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Conférence WELLER & KORTZ

Le 9 décembre 2021
À 16h30
Salle des Séminaires de la Faculté de chimie

 

Conférence-Symposium de Chimie des Métaux de Transition

 Prof. Dr A. WELLER (Univ. York) & Prof. Dr U. KORTZ (Jakobs Univ.)

 

Jeudi 9 décembre 2021

à partir de 16:30

 

Salle des Séminaires de la Faculté de chimie de l'Université de Strasbourg (Campus Esplanade).

 A. Weller et U. Kortz sont tous deux professeurs invités de la Faculté de Chimie.

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Reactivity and Dynamic Processes in Solid State Organometallic Chemistry: Who Needs a Solvent?

 

Andrew WELLER

Department of Chemistry,
University of York,
Heslington, York, YO10 5DD, UK

Organometallic synthesis, reactivity and catalysis is traditionally performed in the solution–phase. Although such homogeneous chemistry allows for highly reactive, selective and precisely tuneable organometallic systems, it has its limitations when solvent reacts deleteriously with the desired metal complex, very cold temperatures are required for synthesis (below the freezing point of any suitable solvent) or the lifetime of the targeted complex is shorter than the timescale for analysis (for example growing crystals for single–crystal x-ray diffraction). While heterogeneous systems offer less well–defined active–sites, the microenvironment of the catalyst, or its platform support, can be important in helping control selectivity or catalyst stability. 
In this contribution the development in our laboratories of Solid–State Molecular Organometallic (SMOM) chemistry and catalysis is presented, in which molecular organometallic complexes are synthesised in the solid–state by single–crystal to single–crystal transformations. The non–covalent interactions in the solid–state microenvironment around the metal prove to be crucial in both directing the course of reaction, and stabilising highly reactive complexes, some of which are essentially impossible to prepare by solution–based routes. The synthesis of a variety of sigma–alkane complexes, and the subsequent C–H activation processes they undergo, will be used to highlight the benefits of this technique in organometallic chemistry and catalysis.

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Recent Developments in Peroxo-Polyoxometalate Chemistry

Ulrich KORTZ

Department of Life Sciences and Chemistry,
Jacobs University,
Campus Ring 1, 28759 Bremen, Germany

Email: u.kortz@jacobs-university.de
http://ukortz.user.jacobs-university.de

Polyoxometalates (POM) are discrete, anionic metal-oxo clusters with a wide range of
interesting physicochemical properties.1 Lanthanide- and actinide-containing POMs
represent a well-known subclass, which is of interest due to many large to very large
structures combined with interesting magnetic and photochemical properties.2 The
number of lanthanide-containing POMs is significantly larger than those incorporating
actinide ions. Nevertheless, a couple of uranium-containing heteropolytungstates are
known and this field was pioneered by Pope’s group.2b,3 A peroxo-uranyl POM was also
reported, {(UO2)8P8W36},3b as well as peroxo-uranium spheres resembling buckyballs,
e.g. [{UO2(O2)(OH)}60]60-.3c Last year the first peroxo-cerium-containing POM was
reported, [CeIV6(O2)9(GeW10O37)3]24−, which is solution-stable and a recyclable
homogeneous catalyst for the selective oxidation of organic substrates.4 Very recently we
have prepared some novel peroxo-POMs of lanthanides, actinides,5 as well as zirconium
and hafnium, and some of them exhibit interesting catalytic properties.

1. Pope, M. T. Heteropoly and Isopoly Oxometalates; Springer, Berlin, 1983.
2. (a) Bassil, B. S.; Kortz, U. Z. Anorg. Allg. Chem. 2010, 636, 2222; (b) Pope, M. T.
Handbook on the Physics and Chemistry of Rare Earths, 2008, 38, 337.
3. (a) Dufaye, M.; Duval, S.; Stoclet, G.; Trivelli, X.; Huvé, M.; Moissette, A.; Loiseau,
T. Inorg. Chem. 2019, 58, 1091; (b) Mal, S. S.; Dickman, M. H.; Kortz, U. Chem.
Eur. J. 2008, 14, 9851; (c) Sigmon, G. E.; Unruh, D. K.; Ling, J.; Weaver, B.; Ward,
M.; Pressprich, L.; Simonetti, A.; Burns, P. C. Angew. Chem. Int. Ed. 2009, 48,
2737.
4. Qasim, H. M.; Ayass, W. W.; Donfack, P.; Mougharbel, A. S.; Bhattacharya, S.;
Nisar, T.; Balster, T.; Solé-Daura, A.; Römer, I.; Goura, J.; Materny, A.; Wagner,
V.; Poblet, J. M.; Bassil, B. S.; Kortz, U. Inorg. Chem. 2019, 58, 11300.
5. Goura, J.; Sundar, A.; Bassil, B. S.; Ćirić-Marjanović, G.; Bajuk-Bogdanović, D.;
Kortz, U. Inorg. Chem. 2020, 59, 16789.