Herein is highlighted an original disproportionation mechanism for the formation of hexagonal closed packed cobalt nanoparticles starting from low-valent cobalt complexes. By coupling experimental and theoretical studies, we demonstrate that oleylamine promotes the disproportionation of the starting metal complexes and controls the growth of the nanocrystals, in contrast to the role of reducing reagents proposed elsewhere. We also decipher the sensitivity of the synthesis in regard to the nature of the phosphine and of the halogen ligands in the starting cobalt precursors. Understanding of the mechanism allows the development of a less expensive and less toxic synthesis of these nanoparticles by decreasing the amount of oleylamine in alkane solvents. Finally, an extension of this process is presented and allows reaching size-and shape-controlled nanosphere and nanorod nickel nanoparticles.
Understanding of cobalt nanorods’ (Co NRs) formation still remains challenging when it comes to enhancing their anistropic properties applicable in magnetic or catalytic areas. Herein, we propose a mechanism for...
The low temperature regioselective hydrosilylation of various alkenes with (1,1,1,3,5,5,5-heptamethyltrisiloxane) MDHM is described using Mn2(CO)10 under UV irradiation with Mn loadings as low as 1 mol%, in the absence of additives and with excellent selectivity and yields.
Unlike the classical organometallic approach, we report here a synthetic pathway requiring no reducing sources or heating to produce homogenous hexagonal close packed cobalt nanocrystals (NCs). Involving a disproportionation process, this simple and fast (6 min) synthesis is performed at room temperature in presence of eco-friendly fatty alcohols to passivate Co NCs. Through a recycling step, the yield of Co NCs is improved and the waste generation is limited making this synthetic route cleaner. After an easy exchange of the capping ligands, we applied them as unsupported catalyst in the stereo-selective semi-hydrogenation of alkynes.
ASSOCIATED CONTENT
Supporting InformationExperimental procedures, microscopic analyses (TEM, SEM-EDX), size histograms, characterization of products resulting from alkynes catalysis and magnetic measurement information. The Supporting Information is available free of charge on the ACS Publications website.
Herein, we describe the unexpected ring opening of the epoxide group of allyl glycidyl ether and 4-vinylcyclohexene oxide in polymethylhydrosiloxane (PMHS) hydrosilylation reaction using 0.1 mol% of Co2(CO)8 as catalyst....
This work describes the study of behavior of the d-substituted and d-non-substituted exo-cyclic double bond of c-alkylidenebutenolides with dialkylcuprates. The addition reaction was found to be regioselective to afford the 1,6-conjugate adduct up to 87% yield.
The catalytic hydrosilylation of alkenes is a major industrial reaction and a very efficient and atom-economical way to obtain functional organosilane compounds and cross-linked materials. Platinum-based catalysts are currently preferred...
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