Porphyrin, superstructured iron

D. Lexa and J. M. Saveant, Supramolecular Effects in the Redox and Coordination Chemistry of Superstructured Iron Porphyrins, in Redox Chemistry and Interfacial Behaviour of Biological Molecules , eds.G. DryhurstandK. Niki, Plenum, New York, 1988, p. 1. 

The above-mentioned studies of superstructured iron(II) porphyrins are of great significance because they have demonstrated steric and environmental effects on the O2-binding and CO-binding reactions. Of particular relevance in... 

SUPRAMOLECULAR EFFECTS IN THE REDOX AND COORDINATION CHEMISTRY OF SUPERSTRUCTURED IRON PORPHYRINS... 

Diederich et al. had postulated that the highly reactive iron-oxo species, arising from oxygen transfer from the oxidant to the Fem site [87], should be greatly stabilised by enclosure within a dendritic superstructure. The catalytic potential of the dendrimers 6 a-c was determined in the epoxidation of alkenes [83 a, 88] (1-octene and cyclooctene) and the oxidation of sulphides [83 a] ((methylsulphanyl)benzene and diphenyl sulphide) to sulphoxides - in dichloro-methane with iodosylbenzene as oxidising agent. Compared to the known metal-porphyrin catalysts, 6a-c exhibit only low TON (7 and 28, respectively, for... 

Carbon monoxide reacts with [Fe(TPP)] to form a five-coordinate complex [Fe(TPP)CO], which can be reduced electrochemically to the corresponding iron(I) species from which, however,245 CO spontaneously dissociates. The Fe—CO interaction is stabilized by the,presence of hydrocarbon chains bound by amide linkages to the ortho position of the TPP phenyl rings. Carbon monoxide adducts of iron(I) complexes of a number of these superstructured porphyrins have been reported.245 The chemistry of these highly reduced species is of relevance to understanding240 the reactions of cytochrome P-450 and the peroxidases. 

The modulation of the reactivity by the basket-handle superstructures was mostly investigated for reactions involving a one-unit increase of the negative charge of the porphyrin complex Fe(II)(Fe(I)-, Fe(I) (Fe("0")2-redox reactions, complexation of iron(II) by anionic ligands. However, we will see that significant supramolecular effects also exist for the complexation of iron(II) by neutral nitrogen bases. 

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