Polymeric graphitic carbon nitride (g-C 3 N 4 ) is a layered graphite-like nitrogen-rich material, bearing the potential ability to reductively adsorb molecular oxygen for catalytic allylic oxidation. Furthermore, N-hydroxyphthalimide (NHPI) has been recognized as an efficient catalyst for aerobic oxidation of various organic compounds under mild conditions in the presence of various co-catalysts. We present here a promising strategy for employing such nitride-rich g-C 3 N 4 combined with NHPI to form an allorganic metal-free composite and have examined its activity for allylic oxidation with molecular oxygen as the primary terminal oxidant. In the case of allylic oxidation aisophorone catalyzed by g-C 3 N 4 /NHPI gave priority to its corresponding carbonyl compound and epoxide. The effects of various reaction conditions on the catalytic reaction were optimized, affording 74.8 % conversion with 44.4 % selectivity of ketoisophorone at 130°C in 5 h. Repeated runs demonstrated that the catalyst was stable for at least three cycles without noticeable loss of its catalytic activity.

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Four novel pyridine Schiff bases derived from 2,6-pyridinedicarbaldehyde and substituted o-hydroxylaromatic amines and their manganese(II) complexes were synthesized and characterized by elemental analyses, ESI-MS analysis, thermal analysis (TGA), H-NMR, IR and UV-vis. The activity of these complexes as catalysts in cyclohexene autoxidation were investigated and the effects of various reaction conditions on the catalytic reaction were optimized to obtain as high as 99.6% conversion with 95.0% selectivity of epoxycyclohexane at 40 uC for 6 h using molecular oxygen as an oxidant in acetonitrile. The result presents excellent catalysts for epoxidation of cyclohexene under mild temperature and atmospheric oxygen (O 2 ) pressure.

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