A Magnetically Separable Heterogeneous Deallylation Catalyst: [CpRu(η³‐C₃H₅)(2‐pyridinecarboxylato)]PF₆ Complex Supported on a Ferromagnetic Microsize Particle Fe₃O₄@SiO₂

Abstract

The highly reactive and chemoselective homogeneousdeallylation catalyst CpRu(η3‐C3H5)(4‐substituted‐2‐pyridinecarboxylato) was immobilized on microsize spherical Fe3O4@SiO2 particles. The resultant heterogeneous catalyst displays high saturation magnetization, weak coercive forces and high levels of dispersibility. The catalyst has increased the utility of deallylation by allowing the reaction to be conducted without extra additives. The only co‐product of the reaction is a volatile allyl ether compound. Here, we demonstrate the efficient deallylation and separation of highly polar multifunctional compounds as well as multiple rounds of catalyst recycling without significant loss of reactivity. The usefulness of this catalyst has been confirmed by the synthesis of a triribonucleotide 3–5 U. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Oxide Nanomaterials: Synthetic Developments, Mechanistic Studies, and Technological Innovations

“…[306] For applications involving inorganic catalysts, though, there are many points which speak for amorphous silica as the separation material, for example, its easy deposition from solution with controlled layer thicknesses, the electrically insulating properties and the presence of hydrophilic silanol groups on the materials surface as anchors for further functionalization. [310][311][312][313] Although silica-coated magnetic cores can also facilitate the removal of homogeneous catalysts, [314] we focus on their use in heterogeneous catalysis in the following.…”

Fe3O4 Nanoparticles-Supported Palladium-Bipyridine Complex: Effective Catalyst for Suzuki Coupling Reaction

“…Additionally, as MNPs have a high surface area, MNPs-supported catalysts also show high dispersion and reactivity with a high degree of chemical stability. The various types of organic reactions using the MNPs-supported catalysts that have emerged recently include C-C coupling reactions [17][18][19][20][21][22][23][24], hydroformylation [25,26], hydrogenation [27][28][29][30][31][32][33][34][35], C-N coupling reaction [36,37], oxidation [38][39][40][41][42][43], cleavage of allyl esters and ethers (deallylation catalyst) [44], enantioselective acylation [45], multicomponents Aza-Sakurai reaction [46], the Paal-Knorr reaction [47], CO 2 cycloaddition reactions [48], asymmetric hydrosilylation of ketones [49], and esterification [50]. Other reports of MNPs-supported catalysts include O-Alkylation reaction [51], halogen exchange reaction [52], polymerization reactions [53], enzymes for carboxylate resolution [54], amino acids for ester hydrolysis [55], organic amine catalysts promoting Knoevenagel [56], one-pot reaction cascades [57], and the various acidcatalyzed reactions (deprotection reaction of benzaldehyde ...…”

Oxidische Nanomaterialien: Von der Synthese über den Mechanismus zur technologischen Innovation

“…B. seine leichte Abscheidung aus der Lösung unter Kontrolle der erhaltenen Schichtdicke, seine elektrisch isolierenden Eigenschaften und die Anwesenheit hydrophiler Silanolgruppen auf der Oberfläche, die als Ankerpunkte für weitere Funktionalisierungsreaktionen genutzt werden können. [310][311][312][313] Siliciumdioxidbeschichtete magnetische Kerne erleichtern auch in großem Umfange die Abtrennung homogener Katalysatoren, [314] doch wenden wir uns im Folgenden gezielt ihrem Einsatz in der heterogenen Katalyse zu.…”