Manganese carbonyl structure

Prolonged treatment of manganese carbonyl with azulenes gives unstable complexes of the type [Mn2(CO)6(azulene)2], the structures of which are uncertain (29). 

Only one complex in which a phospholyl ring acts as a (4 + 3) electron donor through its diene and its phosphorus atom taken separately, is structurally characterized. It has been prepared from a (l-phenylphosphole)-Mn2(CO)7 complex, in which the diene and the phosphorus atom are already complexed, (see Sect, n.4.) by cleavage of the phosphorus-phenyl bond with manganese carbonyl under UV at low temperature ... 

Another unusual species is the compound of Mn" and the imidazoyl anion [Mn3(imid-H)5 2imid], made from manganese carbonyl. The colourless crystals are air sensitive, and have a polymeric structure with alternating [MnN ] octrahedra and [MnN4] tetrahedra, bridged by the imidazole ligands. Each octahedral Mn is surrounded by four tetrahedral Mn s and each tetrahedron is surrounded by two other tetrahedra and two octahedra. 

Figure 7.3 Synthesis and electronic structure of bis(imino)pyridine manganese carbonyl complexes over three oxidation states.

The a-heteroaryl carbonyl structure has stimulated interest in organic synthesis because it is a highly prevalent motif in pharmaceuticals and natural products. In the year 2014, a manganese-catalyzed intermolecular C-H/C-H coupling of carbonyls and heteroarenes was developed (14CC4105).The presence of NaI04 is necessary for the catalytic reaction. These new reaction conditions allow gram-scale synthesis of a-heteroaryl carboxylic acids. 

The PMR spectra of the o - and tt -allyl complexes correspond very well with the spectra of the corresponding manganese and cobalt carbonyl complexes (9). Although the exact location of the tt -allyl group with respect to the metal is not known, the reaction with cyanide ion indicates that the TT -allyl group may be considered to be bidentate, a conclusion in full accord with the displacement of carbon monoxide in the conversion of a -to-tt-allyl cobalt and manganese carbonyls (9), and with the coordination of dimethyl-sulfoxide in the conversion of 7r-to-o -allyl palladium chloride (10). Structure(I) is tentatively proposed for the tt -allyl cyanocobaltate complex. 

A novel polyfunctional initiator has been prepared by the reaction of a copolymer of styrene and methyl methacrylate with polytetrafluoroethylene (PTFE) radicals generated photochemically from the monomer and manganese carbonyl. These radicals react with aromatic rings by addition and substitution so that the product copolymer from this reaction carries short PTFE chains with Mn(CO)6 end groups of, for example, structures (12). At 100 °C, scission of the CFj— Mn(CO)s bonds occurs with formation of active radicals, and the copolymer behaves as a polyfunctional macroinitiator. On heating this material with styrene or JV-vinyl-2-pyrrolidone a network structure and a graft copolymer respectively are formed. 

A number of complexes have been prepared from the electron-rich ligand 3,5-di(tert-butyl)-l,2,4-triphospholyl these include manganese carbonyl complexes and the manganocene, which has been structurally characterised. A paper explaining the facile silane dissociation in transition metal T -silane complexes Cp(CO)2M[p -H(SiH3 Cl )] (M = Mn, Tc and Re n = 1-3) (see, for example, 28) makes interesting reading. ... 

Reaction of the manganese and rhenium carbonyls, M2(CO)10, with Ru3(CO)12 or Os3(CO)12 in a 3 1 ratio yields the products [M(CO)5]2M (CO)4, with M = Re or Mn, M = Ru or Os. These are considered to be linear trinuclear metal systems. The only other trinuclear carbonyl derivative isolated is OsCo2(CO)n, obtained as one of a number of compounds from the reaction of Co2(CO)8 with H2Os(CO)4. No structural data are available for this compound (241). 

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