A star-product approach to noncompact quantum groups

Using duality and topological theory of well behaved Hopf algebras (as defined in [2]) we construct star-product models of non compact quantum groups from Drinfeld and Reshetikhin standard deformations of enveloping Hopf algebras of simple Lie algebras. Our star-products act not only on coefficient functions of finite-dimensional representations, but actually on all $C^\infty$ functions, and they exist even for non linear (semi-simple) Lie groups.Comment: 13 page

Le droit du recouvrement en ses aspects notariaux

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Les moyens de se prémunir contre la défaillance de ses cocontractants

peer reviewedaudience: researcher, professional, studentCette contribution commentait l'impact de la réforme de 1997 du droit de l'insolvabilité sur les droits des créancier

Metal-free reduction of CO2

Even if carbon dioxide is now considered a major pollutant and the main source of global warming, it remains the feedstock used by Nature to generate organic compounds. There is considerable interest to find chemical processes that could replace fossil fuels by CO2 to generate industrially relevant carbon containing molecules. Mostly relying on frustrated Lewis pair technology and on the nucleophilic activation of CO2 or reducing agents by organic Lewis bases, novel catalytic opportunities have emerged to affect the metal-free catalytic reduction of carbon dioxide

On the concept of frustrated Lewis pairs

In this concept article, we consider the notion of ‘frustrated Lewis pairs’ (FLPs). While the original use of the term referred to steric inhibition of dative bond formation in a Lewis pair, work in the intervening decade demonstrates the limitation of this simplistic view. Analogies to known transition metal chemistry and the applications in other areas of chemistry are considered. In the light of these findings, we present reflections on the criteria for a definition of the term ‘frustrated Lewis pair’. Segregation of the Lewis acid and base and the kinetic nature of FLP reactivity are discussed. We are led to the conclusion that, while an all-inclusive definition of FLP is challenging, the notion of ‘FLP chemistry’ is more readily recognized

Coordination of ethylene to a zwitterionic Rh(III) half-sandwich complex : influence of ambiphilic Ligands on reactivity

The reactivity of Rh(III) half-sandwich complex Cp*RhMe2(κ P -μ Al-MePMe2CH2AlMe2) 2 (Cp* = η 5 - pentamethylcyclopentadienyl) with ethylene was investigated. Coordination of ethylene (or ethylene-d4) gave a mixture of products including as principal species zwitterionic complexes Cp*Rh+Me(C2H4)(PMe2CH2AlMe3 - ) 4 (or 4-d4) and [Cp*Rh+Me(C2H4)(PMe2CH2AlMe3 - )][AlMe3] (4’), after the abstraction of a Rh-methyl group by the pendant Lewis acid, and base free Cp*RhMe2(PMe2CH2AlMe2) (5). Heating this complex at 50 °C results in the generation of propene (or propene-d3,4), methane (or methane-d1), and trace amounts of butene, as organic materials, as well as previously characterized [Cp*RhMe(μ 2 -η 2 (P,C)-PMe2CH2)]2 (10) and rhodium(I) species. Two different pathways for the reactivity of the zwitterionic π-complex were investigated by density functional theory (DFT). It is likely that propene is formed by β-hydride elimination from a cationic Rh-propyl fragment that is generated either by insertion of ethylene into a Rh-C bond or by a nucleophilic attack of the methyl-aluminate fragment on coordinated ethylene. After releasing propene, the neutral complex Cp*RhHMe(PMe2CH2AlMe2) 11 is most likely responsible for the reductive elimination of methane

Couplage de codes éléments finis et dynamique discrète de dislocations

National audienceLe calcul couplé entre la méthode des éléments finis et la dynamique discrète de dislocations est utilisé pour simuler le comportement cyclique d'un agrégat polycristallin. La convergence et la validation du couplage sont discutées