Manganese tris

Manganese tris(acetylacetonate) exists in two crystalline forms, ft and y. High quality structures of both have been published.99,100 Each exhibits definite evidence of Jahn-Teller distortion. In the jS-form the average Mn—O distances are 1.95 and 2.00 A in a compressed M06 octahedron the... 

Apart from the lanthanide and actinide trifluorides all of the transition-metal trifluoride structures known show the metal atom to be six-co-ordinated in fluorine. Indeed in only one other case, that of manganese tri-fluoride, is there an appreciable distortion from octahedral symmetry. The distortions may be correlated with the electronic configurations of the metal atoms. Table 4 shows that, in the first transition series tri-... 

Manganese, tri carbonyl methylcyclopentadienyl. See Tricarbonyl (methylcyclopentadienyl) manganese Manganese trioxide. See. Manganese oxide (ic) Manganese violet... 

Table 3 Manganese Tris(Imido) Complexes Theory Versus Experiments" ...

A wide variety of additives is available to refiners to improve gasoline quality, including octane number. Although lead has been banned in most western Countries, other octane-enhancers like MMT (Methyl-Cyclopentadienyl Manganese Tri-carbonyl) are widely used. Gibbs, (1989), presents a review of the various types of additives currently employed. Oxidation inhibitors and metal deactivators are normally added in the refinery or processing plant to prevent oxidation and gum formation. Dyes for product identification and antiknock compounds can be added prior... 

Ligand substitution reactions of n-cyclopentadienyl manganese tri-carbonyl ... 

Tri-n-octylphosphine oxide [78-50-2] M 386.7, m 59.5-60°, pK jt <0. Mason, McCarty and Peppard [J Inorg Nuclear Chem 24 967 7962] stirred an O.IM solution in benzene with an equal volume of 6M HCl at 40° in a sealed flask for 48h, then washed the benzene solution successively with water (twice), 5% aq Na2C03 (three times) and water (six times). The benzene and water were then evaporated under reduced pressure at room temperature. Zingaro and White [J Inorg Nucl Chem 12 315 7960] treated a pet ether solution with aqueous KMn04 (to oxidise any phosphinous acids to phosphinic acids), then with sodium oxalate, H2SO4 and HCl (to remove any manganese compounds). The pet ether solution was slurried with activated alumina (to remove phosphinic acids) and recrystd from pet ether or cyclohexane at -20°. It can also be crystd from EtOH. 

For example, if we consider the list of what Brock (1992) calls Mendeleev s Tater predictions , then alongside the five successes—eka-manganese (technetium, discovered in 1939), tri-manganese (rhenium, 1925), dvi-tellurium (polonium, 1898), dvi-caesium (francium, 1939), eka-tantalum (protactinium, 1917)—there were four failures— coronium (which turned out to be ionised iron), ether, eka-niobium and eka-caesium. (Since many of these predictions were made in the 1871 paper, Brock s reason for calling them the later predictions was presumably that they were the ones whose empirical fate was settled only later.)... 

Barbeau, C., Dichmann, K. S. Ricard, L. (1973) Structure cristalline et moleculaire du cyclopentadienyle dicarbonyle tri-phenylphosphine manganese, MnCsHsfCO P gHsta, Can. J. Chem 51,3027-3031. 

Sometimes, a direct ion-pairing of the chiral cations and anions 8 or 15 is necessary to maximize the NMR separation of the signals [115,116]. Cationic species as different as quaternary ammonium, phosphonium, [4]heterohelice-nium, thiiranium ions, (rj -arene)manganese, ruthenium tris(diimine) have been analyzed with success (Fig. 23). 

Nevertheless, manganese nodules can, at best, be considered to be similar to land-based nickel laterites, and consequently most of the processing techniques that have been tried are similar to those used on lateritic ores. Reduction roasting followed by ammonia leaching, as in the Nicaro process, and high-temperature sulfuric acid leaching, as in the Moa Bay operation, have been extensively tried to process nodules. 

Heterocyclic nitrogen donors and their adducts with zinc chloride have been studied.623,624 A large number of other ligand systems have also been characterized, for example, zinc halide adducts of 2,2-dimethylpropane-1,3-diamine and hexamethylphosphoramide have been studied.625,626 The formation of mixed ligand complexes with chloride and substituted pyridines has been studied.627 The zinc tris(pyridyl) chloride anion has also been structurally characterized.628 Manganese(II) ions have been used to probe the stereochemistry in reactions of zinc halides with pyrazine.629... 

A similar ring expansion has been reported in the oxidation of cyclopropanol 225 with manganese(III) tris(2-pyridinecarboxylate) to generate the / -keto radical, which is allowed to add to the silyl enol ether 226 [124], The... 

In the CV of [MnIV(LMe2)]+, this reversible Mn(I V)/Mn(III) one-electron transfer is observed at Em = -0.26 V vs Fc+/Fc. All other tris(phenolato)manganese complexes display this process at a similar redox potential. At more negative potentials, the Mn(III)/Mn(II) couple gives rise to a reversible one-electron reduction wave atEm —0.87 V, Eq. (10). 

Alternatively, pyranosyl radicals can be generated through the reduction of 3,4,6-tri-O-benzyl glucal epoxide with Cp2TiCl2 and manganese metal.136 With the conformationally restricted 1-phenylseleno-D-xylose derivatives 151 and 152 (4Ci conformation) their reaction with Bu3SnCH2 CH=CH2 in the presence of AIBN (Scheme 51) affords the corresponding a-C-pyranosyl derivatives (153) preferentially.137... 

Nitroarenes are reduced to anilines (>85%) under the influence of metal carbonyl complexes. In a two-phase system, the complex hydridoiron complex [HFe,(CO)u]2-is produced from tri-iron dodecacarbonyl at the interface between the organic phase and the basic aqueous phase [7], The generation of the active hydridoiron complex is catalysed by a range of quaternary ammonium salts and an analogous hydrido-manganese complex is obtained from dimanganese decacarbonyl under similar conditions [8], Virtually no reduction occurs in the absence of the quaternary ammonium salt, and the reduction is also suppressed by the presence of carbon monoxide [9], In contrast, dicobalt octacarbonyl reacts with quaternary ammonium fluorides to form complexes which do not reduce nitroarenes. 

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