Manganese complexes carbonylation

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. 

Photolysis of cationic alkoxycarbene iron complexes [193] or alkoxycarbene manganese complexes [194] has been used to replace carbonyl groups by other ligands. The alkylidene ligand can also be transferred from one complex to another by photolysis [195], Transfer of alkylidene ligands occurs particularly easily from diaminocarbene complexes, and has become a powerful synthetic method for the preparation of imidazoline-2-ylidene complexes [155,196]. 

Manganese (continued) carbonyl halides, 3 78, 79-80 complexes with phosphine, etc., 6 10 carbonyls... 

Analogously, reaction of group 7 metal carbonyl anions M(CO)5 (M = Mn, Re) with MeC(CFFI), gave cyclopropylcarbinyl complexes. Flowever, whereas rhenium produces the normal (/-metal bonded cyclopropylcarbinyl complex, the manganese complex furnished (cyclopropylacetyl)Mn(CO)5, where carbonyl insertion into the manganese-alkyl bond occurred (equation 56)114. 

Neither the palladium nor nickel catalyst described will promote the carbonylation of saturated aliphatic halides as noted above. However, this reaction can be catalyzed with cobalt (17) or iron (77) and probably with manganese (18) carbonyl anion salts. These carbonyl anions are strongly nucleophilic species and readily displace halide or other good leaving groups from primary or secondary positions giving alkyl metal carbonyl complexes. 

Manganese complexes of 2[(l-hydroxy-2-naphthalenyl)carbonyl]benzoic acid (12) are reported to be effective photostabilizers for polymers,47 and manganese phthalocyanine shows smoke-retarding properties in polystyrene.31... 

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. 

A manganese(O) carbonyl complex, Mn2(CO)io, is found to be a fairly active catalyst for the reaction of 1-hexene with HSiEt3 or HSi(OEt)3 in toluene or THF at 40 °C55. Kinetic study suggests that HMn(CO)s is the catalytically active species. 

An unusual reaction, with loss of a phenyl group from HSnPh3, occurs with some din-uclear manganese-hydride carbonyl complexes (equation 84)240. The chemistry outlined in the previous equations, involving elimination of H2, occurs in many regions of the periodic table and produces good yields of the metal-tin bonded complex. 

The rhenium compound 10 is rather unreactive. Carbonylation (100°C, 200 atm) gives Cp Re(CO)3, while treatment with I2 affords Cp Re(CO)2-(I)2. It does not react with ethyne, diazomethane, or phosphines under conditions where other dimetal complexes with multiple MM bonds do so (78). The manganese complex 8, also somewhat unreactive, reacts with phosphites by Mn=Mn cleavage. In the case of P(OEt)3 the two products Cp Mn(CO)2[P(OEt)3] and CpMn(CO)[P(OEt)3]2 form in a 1 1 ratio (51). 

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