Manganese complexes, obtained from

Following our early studies (89, 90), we have recently investigated derivatives of manganese carbonyl obtained from reactions between Mn(CO)5X (X usually Br) and organic sulfur ligands (93). Manganese carbonyl chelate complexes are formed in which sulfur is covalently bonded to manganese, or forms a coordinate bond as an electron donor. 

Telluroacetone coordinated to manganese was obtained from a tellurium-bridged dinuclear manganese complex and dimethyldiazomethane4. 

Thallium occurs in crooksite, lorandite, and hutchinsonite. It is also present in pyrites and is recovered from the roasting of this ore in connection with the production of sulfuric acid. It is also obtained from the smelting of lead and zinc ores. Extraction is somewhat complex and depends on the source of the thallium. Manganese nodules, found on the ocean floor, contain thallium. 

The reaction of Mn(CO)jBr and methyl isocyanide was also carried out (Table V) the products are analogous to those obtained from phenyl isocyanide and the manganese complex. 

The spectrum of the low-spin manganese(n) complex, [Mn(dppe)2(CO)(CN-Bu)]2+, (dppe = Ph2PCH2CH2PPh2), in a CH2C12/THF glass is shown in Figure 4.4(a).24 The spin Hamiltonian parameters, obtained from least-squares... 

Simple transition metal halides react cleanly with alkali metal boratabenzenes. In this way sandwich-type complexes 32 of V (27), Cr (64), Fe (58), Ru (61), and Os (61) have been made. The corresponding nickel complexes seem to be nonexistent, quite in contrast to NiCp2 in attempted preparations, mixtures of diamagnetic C—C linked dimers were obtained (29). In the manganese case, high sensitivity to air and water has precluded preparative success until now. Some organometallic halides have added further variations to the main theme. The complexes 33 of Rh and 34 of Pt were obtained from [(COD)RhCl]2 and [Me3PtI]4, respectively (61). 

In a similar manner, Jt-allyl complexes of manganese, iron, and molybdenum carbonyls have been obtained from the corresponding metal carbonyl halides [5], In the case of the reaction of dicarbonyl(r 5-cyclopentadienyl)molybdenum bromide with allyl bromide, the c-allyl derivative is obtained in 75% yield in dichloromethane, but the Jt-allyl complex is the sole product (95%), when the reaction is conducted in a watenbenzene two-phase system. Similar solvent effects are observed in the corresponding reaction of the iron compound. As with the cobalt tetracarbonyl anion, it is... 

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. 

Grigg and co-workers (383) found that chiral cobalt and manganese complexes are capable of inducing enantioselectivity in 1,3-dipolar cycloadditions of azomethine ylides derived from arylidene imines of glycine (Scheme 12.91). This work was published in 1991 and is the first example of a metal-catalyzed asymmetric 1,3-dipolar cycloaddition. The reaction of the azomethine yhde 284a with methyl acrylate 285 required a stoichiometric amount of cobalt and 2 equiv of the chiral ephedrine ligand. Up to 96% ee was obtained for the 1,3-dipolar cycloaddition product 286a. 

Similar results have been obtained from porphyrin complexes of other metals.315 Few attempts appear to have been made to catalyze 02 production from these higher oxidation state manganese derivatives and this would appear to be an area warranting further study. 

Nature of the Metallic Salt. The data in Figures 15, 16, and 17 also show the influence of another parameter—the nature of the metallic salt. The two kinds of salts were chosen because the chlorides are salts of a strong acid, and the acetate is that of a weak acid. The data obtained from both the duration of the reaction and the diamine quantity show that the kind of salt used is important to mechanochemical com-plexation. Use of manganese acetate gives scission of a larger number of complexing centers than does use of choride salts. 

Vinylidene complexes have been obtained from reactions between PhC=CEPh3 (E = Si, Ge, or Sn) and manganese complexes (11, 18) solvolysis of the C-E bond is followed by transfer of a proton from the solvent. The yields (E = Si, 0% Ge, 1% Sn, 15%) are inversely proportional to the stability of the intermediate tp-alkyne complex. 

Binuclear manganese complexes (55) have been obtained from their mononuclear analogs, either by heating in an inert atmosphere, or by treating them with Mn(OEt2)(CO)2(i C5H5) (74) ... 

There are no routes yet to homoleptic metal isocyanide anions. If one considers the interesting products obtained from methyl iodide additions to molybdenum (43) and manganese (44) carbonyl isonitrile anions, negatively charged isocyanide complexes should have some interesting chemistry. Also, now that a simple route to [CpFe(CNR)2]2 complexes has been devised (45), the synthesis of the anion [CpFe(CNR)2] could provide a route to a range of products including heterometal-metal bonded systems. 

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