Catalytic properties and dynamic behaviour of uranium complexes
Description
The catalytic properties of organometallic uranium III and IV compounds in solution as well as reaction mechanisms are studied. The structure in solution of CpUCl3L2 (L=THF, HMPA, OPPh3, OP(OR)3) is investigated. When L=HMPA, the complex exists in two isomers in equilibrium with the L ligands either in trans or mer-cis configuration. The isomerization (Ea=92 kJ mol-1) as well as the bimolecular exchange with an outer sphere ligand L are observable in 1H and 31P NMR, and quantified with the spin saturation transfer technique in several solvents and at different temperatures between 230 and 330 K. This property is extended to other ligands. The compound U(AlH4)3 is synthetized. This compound catalyses the hydroalumination of olefins by LiAlH4 with a very good anti-Markovnikov regioselectivity. A simple mechanism for this reaction is suggested. The reactions of the organoaluminates products with several reactants (D2O, I2, CH2O, Allyl-Br...) has been shown to be a powerful synthetic tool. Some specific alkenes and alkynes exhibit an interesting behaviour as dimerization or β-alkyl elimination which is easily interpreted by our mechanism.
Abstract (French)
Nous etudions les proprietes catalytiques de composes organometalliques de l'uranium en solution ainsi que certains mecanismes reactionnels qui regissent la sphere de coordination du metal aux degres d'oxydation III et IV. Nos investigations portent sur l'etude structurale en solution de composes de la forme CpUCl3L2 ou L est un ligand neutre monodentale (THF, HMPA, OPPh3, OP(OR)3). Nous monrons dans le cas L=HMPA que le complexe existe sous deux formes en equilibre ou les ligands L sont soit en trans, soit en mer-cis. Seule cette derniere forme etait connue a l'etat solide. L'isomerisation ainsi que l'echange (bimoleculaire) avec un ligand L rajoute en solution sont observables en RMN (1H et 31P) et quantifies grace a la saturation par transfert de spin dans differents solvants entre 230 et 330 K. Ces proprietes sont generalisees aux autres ligands. Nous prouvons l'existence du compose U(AlH4)3 et mettons en evidence qu'il catalyse l'hydroalumination d'alcenes directement par LiAlH4 avec une excellente regioselectivite de type anti-Markovnikov. Nous proposons un mecanisme simple pour cette reaction. La reaction des composes alkylaluminates ainsi formes avec des reactifs simples (D2O, I2, CH2O, Allyl-Br...) s'est revelee etre un outil synthetique puissant, jusque la peu developpe. Quelques substituants particuliers (alcynes ou alcenes aromatiques) presentent un comportement singulier (dimerisation, β-alkyl elimination) qui s'interprete bien avec notre mecanisme. (auteur)Files
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Additional details
Additional titles
- Original title (French)
- Proprietes catalytiques et comportement dynamique de complexes de l'uranium
Publishing Information
- Imprint Pagination
- 202 p.
- Report number
- FRCEA-TH--20
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 53024553
- Subject category
- S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- ALKENES; ALUMINIUM COMPOUNDS; CATALYSIS; CATALYSTS; CHEMICAL REACTION KINETICS; HYDRIDES; ISOMERS; LIGANDS; ORGANOMETALLIC COMPOUNDS; REDUCTION; SYNTHESIS; URANIUM COMPLEXES
- Descriptors DEC
- ACTINIDE COMPLEXES; CHEMICAL REACTIONS; COMPLEXES; HYDROCARBONS; HYDROGEN COMPOUNDS; KINETICS; ORGANIC COMPOUNDS; REACTION KINETICS
Optional Information
- Notes
- Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses; This record replaces 19031061