Cobalt (II) Schiff base catalyzed aerobic oxidation of secondary alcohols to ketones

Halloysite clay nanotubes with Fe–Al deposits for the oxidation of benzyl alcohol

Fe–Al/HNT catalysts are prepared and their application in the oxidation of benzyl alcohol to benzaldehyde at a temperature of 80 °C is investigated.

Ruthenium carbonyl complexes supported by pyridine-alkoxide ligands: synthesis, structure and catalytic oxidation of secondary alcohols

Five novel trinuclear ruthenium carbonyl complexes were synthesized and their application in oxidation of secondary alcohols was also researched.

NH3⋅H2O: The Simplest Nitrogen-Containing Ligand for Selective Aerobic Alcohol Oxidation to Aldehydes or Nitriles in Neat Water

Aqueous ammonia (NH3⋅H2O) has been shown to serve as the simplest nitrogen-containing ligand to effectively promote copper-catalyzed selective alcohol oxidation under air in water. A series of alcohols with varying electronic and steric properties were selectively oxidized to aldehydes with up to 95 % yield. Notably, by increasing the amount of aqueous ammonia in neat water, the exclusive formation of aryl nitriles was also accomplished with good-to-excellent yields. Additionally, the catalytic system exhibits a high level of functional group tolerance with -OH, -NO2, esters, and heteroaryl groups all being amenable to the reaction conditions. This one-pot and green oxidation protocol provides an important synthetic route for the selective preparation of either aldehydes or nitriles from commercially available alcohols.

A cobalt Schiff base complex on TiO2nanoparticles as an effective synergistic nanocatalyst for aerobic C–H oxidation

A cobalt Schiff base complex on TiO₂nanoparticles possess excellent photocatalytic properties under visible light for the aerobic benzylic C–H oxidation.

Highly selective aerobic oxidation of alkyl arenes and alcohols: cobalt supported on natural hydroxyapatite nanocrystals

Cobalt was successfully immobilized on natural hydroxyapatite nanocrystals which was obtained from cow bones (Co–NHAp). NHAp as the support enhanced both catalytic activity and selectivity in aerobic oxidation of alkyl arenes and alcohols.

Aerobic benzylic C–H oxidation catalyzed by a titania-based organic–inorganic nanohybrid

The visible light photocatalytic properties of TiO₂/AA/Co organic–inorganic nanohybrid in the aerobic benzylic C–H oxidation was exploited.

Starch-coated maghemite nanoparticles functionalized by a novel cobalt Schiff base complex catalyzes selective aerobic benzylic C–H oxidation

The CoL₂@SMNP nanocatalyst catalyzed heterogeneous aerobic oxidation of benzylic C–H bonds of saturated hydrocarbons and alcohols to the related carbonyl compounds.

Aerobic oxidation of alcohols with bifunctional transition-metal catalysts bearing C-N chelate ligands

The aerobic oxidation of alcohols with a family of bifunctional Ir, Rh, and Ru complexes bearing C-N chelating ligands derived from primary benzylic amines was investigated. The isolable amido-Ir complexes [Cp*Ir{kappa(2)(N,C)-(NHCR(2)-2-C(6)H(4))}] (R=C(6)H(5), CH(3); Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) effected the oxidation of secondary alcohols smoothly under atmospheric pressure of air at 30 degrees C in THF to give the corresponding ketones in good yields. The hydrido(amine)-Ir complexes [Cp*IrH{kappa(2)(N,C)-(NH(2)CR(2)-2-C(6)H(4))}] and the combined catalyst system involving the chloro(amine)-Ir complex [Cp*IrCl{kappa(2)(N,C)-(NH(2)CR(2)-2-C(6)H(4))}] and KOC(CH(3))(3) were also found to be effective catalysts, whereas the tertiary amine complex [Cp*IrCl{kappa(2)(N,C)-(N(CH(3))(2)CH(2)-2-C(6)H(4))}], which does not have a metal/NH moiety, did not show catalytic activity. The employment of primary alcohols in the aerobic reaction with the Cp*IrCl complex and KOC(CH(3))(3) resulted in the formation of esters through oxidative dimerization.

Immobilization of cobalt(II) Schiff base complexes on polystyrene resin and a study of their catalytic activity for the aerobic oxidation of alcohols

The copper-catalyzed [3+2] azide-alkyne cycloaddition and the Staudinger ligation are readily applicable and highly efficient for the immobilization of cobalt Schiff base complexes onto polystyrene resins. Stepwise synthesis of polymer-bound Schiff bases followed by their subsequent complexation with metal ions were successfully carried out. Direct covalent attachment of preformed homogeneous cobalt Schiff base complexes to the resins was also possible. The catalytic efficiency of the so-prepared polystyrene-bound cobalt Schiff bases was studied for the oxidation of alcohols to carbonyl compounds using molecular oxygen as oxidant. The immobilized complexes were highly efficient and even more reactive than the corresponding homogenous analogues, thus affording better yields of oxidized products within shorter reaction times. The supported catalysts could easily be recovered from the reaction mixture by simple filtration and reused for subsequent experiments with consistent catalytic activity.

Highly efficient selective oxidation of alcohols to carbonyl compounds catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride in the presence of molecular oxygen

Efficient selective oxidation of alcohols to carbonyl compounds by molecular oxygen with isobutyraldehyde as oxygen acceptor in the presence of metalloporphyrins has been reported. Ruthenium (III) meso-tetraphenylporphyrin chloride (Ru(TPP)Cl) showed excellent activity and selectivity for oxidation of various alcohols under mild conditions. Moreover, different factors influencing alcohols oxidation, for example, catalyst, solvent, temperature, and oxidant, have been investigated. In large-scale oxidation of benzyl alcohol, the isolated yield of benzaldehyde of 89% was observed.