PhD Studentship: Bio-Inorganic Chemistry: Bioinspired Polymetallic Sulfide Clusters for Advanced El
Expected candidate background:
We are looking for a self-motivated candidate with a strong interest in molecular chemistry and electrochemistry. The candidate should have a solid background in coordination chemistry and synthetic molecular chemistry (organic/inorganic). He/she must demonstrate a good knowledge of the usual spectroscopic and electrochemical analytical methods.
Bioinorganic chemistry and electrocatalysis
Ecole Doctorale de Chimie et Sciences du Vivant (EDCSV), Université Grenoble Alpes, France
PhD supervisor Vincent ARTERO
Mentor Matthieu KOEPF
Expected starting date: October 2018
The development of sustainable alternatives to energy-intensive industrial processes represents a major challenge for the coming decades. In that context, exploring solar-driven approaches for the production of basic chemicals and fuels is particularly appealing.1 It will require to shift paradigm from thermally- to electro-driven processes, which are directly relevant to solar-driven approaches, and thus, must be associated with the development of innovative catalytic materials. Over the past years, the SolHyCat group has built a strong expertise in the design, synthesis and study of bioinspired protons2-5 and carbon dioxide6, 7 reduction electrocatalysts. Some of which could successfully be integrated into functional photocatalytic devices.8 We are now seeking to expand the scope of active electrocatalysts for multielectronic reactions available in the group. This PhD will be dedicated to the investigation of the reactivity of discrete synthetic polymetallic sulfide clusters towards industrially-relevant substrates (H+, H2, N2). The main goal will be to probe the ability of bioinspired polymetallic sulfides assemblies to activate dinitrogen under ambient conditions.
Electro-reduction of dinitrogen to ammonia is a highly demanding process requiring the transfer of 6 electrons and 6 protons to dinitrogen. Few catalysts are known for this reaction, most of which are based on noble metals (Pt, Pd, Ru) or mixed samarium oxides, and require high temperature and pressure to be effective.9 In stark contrast, naturally occurring nitrogenases catalyze the reduction of dinitrogen to ammonia, under physiological conditions, using discrete organometallic cofactors based on earth-abundant transition metal sulfides.10 The activity of these enzymes for dinitrogen reduction is remarkable, and has sparked the study of related polymetallic sulfide-based materials for multieletronic reduction catalysis. Remarkably, the inclusion of synthetic Fe4S4 and Fe6S7Mo2 motifs within inorganic matrices led to materials able to catalyze the reduction of N2 to ammonia.11,12 Due to the amorphous nature of the latter, however, the rationalization and fine tuning of the reactivity of the system remains challenging.
With this project, we will prepare well-defined ligand-supported iron- and molybdenum-sulfide clusters inspired from the active site of the nitrogenases. We will study their reactivity towards dinitrogen and protons. The use of polypyrrole-based ligands will be introduced as versatile synthetic platforms to design a new class of thiolated cavitands. The successful synthesis of discrete ligand-supported sulfide clusters will offer an unprecedented opportunity to study subtle structure-activity relationships in a new class bioinspired molecular materials and rationally tailor the catalysts for nitrogen reduction.
Ligands synthesis and characterization (year 1). The first objective will be to synthesize ligands possessing thiolated cavities (cavitands) around polypyrrolic platforms. Thiolated substituents will be grafted at the periphery of adequately substituted macrocycles via a) classical peptide coupling strategy, or b) 1,3-dipolar cycloaddition to build rigid thiolated substituents. The versatility of these two approaches will allow the introduction of a variety of substituents to form the cavity, and will offer the unique possibility to fine-tune both the first and second coordination sphere of the clusters.
Assembly of the polymetallic sulfide clusters (year 1+2). The stabilization of the clusters within the cavitands will be the second objective of this project. First we will investigate the stabilization of preformed iron- and molybdenum- sulfur clusters within the cavities of the ligands, by direct thiol exchange. In a second approach, the ligand-assisted assembly of iron-sulfur clusters, from molecular precursors, will be tested.
Electrochemical activation of the supported clusters (Year 2+3). The final objective of this PhD will be to explore the potential of the obtained clusters for driving the electrocatalytic reduction of selected substrates. The reactivity of the isolated cavitands-supported sulfide clusters will be investigated in the presence of relevant substrates (H+, N2) under reductive conditions. The systems will be tested in homogeneous conditions, or after immobilization of the supported clusters on Multiwall Carbon Nanotube (MWCNTs) electrodes.
This position will be funded by the Commissariat à l’Énergie Nucléaire et aux Énergies Alternatives (CEA) for 3 years, starting in october 2018. The gross monthly salary will be ca. 2000 euros for the first two years and ca. 2100 euros the third year. The student will benefit of a total of 51 days of vacation per year.
The Laboratoire de Chimie et Biologie des Métaux is part of the Biosciences and Biotechnology Institute of Grenoble (BIG) which is affiliated to the Direction de la Recherche Fondamentale of the CEA. The student will join the newly created SolHyCat team (team leader Vincent Artero), which will offer a stimulating international working environment. Please visit our website for further information:
Matthieu Koepf (email@example.com)
This project will initiate a brand new line of research in our lab!
1. Solar-Driven Chemistry 978-2-9601 655-2-4, European Chemical Sciences, Belgium, 2016.
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3. E. S. Andreiadis, P.-A. Jacques, P. D. Tran, A. Leyris, M. Chavarot-Kerlidou, B. Jousselme, M. Matheron, J. Pécaut, S. Palacin, M. Fontecave and V. Artero, Nat. Chem., 2013, 5, 48-53.
4. D. Brazzolotto, M. Gennari, N. Queyriaux, T. R. Simmons, J. Pécaut, S. Demeshko, F. Meyer, M. Orio, V. Artero and C. Duboc, Nat. Chem., 2016, 8, 1054-1060.
5. P. D. Tran, T. V. Tran, M. Orio, S. Torelli, Q. D. Truong, K. Nayuki, Y. Sasaki, S. Y. Chiam, R. Yi, I. Honma, J. Barber and V. Artero, Nat. Mater., 2016, 15, 640-646.
6. N. Elgrishi, M. B. Chambers, V. Artero and M. Fontecave, Physi. Chem. Chem. Phys., 2014, 16, 13635-13644.
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8. N. Kaeffer, J. Massin, C. Lebrun, O. Renault, M. Chavarot-Kerlidou and V. Artero, J. Am. Chem. Soc., 2016, 138, 12308-12311.
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