4277-32-1Relevant articles and documents
Catalytic oxygen atom transfer promoted by tethered Mo(VI) dioxido complexes onto silica-coated magnetic nanoparticles
Colaiezzi, Roberta,Crucianelli, Marcello,Di Giuseppe, Andrea,Ferella, Francesco,Lazzarini, Andrea,Paolucci, Valentina
, (2021/11/30)
The preparation of three novel active and stable magnetic nanocatalysts for the selective liquid-phase oxidation of several olefins, has been reported. The heterogeneous systems are based on the coordination of cis-MoO2 moiety onto three different SCMNP@Si-(L1-L3) magnetically active supports, functionalized with silylated acylpyrazolonate ligands L1, L2 and L3. Nanocatalysts thoroughly characterized by ATR-IR spectroscopy, TGA and ICP-MS analyses, showed excellent catalytic performances in the oxidation of conjugated or unconjugated olefins either in organic or in aqueous solvents. The good magnetic properties of these catalytic systems allow their easy recyclability, from the reaction mixture, and reuse over five runs without significant decrease in the activity, either in organic or water solvent, demonstrating their versatility and robustness.
A stand-alone cobalt bis(dicarbollide) photoredox catalyst epoxidates alkenes in water at extremely low catalyst load
Guerrero, Isabel,Romero, Isabel,Teixidor, Francesc,Vi?as, Clara
supporting information, p. 10123 - 10131 (2021/12/27)
The cobalt bis(dicarbollide) complex, Na[3,3′-Co(η5-1,2-C2B9H11) (Na[1]), is an effective photoredox catalyst for the oxidation of alkenes to epoxides in water. Advantageous features of Na[1] include its lack of photoluminescence, high solubility and surfactant behavior in aqueous media, as well as the donor ability of the carborane ligand and high oxidizing power of the Co4+/3+ couple. These features differentiate it from the well-known and widely used photosensitizer tris (2,2′-bipyridine) ruthenium(ii) ([Ru(bpy)3]2+), which also participates in electron transfer through an outer sphere mechanism. A comparison of the catalytic performance of [Ru(bpy)3]2+ with Na[1] for alkene photo-oxidation is fully in favor of Na[1], as the former shows very low or null efficiency. With a catalyst loading of 0.1 mol% conversions between 65-97% have been obtained in short reaction times, 15 minutes, with moderate selectivity for the corresponding epoxide, due to the formation of side products as diols. But when the catalyst loading is reduced to 0.01 mol%, the selectivity for the corresponding epoxide increased considerably, being the only compound formed after 15 minutes of reaction (selectivity >99%). High TON values have been obtained (TON = 8500) for the epoxidation of aromatic and aliphatic alkenes in water. We have verified that Na[3,3′-Co(η5-1,2-C2B9H11)2] acts as a photocatalyst in both the epoxidation of alkenes and in their hydroxylation in aqueous medium with a higher rate for epoxidation than for hydroxylation. Preliminary photooxidation tests using methyl oleate as the substrate led to the selective epoxidation of the double bond. These results represent a promising starting point for the development of practical methods for the processing of unsaturated fatty acids, such as the valorisation of animal fat waste using this sustainable photoredox catalyst. This journal is
Rare earth Ce- and Nd-doped spinel nickel ferrites as effective heterogeneous catalysts in the (ep)oxidation of alkenes
Adam, Mohamed Shaker S.,Hafez, Aly M.,Khalaf, Mai M.
, p. 3237 - 3250 (2020/07/09)
Cerium (Ce)- and neodymium (Nd)-doped spinel nickel ferrites catalysts system were synthesized using a cost-effective sol–gel route. The as-prepared nickel ferrites and its doped Ce and Nd nanomaterials were characterized in terms of Fourier transform infrared spectrophotometry, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, selected area diffraction pattern, zeta potential and magnetism techniques. Their catalytic potential was examined in the (ep)oxidation of 1,2-cyclooctene by using hydrogen peroxide (H2O2) or tert-butylhydroperoxide (t-BuOOH). Optimization of various parameters, including solvent, oxidant and catalyst type revealed that chloroform (CHCl3) or 1,2-dichloroethane as a solvent and t-BuOOH as an oxidant were found to be the best choice for this catalytic system. The catalytic efficiency was found as Nd–NiFe2O4 > Ce–NiFe2O4 > NiFe2O4. Further, the applied nanocatalysts could be easily renovated and exhibited high catalytic reactivity for 5 times of recycling experiments with long-time durability. A reasonable discussion of the mechanism reaction reinforced the action of these spinel catalysts.
