Manganese-macrocycle complex

Pseudooctahedral complexes of the N4 donor cyclam of type [Mn(cyclam)X2]Y, where X and Y are a range of monovalent anions, have been reported." The efficacy of a complex of this type (with X = Y = Cl) as an oxidation catalyst has been probed. In another study both manganese(II) and manganese(III) complexes of the tetraaza macrocycle (175) have been characterized and were shown to be of types [MnLCy O.SHCl and [MnL(N3)2]N3. The traw -octahedral structures of both species have been confirmed by X-ray diffraction studies. 

The characterization, redox properties, and pulse radiolysis study of manganese(III) complexes of type [MnLCy (where L = cyclam, meso-, and rac-5,7,7,12,14,14-hexamethylcyclam (tet a and tet b, respectively)) have been reported." An X-ray crystal structure of the meso-5,l,l, 2, A, A-hexamethyl-l,4,8,ll-tetraazacyclotetradecane complex shows that the coordination geometry of the tet a complex is close to octahedral with the macrocycle coordinated equatorially and the chlorides occupying irons axial sites. 

The synthesis of the manganese(III) complex of the hexaaza macrocyclic ligand (176), derived from 2,3-butanedione and diethylenetriamine, and its use as a catalyst for the epoxidation of olefins using iodosylbenzene as oxidant has been reported." ... 

Manganese(III) complexes of a number of phenolate pendant arm macrocycles related to the above have also been reported. Thus, both l,4,7-tris(2-hydroxybenzyl)-l,4,7-triazacyclononane and l,4,7-tris(3-t-butyl-2-hydroxybenzyl)-l,4,7-triazacyclononane, on tris-deprotonation, afford monomeric pseudooctahedral complexes with this ion." ... 

The synthesis as well as spectral and electrochemical properties of a series of unsymmetrical bis(phenoxo)-bridged macrocyclic binuclear manganese(III) complexes based on (178), incorporating dissimilar coordination sites, have been reported." The bis(phenoxo)-bridged complexes yielded two reduction waves in the region 0.00V to —1.60V assigned to the process Mn2 —> Mn Mn Mn2 ]. In the positive region (0.00 V to +1.00 V), two oxidation couples were... 

There have been a number of other reports of the use of largely unsaturated, N4 donor macrocycles to generate 1 1 manganese(II) complexes." The majority of these have been assigned octahedral geometries in which two monodentate ligands occupy the remaining positions in the coordination sphere. 

Macrocyclic complexes of type [M11LX2] (where L = (190) and X = C1, Br, I, and NCS) have been synthesized." These complexes appeared exceptionally stable relative to other manganese(II) phosphine complexes. They can be manipulated in air for minutes without decomposition, a finding that was ascribed to the steric protection afforded by this macrocyclic ligand species. 

The stability constant (7=0.1, 25 °C) has been reported for the 1 1 manganese(II) complex of the related amide-containing, 15-membered macrocycle l,4,7-trimethylcarboxy-9,14-dioxo-1,4,7,10,13-pentaazacyclopentadecane as 14.7 (log value). ... 

Other high-spin, mononuclear manganese(II) complexes of mixed oxygen nitrogen macrocycles have been reported. ... 

The synthesis of a manganese(I) complex of the macrocyclic phosphine ligand l,5,9-triethyl-l,5,9-triphosphacyclododecane (L) has been reported. Thus, reaction of L with Mn(CO)5Br yields MnL(CO)2Br whose six-coordinate structure was confirmed by X-ray diffraction. 

The related manganese(I) complexes of type /uc-[MnL(CO)3] (where L is one of the tetrathia macrocycles 1,4,7,10-tetrathiacyclododecane, 1,4,8-11-tetrathiacyclotetradecane, or 1,4,7,10,13-pentathiacyclopentadecane) were obtained by reaction of /hc-[Mn(CO)3(CH3COO)3] with L in acetonitrile. These species are readily decarbonylated with Me3NO to yield the corresponding ci5-[Mn(CO)2(L)]+ species. The facial arrangements in the products containing the 12- and 15-membered ring macrocycles were confirmed by X-ray structure determinations. 

Riley DP, Weiss RH. Manganese macrocyclic ligand complexes as mimics of superoxide dismutase. J Am Chem Soc 1994 116 387-8. 

In addition there has been a recent review of manganese porphyrin chemistry (19) as well as of the aqueous and chloro complexes of the porphyrin species (20). These discussions are complemented by a discussion of the electrochemistry of manganese porphyrin compounds (21). Related studies include the phthalocyanine complexes (22), the manganese (III)-hemoglobin structure (23), and the characterization of macrocyclic complexes of manganese (24, 25). Other relevant chemistry involves the Schiff-base complexes of Mn(III) (26, 27, 28). 

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