sophiecarenco

"Domaine prioritaire dans la R&D des pays industrialisés, les nanotechnologies seront à l’horizon 2030 essentielles aux ingénieurs pour faire face aux crises environnementales, à la raréfaction de matières premières stratégiques et à la demande croissante d’énergie. Les chimistes y jouent un rôle de premier plan."

Cet article publié dans le dossier spécial sur la chimie de La Jaune et la Rouge discute du rôle des chimistes dans les nanotechnologies. Sommaire du dossier | Lire l'article.

S. Carenco, La Jaune et la Rouge 2019, 749, 46-47.

We implement an in situ electrochemical Transmission Electron Microscopy (in situ EC-TEM) methodology for studying electrocatalysts of the oxygen evolution reaction (OER) during operation, by using model cobalt oxide Co₃O₄ nanoparticles. Surface amorphization occurs, yielding a nanometric cobalt (oxyhydr)oxide-like phase during OER. This process is irreversible and occurs to an extent that has not been described before. Furthermore, pH and counterions of the electrolytes impact this restructuration, shedding light on the materials properties in neutral phosphate electrolytes.

N. Ortiz Peña, D. Ihiawakrim, M. Han, B. Lassalle-Kaiser, S. Carenco, C. Sanchez, C. Laberty-Robert, D. Portehault, O. Ersen, ACS Nano 2019, 13, 11372.

Copper and nickel are particularly interesting first-raw metals for their abundance and relevance in several branches of catalysis. In order to synthesize crystalline bimetallic phosphide Ni-Cu-P nanoparticles, core-shell copper‑nickel nanoparticles were reacted with white phosphorus (P₄). Surprisingly, hollow monocrystalline (Ni,Cu)₂P nanoparticles were formed alongside Cu nanoparticles and crystallized in a phase isostructural to Ni₂P.

A.-M. Nguyen, M. Bahri, S. Dreyfuss, S. Moldovan, A. Miche, C. Méthivier, O. Ersen, N. Mézailles, S. Carenco, Chem. Mater. 2019, 31, 6124-34.

(Gd,Ce)₂O₂S anisotropic nanoparticles with hexagonal structure exhibit colors varying from white to brown with increasing Ce concentration. Bandgap engineering is thus possible, from 4.7 eV to 2.1 eV. Surprisingly, due to the limited thickness of the lamellar nanoparticles, the bandgap of the nanoparticles is direct as validated by density functional theory on slabs. The fine control of the bandgap over a wide range, solely triggered by the cation ratio, is rarely described in the literature and highly promising for further development of this class of compounds.

C. Larquet, A.-M. Nguyen, E. Glais, L. Paulatto, C. Sassoye, M. Selmane, P. Lecante, C. Maheu, C. Geantet, L. Cardenas, C. Chanéac, A.Gauzzi, C. Sanchez, S. Carenco, Chem. Mater. 2019, 31, 5014-23.

N-Heterocyclic carbene-stabilized copper nanoparticles are synthesized using a NHC-borane and mesitylcopper(I) in thermal conditions (refluxing toluene for 2.5 h). Nanoparticles with a size distribution of 11.6 ± 1.8 nm were obtained. The interaction between Cu NPs and NHC ligands was probed by XPS, showing the covalent binding of the NHC to the surface of the nanoparticles.

Mechanistic studies suggest that the NHC-borane plays two roles: contributing to the reduction of [CuMes]₂ to release Cu⁰ species and providing NHC ligands to stabilize the copper nanoparticles.

X. Frogneux, L. Hippolyte, D. Mercier, D. Portehault, C. Chaneac, C. Sanchez, P. Marcus, F. Ribot, L. Fensterbank, S. Carenco, Chem. Eur. J. 2019, 25, 11481-85.

Understanding the surface reactivity of titanium oxides Magnéli phases that contain both Ti(IV) and Ti(III) is of prime importance. This article describes a new synthetic route to 50 nm carbon-free Ti₄O₇ and Ti₆O₁₁ nanoparticles.The surface reactivity of the Magnéli nanoparticles was quantitatively evaluated under different atmospheres with synchrotron radiation-based X-ray photoelectron spectroscopy, highlighting oxidized surfaces with lower conductivity than the core. This finding sheds a new light on the charge transfer occuring in these materials.

E. Baktash, J. Capitolis, L. Tinat, C. Larquet, T. H. C. Chan Chang, J.-J. Gallet, F. Bournel, C. Sanchez, S. Carenco, D. Portehault. Chem. Eur. J. 2019, 25, 11114-20.

New dumbbell‐shaped octasilsesquioxanes (T₈-POSS) are obtained by the condensation of organobridged silane precursors with partially condensed POSS. The synthesis based on corner-capping proceeds under mild reaction conditions (60 °C in toluene) upon a nucleophilic fluoride-catalyzed condensation. Two dumbbell-type T₈-POSS, one with a non-symmetrical urea-thiourea linker and the other one with a symmetrical malonamide linker, are described.

N. Rey, S. Carenco, C. Carcel, A. Ouali, D. Portehault, M. Wong Chi Man, C. Sanchez, Eur. J. Inorg. Chem. 2019, 27, 3148-56.

Formation of higher-value products from cheaper silicone precursors such as polymethylhydrosiloxane (PMHS) is a challenge for silicon chemistry. Here, we show that catalytic amount of potassium graphite can be used as an efficient radical initiator for the cleavage of Si–O bonds of hydrosiloxanes. Mechanistic investigations suggest that both the dismutation of the initial hydrosiloxane and the reduction of carbonyl derivatives by hydrosilylation are initiated with a radical pathway.

X. Frogneux, A. Pesesse, S. Delacroix, F. Ribot, S. Carenco, ChemCatChem 2019, 11, 3781-85.

Capping ligands play an important role in the chemistry of nanoparticles. Ultrathin monodisperse Ln₂O₂S_x oxysulfide nanoparticles (Ln = lanthanide) show promising luminescence and light absorption properties. Here, we show that the thermal stability of Gd₂O₂S_x nanocrystals is limited because of their non‐stoichiometric composition and strongly depends on the annealing atmosphere. Annealing the nanoparticles in air enables removing the ligands without altering the nanocrystals structure.

C. Larquet, D. Hourlier, A.-M. Nguyen, A. Torres-Pardo, A. Gauzzi, C. Sanchez, S. Carenco, ChemNanoMat 2019, 5, 539-46.

Gadolinium oxysulfide nanoparticles are suitable candidates for bimodal imaging Here, we synthesized and characterized bimetallic (Gd,Ce)₂O₂S nanoparticles and demonstrated that they are paramagnetic over a wide temperature range including the body one. The mixture of Gd and Ce magnetic centers enables a fine control of the magnetic properties up to high Ce concentrations (80%) and over a large range of magnetic moments, while photoemission properties are guaranteed up to 20% of Ce owing to a regular dispersion of the Ce centers.

C. Larquet, Y. Klein, D. Hrabovsky, A. Gauzzi, C. Sanchez, S. Carenco, EurJIc. 2019, 6, 762-765 | EurJIc Cover.

Les oxysulfures de métaux contiennent du soufre à un état d’oxydation négatif. Les oxysulfures de lanthanides cristallins sont utilisés depuis plus de cinquante ans mais les premières synthèses de nanoparticules datent du début du siècle. Cet article discute de la stratégie à adopter pour préparer de telles nanoparticules avec l’exemple de l’oxysulfure de gadolinium. Ces nanoparticules présentent une surface réactive, comme le montre la formation spontanée de sulfates à l’air libre.

C. Larquet, A.-M. Nguyen, T. K.-C. Le, M. Avila-Gutierrez, S. Carenco, L'Actualité Chimique. 2019, 436, 28-31.

Ce document est l’adaptation française du "Brief Guide" de l’IUPAC pour la nomenclature en chimie inorganique.

Il présente un aperçu des règles essentielles de la nomenclature pour générer noms et formules pour les composés inorganiques, notamment les composés de coordination et les composés organométalliques.

J. Capitolis, S. Delacroix, X. Frogneux, E. Medina, N. Rey, L. Tinat, S. Carenco, L'Actualité Chimique. 2019, 437, 12-18.