Asymmetric porphyrine-containing complexe

The oxidation of saturated hydrocarbons in the presence of iron- or manganese-containing catalysts can be achieved by using a variety of oxidants including alkyl hydroperoxides, peroxycarboxylic acids, iodosyl-benzene, dihydrogen peroxide, and dioxygen (9-11). It has been shown that chiral iron- and manganese-porphyrin complexes catalyze the asymmetric epoxidation of unfunctionalized alkenes (75). Except for a number of experiments in which up to 96 % enantiomeric excess (ee) has been reported (16,17), in most epoxidation reactions with chiral porphyrins only a low to moderate enantiomeric excess of the product is obtained (18,19). In association with these catalysts, alkyl hydroperoxides and iodosylbenzene are often used as primary oxidants (18,19). 

Vibrational methods applied to proteins and model complexes include IR, resonance Raman, and NRVS [173, 178-180]. The interpretation of these vibrational data combined with DPT studies on the reaction mechanisms of heme proteins is frequently based on the porphine approximation, i.e. aU porphyrin ring substituents are neglected. Whereas this is intuitively a good approximation for D4h-symmetric macrocycles (e.g., TPP complexes), it is noteworthy that the biologically observed hemes all contain asymmetric substitution patterns on the porphyrin ring [181]. 

Porphyrins that contain Ru-Mo and Os-Mo dinuclear complexes was reported by Collman et al One of the isolated complexes, [RuMo(OEP)(TPP)][PF6] 30 (OEP = octaethylporphyrin, TPP = tetraphenylporphyrin), possesses a unique deformational isomerism. The Ru-Mo metal-metal bonds of the two molecules in the asymmetric unit are of different lengths. 

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