24254-56-6Relevant articles and documents
Photooxygenation of alkanes by dioxygen with: P -benzoquinone derivatives with high quantum yields
Ohkubo, Kei,Hirose, Kensaku,Fukuzumi, Shunichi
, p. 731 - 734 (2016/07/06)
Alkanes were oxygenated by dioxygen with p-benzoquinone derivatives such as p-xyloquinone in alkanes which are used as solvents to yield the corresponding alkyl hydroperoxides, alcohols and ketones under visible light irradiation with high quantum yields (Φ = 1000, 1600%). The photooxygenation is started by hydrogen atom abstraction from alkanes by the triplet excited states of p-benzoquinone derivatives as revealed by laser-induced transient absorption spectral measurements.
Oxidation of cyclohexane by transition-metal complexes with biomimetic ligands
Silva, Ana Rosa,Mour?o, Teresa,Rocha, Jo?o
, p. 81 - 86 (2013/08/24)
This work reports the catalytic activity, in homogeneous phase, of transition-metal complexes of the first-row (V(IV), Mn(III), Fe(III) Co(III) and Cu(II)) with biomimetic Schiff base ligands with N2O2 coordination sphere, as well as an N4 (Fe(II)), in the room-temperature oxidation of cyclohexane using environmentally benign reagents: hydrogen peroxide (30 wt%) as the oxygen source and acetonitrile as the solvent. Nitric acid is also used as promoter of the oxidation reaction. The structure of the ligands is confirmed by FTIR, 1H NMR and high-resolution ESI mass spectrometry. The corresponding transition metal complexes are characterized by elemental analysis, high resolution ESI mass spectrometry, FTIR and UV-vis. Cyclohexanone and cyclohexanol are the main products of the oxidation of cyclohexane, obtained when the following complexes are used as homogeneous catalysts in only 1 mol% based on the substrate: VO(IV), Fe(III) and Cu(II) complexes with the N2O2 Schiff base, new Fe(II) complex with the Schiff base with N4 coordination sphere and commercial [VO(acac)2] with O4 coordination sphere. The Fe(III) complex with N2O2 Schiff base ligand ([Fe(salhd)Cl]) is the homogeneous catalyst with highest activity, which could be further enhanced by the addition of methyl electron donating groups to the N2O2 Schiff base aldehyde fragment (reaching 46% oxygenate yields and 45 turnover numbers). Cyclooctane and n-hexane could also be oxidized to the corresponding ketones and alcohols with higher turnover numbers than cyclohexane by the Fe(III) complex with N2O2 Schiff base ligand.