalytic radical processes, taking into account all the environmental effects.
  • Integration of all the results (computational and experimental) to rationalize the behavior of radical in presence of (photo)organometallic catalytic systems.

To summarize, the main idea of this PhD program is to reach a better understanding of radical reactivities in the presence of organometallic species, by combining experiments and computational analysis.

Profiles : 

The candidate must hold a master’s degree in Chemistry, with a specialization in both organic chemistry and modeling. A strong interest in understanding reaction mechanisms and the use of computer tools will be a plus.

Level of English required: Advanced: You can speak the language in a more complex way, spontaneously and on a variety of subjects

Duration:

36 months from October 2024

Application:

– Send a cover letter
– a detailed CV
– with the name or addresses of minimum 1 referee

Contact : Etienne DERAT (e-Mail)

Keywords: 
radical chemistry , computational chemistry, organometallic, mechanism

References

1) Corcé, V.; Chamoreau, L.-M.; Derat, E.; Goddard, J.-P.; Ollivier, C.; Fensterbank, L. Silicates as Latent Alkyl Radical Precursors: Visible‐light Photocatalytic Oxidation of Hypervalent Bis‐catecholato Silicon Compounds. Angew. Chem. Int. Ed. 2015, 54, 11414–11418.

2) Gansäuer, A.; Bluhm, H. Reagent-Controlled Transition-Metal-Catalyzed Radical Reactions. Chem. Rev. 2000, 100, 2771–2788.

3) Studer, A.; Curran, D. P. Catalysis of Radical Reactions: A Radical Chemistry Perspective. Angew. Chem. Int. Ed. 2016, 55, 58–102.

4) Parsaee, F.; Senarathna, M. C.; Kannangara, P. B.; Alexander, S. N.; Arche, P. D. E.; Welin, E. R. Radical Philicity and Its Role in Selective Organic Transformations. Nat. Rev. Chem. 2021, 5, 486–499.

5) Jaouadi, K.; Abdellaoui, M.; Levernier, E.; Payard, P.-A.; Derat, E.; Le Saux, T.; Ollivier, C.; Torelli, S.; Jullien, L.; Plasson, R.; Fensterbank, L.; Grimaud, L. Regime Switch in the Dual-Catalyzed Coupling of Alkyl Silicates with Aryl Bromides. Chem. – Eur. Jour. 2023, e202301780.

6) Maestri, G.; Malacria, M.; Derat, E. Radical Pd (III)/Pd (I) Reductive Elimination in Palladium Sequences. Chemical Communications 2013, 49, 10424–10426.

7) Welin, E. R.; Le, C.; Arias-Rotondo, D. M.; McCusker, J. K.; MacMillan, D. W. C. Photosensitized, Energy Transfer-Mediated Organometallic Catalysis through Electronically Excited Nickel(II). Science 2017, 355, 380–385.