Bimetallic nickel-cobalt nanoparticles are highly sought for their potential as catalytic and magnetic nanoparticles. These are typically prepared in organic solvents in the presence of strong stabilizing ligands such as...

Molybdenum accepts oxidation states from -II to +VI. This versatility is highly beneficial for applications in catalysis, especially combined with sulfur to form the ubiquitous MoS 2 material. X-ray Absorption Near Edge Spectroscopy (XANES) is a particularly welladapted technique to study simultaneously both elements, since the K-edge of S (2472 eV) and the L 2,3 -edges of Mo (2520 -2625 eV) have similar absorption energies. It provides information on both the electronic and local structure 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 addition, only few recent studies focus on the measurement of the signal of Mo-based reference compounds, meaning that the references from the literature do not benefit from recent technical progress. Notwithstanding theoretical tools that allow a deep understanding of such spectroscopic data, the lack of reference spectra prevents a quick yet reliable interpretation. In this work, we provide a method for the interpretation of X-ray absorption near edge structure (XANES) data at the Mo L 2,3 -edges, based on a library of spectra of simple Mo compounds. From our analysis, we suggest using the L 3 -edge to determine the oxidation state (in selected cases) and the L 2 -edge to gain insight on geometry around the Mo atoms. This method is then applied to a series of molybdenum sulfides compounds in order to rationalize their structures. Besides this example, these guidelines should help to qualitatively interpret XANES of Mo at L 2,3 -edges in future studies.

Hydrosilylation reactions are commonly used for the reduction of carbonyl bonds in fine chemistry, catalyzed by transition metal complexes. The current challenge is to expand the scope of metal-free alternative catalysts, including in particular organocatalysts. This work describes the organocatalyzed hydrosilylation of benzaldehyde with a phosphine, introduced at 10 mol%, and phenylsilane at room temperature. The activation of phenylsilane was highly dependent on the physical properties of the solvent such as the polarity, and the highest conversions were obtained in acetonitrile and propylene carbonate with yields of 46 % and 97 %, respectively. The best results of the screening over 13 phosphines and phosphites were obtained with linear trialkylphoshines (PMe 3 , P n Bu 3 , POct 3 ), indicating the importance of their nucleophilicity, with yields of 88 %, 46 % and 56 %, respectively. With the help of heteronuclear 1 HÀ 29 Si NMR spectroscopy, the products of the hydrosilylation (PhSiH 3-n (OBn) n ) were identified, allowing a monitoring of the concentration in the different species, and thereby of their reactivity. The reaction displayed an induction period of ca. 60 min, followed by the sequential hydrosilylations presenting various reaction rates. In agreement with the formation of partial charges in the intermediate state, we propose a mechanism based on a hypervalent silicon center via the Lewis base activation of the silicon Lewis acid.