Portal de Periódicos da CAPES

Synthesis and Properties of 5,10,15,20-Tetrakis(3,5-di- t -butyl-2-nitrophenyl)porphyrin: Conformational Stabilities of the Respective Atropisomers and Oxygenation Capabilities of the Iron(III) and Manganese(III) Complexes

1987; Oxford University Press; Volume: 60; Issue: 5 Linguagem: Inglês

10.1246/bcsj.60.1649

1348-0634

Takeshi Miyamoto, Shigeru Takagi, Tai Hasegawa, Seizi Tsuzuki, Eitaro Takahashi, Kojiro Okude, Itsuki Banno, Yukiyoshi Sasaki,

Metal-Catalyzed Oxygenation Mechanisms

Abstract The synthesis and properties of new, bulky atropisomeric porphyrins are described. Four atropisomers of 5,10,15,20-tetrakis(3,5-di-t-butyl-2-nitrophenyl)porphyrins has been easily separated and purified by column chromatography. The isomers all have different thermal stabilities toward atropisomerization. Below 60 °C, however, they have rather high conformational stabilities, and an iron(III) or manganese(III) ion has been incorporated into each isomer, with a retention of the ligand conformation. By the use of these metal complexes, the catalytic oxygenation reactions, i.e., the epoxidation of olefins (styrene, α-methylstyrene, cyclohexene, and cyclooctene) and the hydroxylation of alkanes (cyclohexane and heptane), have been done in the presence of hypochlorite or iodosylbenzene as an oxidant. Products analyses by GLC show that these new complexes effectively catalyze the oxygenations in higher yields or in more selective ways, than the corresponding TPP complexes.