sophiecarenco

We propose the concept of a NanoFLP in a colloidal solution where one partner is a phosphine Lewis base and the other is the Lewis acid surface of a NiCo nanoparticle. We attempt to apply this concept to the hydrosilylative reduction of benzaldehyde. We identify a correlation between the Tolman cone angle and the silane conversion, consistent with both mechanisms; however, we found no clear correlation between the Tolman electronic parameter and the reaction outcome. Structural analyses evidenced that the nanoparticles are not altered during the reaction, which led us to propose the formation of a NanoFLP as a transient species in solution.

A. Palazzolo, S. Carenco. Chem. Mater. 2021, acs.chemmater.1c03105.

X-ray absorption near-edge structure (XANES) is a particularly well-adapted technique to study the L_2,3-edges of Mo (2520–2625 eV). It provides information on both the electronic and local structures of metal-containing species and allows drawing structure–activity relationships. However, L_2,3-edges are difficult to interpret, especially for 4d and 5d transition metals. In this work, we provide a method for their interpretation based on a library of spectra of simple Mo compounds. We suggest using the L₃-edge to determine the oxidation state and the L₂-edge to gain insight on the geometry around Mo atoms. This method is then applied to a series of molybdenum sulfide compounds to rationalize their structures.

A.P. Freitas, R. F. André, C. Poucin, T. K.-C. Le, J. Imbao, B. Lassalle-Kaiser, S. Carenco. Guidelines for the Molybdenum Oxidation State and Geometry from X-Ray Absorption Spectroscopy at the Mo L_2,3-Edges. J. Phys. Chem. C 2021, 10.1021/acs.jpcc.1c01875.

Transition metal carbides (TMCs) have attracted great interest due to their mechanical and catalytic properties but their syntheses generally require energy-consuming processes with temperatures above 800 °C. We report here a solid-state metathesis reaction between metal chlorides (ZrCl₄, NbCl₅, MoCl₃, MoCl₅, HfCl₄, TaCl₅, WCl₆) and potassium dispersed in carbon. Within seconds, it produces carbide or metallic nanoparticles of diameter below 50 nm supported on carbon. Based on thermodynamic and kinetic considerations, we propose a mechanism explaining the coexistence of several phases (metal, carbide, hydride) and their occurrence at each step of the reaction.

R. F. André, F. D'Accriscio, A. P. Freitas, G. Crochet, C. Bouillet, M. Bahri, O. Ersen, C. Sanchez, S. Carenco, Green Chem., 2021, 10.1039/D1GC01097B

Copper nanoparticle synthesis was studied by thorough characterization of the organic reactions happening during the synthesis. The reduction of copper(II) acetate by oleylamine resulted in a high amount of water and few by-products while the reduction of copper(II) acetylacetonate resulted in a low amount of water and many products. The nanoparticles showed different abilities to further dehydrogenate and transaminate oleylamine in the synthesis reaction pot. This was explained by the presence of a copper oxide phase in the nanoparticles prepared from copper acetate.

A. Pesesse, S. Carenco, Cat. Sci. Tech.., 2021, 10.1039/D1CY00639H.

Interlayer silylation of layered sodium octosilicate (Na-Oct) with various organoalkoxysilanes was conducted using hexadecyltrimethylammonium ion-exchanged layered octosilicate as an intermediate in the presence or absence of tetrabutylammonium fluoride (TBAF). The degree of silylation was increased by adding TBAF. It is suggested that fluoride ions perform a nucleophilic attack on the alkoxysilanes, which promotes the silylation reaction.Several functional groups were grafted with this procedure. Overall TBAF appears as a relevant catalyst for the covalent interlayer surface modification of layered silicates with organic functional groups.

M. Yatomi, M. Koike, N. Rey, Y. Murakami, S. Saito, H. Wada, A. Shimojima, D. Portehault, S. Carenco, C. Sanchez, C. Carcel, M. Wong Chi Man and K. Kuroda, Eur. J. Inorg. Chem., 2021, ejic.202100050.