01.10.2020 - 30.09.2023 (3 years)

PhD project: Study and development of polar organometallic tools: towards the preparation and selective functionalization of heterocycles

Filled

The synthesis of (hetero)aromatic compounds is an omnipresent challenge for the organic chemist due to their multiple and varied applications. Indeed aromatic and heterocycle moieties are everywhere in day life, either in materials science, optics, electronics or biology. Thus, researches in organic synthesis methodologies are continually in progress for the preparation of heterocycles and their functionalization.

That is why, the aim of this PhD project is to develop original organometallic reagents to allow the development of innovative synthetic sequences for the preparation of highly functionalized (hetero)aromatic derivatives. In particular, we will focus our attention on bimetallic ate complexes as metalating reagents for metal-halogen exchange (MHE) or deprotonation. Their design, preparation and reactivity will be studied at first on heterocycle model and then exemplify to various heterocycles. Bimetallic ate complexes result in combining a polar organometallic (e.g. an organolithium) with a “soft” organometallic (organomagnesium for example), which the behaviour is different from those of the precursor. The principle is a synergy created by mixing two different organometallic reagents allowing increased selectivity and reactivity as well as use under non-cryogenic conditions compared to the monometallic reagent.

more details in the job offer desciption (file attached)

Sabrina Touchet - Contacter
Université de Lorraine
Laboratoire L2CM - UMR CNRS 7053
Faculté des Sciences et Technologiques
Boulevard des Aiguillettes - BP 70239
F-54506 Vandoeuvre-lès-Nancy

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du 01-10-2019 au 30-09-2022

PhD position: Photoactive Iron Complexes: Design and Application to Solar Energy

Filled

The aim of the thesis program is to develop photosensitive compounds from low-cost and environmentally friendly metal complexes. While ruthenium complexes have been widely studied and used in many laboratory applications because of their ideal photophysical properties, ruthenium is a rare, toxic and expensive metal, which limits real industrial development. Our project aims to replace this metal with other metals such as iron, which is strategic in the search for low-cost devices and industrial processes that conserve resources. In particular, we are targeting the development of photosensitizers for the manufacture of dye solar cells (DSSCs).

3 years

PhD: Semi-crystalline mesostructured axides as supports for catalysis

position filled

Contact by mail to apply or for any information:

PhD supervisor: Pr. Jean-Luc Blin, Laboratoire Lorrain de Chimie Moléculaire, jean-luc.blin@univ-lorraine.fr

& co-supervisor: Dr. Bénédicte Lebeau, Institut de Science des Matériaux de Mulhouse, benedicte.lebeau@uha.fr

Context: Transition metal oxides play an important role in industry as catalyst, catalyst support or to take advantage of their optical and electronic properties, such as luminescence. However, the compounds existing on the market suffer from their low specific surface (25 m2 / g for example for TiO2). Thus, the preparation of structured mesoporous materials which have a large specific surface area is an advantageous solution for better exploiting the inherent properties of transition metals oxides. A collaboration between the Laboratoire Lorrain de Chimie Moléculaire (L2CM) and the Institut de Science des Matériaux de Mulhouse (IS2M), has led to the synthesis of mesostructured titania with 2D hexagonal porous network, having semi-crystalline framework and with high specific surface area (> 250 m²/g). Our synthesis strategy combined EISA with the Liquid Crystal templating pathway. Pluronic P123, an amphiphilic triblock copolymer, is used as pore templating agent and titanium isopropoxide as inorganic precursor. The mesostructure is stable until 500°C. The surfactant is removed by different methods: calcination, flash induction or water extraction. The obtained mesostructured titania have also been used as supports to design of “CoMoS” hydrotreatment catalysts (co-activated MoS2) which were tested for the conversion of 4,6-dimethyldibenzothiophene (46DMDBT). This study has been performed in collaboration with the Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP). Obtained results, stand out from what has been reported in the past. Firstly, mesostructured titania present a high concentration of Brønsted acid sites on the surface. This is very unusual for TiO2, which is reputed to be non-acidic. Secondly, a shift towards DDS selectivity in the conversion of 46DMDBT, which is unprecedented in literature, was observed. This change in selectivity allows to consume less hydrogen and thus making the process more eco-friendly. These results show that the amorphous phase involves modifications of the support leading to significant modifications of the catalytic properties (HYD / DDS selectivity ratio), which offers unexplored possibilities in terms of catalyst development.

Goal : Our objective during the thesis is to deepen the mechanisms of formation of mesostructured transition metal oxides by studying in particular the influence of the presence of additives (salt, complexing agent, etc.) produced or added during the synthesis on the phase behavior of the surfactant in solution. We also aim to describe in a rational way the existing relationships between the structural and textural characteristics of the support (in particular the presence of the amorphous phase) and the activity and selectivity of the final catalysts. The catalytic reactions envisaged concern the hydrotreatment and in particular HDS or oxidation reactions such as for example the oxidation of toluene We are mainly interested in alumina and zirconia. The synthesis methodology will also be extended to MgO which plays an important role in catalysis.