Porphyrins complexes with manganese

Tab. 2 Electrochemical data for manganese complexes with porphyrins, Schiff bases, and related macrocyclic ligands in nonaqueous media...

Kinetics and mechanisms of dissociation of manganese complexes with porphyrins in mixed protolytic solvents 04MI14. 

In the first topic - Fine Chemistry - the methodologies used in the het-erogenisation of manganese complexes into solid supports are briefly described. The major part of the section focuses on examples of heterogeneous manganese complexes with salen- and porphyrin-type ligands used as catalysts in the epoxidation of alkenes their catalytic activity is discussed as a... 

Spasojevic, I. and I. Batinic-Haberle (2001). Manganese(III) complexes with porphyrins and related compounds as catalytic scavengers of superoxide. Inorg. Chim. Acta. 317, 230-242. 

These reports sparked off an extensive study of metalloporphyrin-catalyzed asymmetric epoxidation, and various optically active porphyrin ligands have been synthesized. Although porphyrin ligands can make complexes with many metal ions, mainly iron, manganese, and ruthenium complexes have been examined as the epoxidation catalysts. These chiral metallopor-phyrins are classified into four groups, on the basis of the shape and the location of the chiral auxiliary. Class 1 are C2-symmetric metalloporphyrins bearing the chiral auxiliary at the... 

In company with manganese porphyrin complex, ruthenium porphyrins have already shown great catalytic activity in the intermolecular amidation of saturated G-H bonds. However, examples of amidation of aromatic... 

Manganese nitrosyl porphyrins [215] are considered good models for the iron-nitric oxide analogs, which are relatively unstable but very vital to many biological operations. A six-coordinate manganese nitrosyl porphyrin of the form (por)Mn(NO)(L), where por can be TTP (TTP = tetra(4-methylphenyl)porphine) and L = piperidine, methanol, 1-methyhmidazole, has been prepared [216] in moderate yields by the reductive nitrosylation of the (por)MnCl complex with NO in piperidine. The crystal structures of these compounds give indication of a linear Mn-NO bond [215]. 

The first mononuclear manganese(III) peroxo species without a porphyrin ligand, [Mn(3,5-Pr 2pzH)(HB(3,5-Pr 2pz)3)(02)] (144),was prepared from the reaction of [ Mn"(HB(3,5-Pr 2pz)3) 2](OH)2 with excess of H2O2 (10-20 equivalents) in the presence of 3,5-Pr 2pzH (2 equivalents) at room temperature. It is a six-coordinate complex with a side-on peroxo group. 

D KIE associated with alkane hydroxylation by cytochromes P-450 and intermolec-ular D KIE in the alkane hydroxylations catalysed by manganese and iron porphyrin complexes... 

Nitrosyl-aryl porphyrin complexes, with iron, 6, 107 Nitrosyl complexes with chromium, 5, 301 with manganese, 5, 773... 

Apart from the catalytic properties of the Mn-porphyrin and Mn-phthalo-cyanine complexes, there is a rich catalytic chemistry of Mn with other ligands. This chemistry is largely bioinspired, and it involves mononuclear as well as bi- or oligonuclear complexes. For instance, in Photosystem II, a nonheme coordinated multinuclear Mn redox center oxidizes water the active center of catalase is a dinuclear manganese complex (75, 76). Models for these biological redox centers include ligands such as 2,2 -bipyridine (BPY), triaza- and tetraazacycloalkanes, and Schiff bases. Many Mn complexes are capable of heterolytically activating peroxides, with oxidations such as Mn(II) -> Mn(IV) or Mn(III) -> Mn(V). This chemistry opens some perspectives for alkene epoxidation. 

Irradiation of manganese azides derived from Mn(III) porphyrin, cyclam, and polyamide complexes represents one of the earliest methods reported for the preparation of nitrido manganese complexes (Eq. (40)) [50], Additional methods have become available for the synthesis of manganese nitrides that utilize ammonia in combination with oxidants such as Cl2, PhIO, NaCIO, and NBS (Eq. (41)) [51-53]. Employing these methods, the manganese nitrides incorporating porphyrin, phath-locyanine, cyclam, salen, and bidentate Schiff base complexes have been documen-... 

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