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Reference : UPR8241-ANTSIM-004
Workplace : TOULOUSE
Date of publication : Friday, April 10, 2020
Scientific Responsible name : Antoine Simonneau
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2020
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
The transformation of N2 into more reactive nitrogen sources has been intensely studied by chemists for over a century. Beyond the scientific challenge represented by the activation of this abundant but inert molecule, research efforts on nitrogen fixation are intimately linked to the needs of agriculture in nitrogen fertilizers. The industrial Haber-Bosch (HB) process currently allows the production, from N2 and H2, of millions of tons of ammonia (NH3), of which ¾ are used to manufacture fertilizers. Although efficient, the HB process remains highly demanding in fossil resources and energy (1 to 2% of world energy). In addition, this production of NH3 is accompanied by significant CO2 emissions. Finding a greener alternative to the Haber-Bosch process is therefore a challenge that modern chemistry must meet. In this perspective, the use of dinitrogen molecular complexes is promising, as shown by recent successes in the development of catalytic reactions for reducing dinitrogen to ammonia under mild conditions, with however numerous drawbacks such as the use of expensive and unsustainable reducing agents; the challenge of catalytically reducing N2 with H2 under homogeneous conditions remains to be overcome. Our team is developing cooperative dinitrogen activation methods by combining an abundant, non-toxic transition metal (Mo or W) and boron-based Lewis acids. We have recently discovered that such combinations are also capable of activating, simultaneously with N2, the dihydrogen molecule to form metal hydrides. We propose to the student to carry out a systematic study of the activation of H2 by our dinitrogen complexes by varying in particular the metal, its coordination sphere and the Lewis acid (LA). In this last line of study, preliminary results tell us that the activation of H2 in systems incorporating a cationic boron Lewis acid differs radically from those based on neutral boron species. On the basis of these preliminary results, the thesis project will aim to better define the parameters to be adjusted to successfully hydrogenate dinitrogen under mild conditions, and study the reactivity of the N2-hydride complexes.
The doctorate will be carried out at the Laboratory for Coordination Chemistry (LCC, http://www.lcc-toulouse.fr/), which is one of the leading French institutes in chemistry. We have at our disposal very well-equipped technical and analytical platforms for the daily support of scientific work. With a stimulating work environment with more than 70 researchers and 100 student-interns, doctoral and post-doctoral students of different nationalities divided into 15 teams, research at the LCC places coordination chemistry as a central tool for tackling current challenges related to climate change, energy transition and life sciences. The recruiting SMAc (Small Molecule Activation) team is led by Drs. S. Bontemps and A. Simonneau. The Ph. D. will be supervised by the latter.
This Ph. D. is funded by a "starting Grant" of the European Research Council. The candidate must have a Master degree in chemistry or equivalent. Solid knowledge in general and molecular chemistry is essential. A background in organometallic chemistry and coordination, and the experimental skills associated with it (working in a glove box, vacuum line, Schlenk techniques) is undeniably a plus. More generally, the candidate must be able to conduct research in an academic environment, for example preparing, setting up, carrying out an experiment and analyzing the results, and seeking and knowing the scientific literature associated with it; he·she must be able to organize her own research activities according to the agreed deadlines and requirements. Excellent computer skills (using word processing, spreadsheet and presentation software) are essential. He·she must have excellent written and oral communication skills in both English and French, to effectively support the production of research reports and publications, or to enable effective presentation of progress and results research to supervisors and colleagues. It is essential that the candidate can effectively communicate new and complex information to a wide range of audiences, know how to work in a team but also independently on his own initiative, and demonstrate curiosity. In contact with our team, and over the course of three years of thesis, he·she will strengthen his·her laboratory autonomy and his·her critical mind, and will acquire solid skills in synthesis, manipulation and characterization of sensitive complexes.
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