| Co-Investigator(Kenkyū-buntansha) |
SUENOBU Tomoyoshi Osaka University, Graduate School of Engineering, Assistant Professor, 大学院・工学研究科, 助手 (90271030)
OGO Seiji Osaka University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (60290904)
|
|---|
| Research Abstract |
Manganese(V)-oxo species are generated by the stepwise electron transfer oxidation of manganese porphyrins with two equivalents of tris(2,2'-bipyridine)ruthenium(III) (Ru(bpy)_3^<3+>) via formation of manganese(IV)-oxo species. Addition of Ru(bpy)_3^<3+> to an MeCN solution of olefins (styrene, cyclohexene) containing water in the presence of a catalytic amount of a series of several manganese porphyrins.affords epoxides, diols and aldehydes efficiently. Epoxides are converted to the corresponding diols by hydrolysis, and are further oxidized to the corresponding aldehydes which are four-electron oxidized products of olefins. Ethylbenzene is also oxidized to 1-methylbenzylalchol using (TMP)Mn^III(OH), (Cl_8TPP)Mn^III(OH) and (F_<20>TPP)Mn^III(OH), whereas adamantane is oxidized to 1-adamantanol only by using (Cl_8TPP)Mn(OH). The oxygen source in the substrate oxygenation was confirmed to be water using ^18O labeled water. The presence of H_2O is essential to accelerate the catalytic oxygenation of substrates with Ru(bpy)_3^<2+>. A manganese dendrimer promotes not only the catalytic two-electron oxidation of olefins but also four-electron oxidation to the corresponding aldehydes as compared with the monomer manganese porphyrin. The photocatalytic oxygenation of substrates with water has been made possible using cobalt(III) amine complexes, Ru(bpy)_3^<2+>, and water-soluble manganese porphyrins. The four-electron oxidation of water to oxygen has also been examined using multi-nuclear manganese porphyrins.
|
