131336-20-4Relevant articles and documents
BIOMIMETIC MODELS OF CYTOCHROME P-450. SYNTHESIS AND CATALYTIC ACTIVITY OF Mn-PORPHYRINS BEARING COVALENTLY ATTACHED AXIAL LIGANDS
Banfi, Stefano,Montanari, Fernando,Quici, Silvio
, p. 435 - 441 (2007/10/02)
A description is presented of the synthesis of Mn(III)-tetraarylporphyrins 4 and 5 in which a pyridine axial ligand is connected, through a flexible chain of linearly disposed 9 and 14 atoms, to the tetra(2,6-dichlorophenyl)porphyrin, 6, structure, which is particulary resistant to oxidative degradation.In 4a and 4b the chain is bonded to the porphyrin skeleton through an amido bond in the meta position of a meso-phenyl ring.These Mn(III)-porphyrins proved to be catalytically even more efficient than 6 in the HOCl alkene epoxidations carried out under CH2Cl2-H2O two-phase conditions, at pH 10.5 and in the absence of a phase-transfer catalyst.The chemical stability and catalytic activity of 4a and 4b are lowered in alkene epoxidations promoted by 30percent-H2O2 in the presence of benzoic acid.Mn(III)-porphyrins 5a and 5b, in which one out of eight chorine atoms of 6 has been replaced by the amido group bearing the flexible chain, were less stable with respect to 4a and 4b in epoxidations promoted by either HOCl or 30percent-H2O2.Coordiantion of anchored pyridine and factors ruling catalytic efficiency and chemical stability of catalysts 4 and 5 are also examined.
