Manganese pentacarbonyl hydride

We recognized that the isoelectronic hydrides H2Fe(CO)4 and HCo(CO)4 behaved as pseudo-nickel tetracarbonyls (hydride displacement principle). Moreover, manganese pentacarbonyl hydride (VII, 11), on which we later worked in Munich, was similar in many physical properties to iron pentacarbonyl, leading us to postulate a Drawing-in of the hydrogen... 

B, SODIUM SALT OF MANGANESE PENTACARBONYL HYDRIDE AND MANGANESE PENTACARBONYL HYDRIDE... 

Manganese pentacarbonyl hydride is a liquid, colorless when pure, but usually yellow from traces of manganese carbonyl due to decomposition. Its extrapolated boiling point is about 100°. Since it is quite air-sensitive and volatile, it is most conveniently handled in a vacuum system. With diazomethane it gives CH3Mn(CO)6 and with tetrafluoroethylene it gives HCF2CF2Mn(CO)8. ... 

The fact that quinones may form tt complexes with transition metals was first recognized by Sternberg et al. 53), who found that butyne reacts with iron pentacarbonyl in sunlight to afford duroquinone-iron tricarbonyl (XIX). These authors also reported that manganese pentacarbonyl hydride yields durohydroquinone under similar conditions whereas nickel carbonyl did not react 53a). However, more recent work has established that duro-quinone and some other substituted quinones are capable of forming Ni(0) complexes, most of which are surprisingly stable. 

The reaction between manganese pentacarbonyl hydride and hexa-fluorobut-2-yne is stereospecihc, yielding principally, if not only, trans-CF3CH C(CF3)Mn(CO)s (97). 

In the addition of transition metal hydrides to unsaturated fluorocarbons reaction proceeds best with tetrafluoroethylene. So far most of the studies have been carried out with manganese pentacarbonyl hydride. By addition of this hydride to the double bonds of either chlorotrifluoroethylene or... 

There appear to be limitations on the extent to which reactions between transition metal hydrides and fluoroolefins can be used to make o-bonded fluorocarbon-metal compounds. Unsuccessful attempts have been made to add manganese pentacarbonyl hydride to 1,1-difluoroethylene, 1-chloro-... 

Reaction between trifluoromethyl iodide and manganese pentacarbonyl hydride occurs readily even below room temperature to afford manganese pentacarbonyl iodide and trifluoromethane (124). Perfluoromethylmanganese pentacarbonyl is not produced. Similarly, although perfluoroalkyl iodides and sodium pentacarbonylmanganate(—1) react, perfluoroalkylmanganese pentacarbonyls are not obtained (95, 100). 

Recently, polynuclear tetracarbonyls of the two heavier metals in the manganese sub-group have been discovered. The first was for technetium (2) as a major by-product during attempts to prepare the pentacarbonyl hydride, and more recently, for rhenium (3) by an analogous route. The dimetal deca-carbonyl is treated first with sodium amalgam in tetrahydrofuran solution. After a time, the solvent is evaporated and cyclohexane and phosphoric acid are added and the heterogeneous mixture is refluxed desired product is found in the cyclohexane layer. It was later discovered that the use of sodium boro-hydride in the first step instead of sodium amalgam led to the same products. 

Recently proof has been reported for a heterometallic bimolecular formation of aldehyde from a manganese hydride and acylrhodium species [2], Phosphine free, rhodium carbonyl species show the same kinetics as the cobalt system, i.e. the hydrogenolysis of the acyl-metal bond is rate-determining. Addition of hydridomanganese pentacarbonyl led to an increase of the rate of the hydroformylation reaction. The second termination reaction that takes place according to the kinetics under the reaction conditions (10-60 bar, 25 °C) is reaction (3). The direct reaction with H2 takes place as well, but it is slower on a molar basis than the manganese hydride reaction. 

The chemistry of the metal carbonyl hydrides and metal carbonylates remained the principal research topic for Hieber until the 1960s. He mentioned in his account [25], that it was a particular pleasure for him that in his laboratory the first hydrido carbonyl complexes of the manganese group, HMn(CO)5 and HRe(CO)5, were prepared by careful addition of concentrated phosphoric acid to solid samples of the sodium salts of the [M(CO)5] anions, giving the highly volatile hydrido derivatives in nearly quantitative yield [45, 46]. In contrast to HCo(CO)4 and its rhodium and iridium analogues, the pentacarbonyl hydrido compounds of manganese and rhenium are thermally remarkably stable, and in... 

Manganese.—Elimination of transition-metal hydride from metal alkyls and addition of metal hydrides to alkenes are usually considered to be cA-processes. Since acylmanganese compounds undergo stereospecific reversible decarbonylation, thermal decomposition of (eryrAro-2,3-dimethylpentanoyl)(pentacarbonyl)manga-nese(i) should allow the determination of the stereochemistry of elimination of [MnH(CO)8] (Scheme 4). However, both the erythro and a mixture of the erythro and threo acyl complexes decompose thermally to give the same mixture of cis- and trans-3-methylpent-2-ene and 3-methylpent-l-ene under conditions which do not isomerize these alkenes. It is suggested that the mechanism involves interconversion of... 

Substances that catch fire spontaneously in air without an ignition source are called pyrophoric. These include several elements— white phosphorus, the alkali metals (group lA), and powdered forms of magnesium, calcium, cobalt, manganese, iron, zirconium, and aluminum. Also included are some organometallic compounds, such as ethyllithium (LiC2H5) and phenyllithium (LiQHj), and some metal carbonyl compounds such as iron pentacarbonyl, Fe(CO)5. Another major class of pyrophoric compounds consists of metal and metalloid hydrides, including lithium hydride, LiH ... 

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