Manganese carbonyl hydride

Table 1. Formylated Cyclopropanes 7 and Cyclopropanes 8 by Cobalt and Manganese Carbonyl Hydride Mediated Hydroformylation/Hydrogenation of Cyclopropenes ...

The manganese hexacarbonyl cation is stable in a dry atmosphere, but moisture causes hydrolysis to the hydride and subsequently to manganese carbonyl. 

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... 

The oxidative addition of silicon hydride to cyclopentadienyl manganese carbonyl also provide a convenient route to chiral complexes (213,250) (eq. [78]). 

The reaction of metal carbonyl dimers with silicon hydrides also probably involves an initial oxidative addition step. Chiral silyl-cobalt and silyl-manganese carbonyl complexes have been obtained through the reaction of optically active organosilicon hydrides with metal carbonyls65 68 (equation 15 and 16). Phosphine-substituted cobalt complexes were similarly obtained by reaction of a chiral hydrosilane with Co2(CO)6L2 [L = PPh3, P(OPh)3, P(c-C6Hn)3]69. 

Evidence for rc(-l) in complex compounds appears in the synthesis of the carbonyl anion 1Tc(CO)5], the carbonyl hydride [HTc(CO)s]°, and the heteronuclcar carbonyl anion TcFe2(CO)i2] . Their existence was suggested by a comparison of their TR absorption bands with those of the corresponding compounds of manganese and rhenium, however, no structural determinations or magnetic measurements were reported. 

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 manganese carbonyl may be converted to pentacarbonylhydridomanganese by hydrogen in the presence of CO, by magnesium in the mixture of H2SO4, water, and methanol, or by LiAlH4. [MnH(CO)5] is a colorless, weakly acidic compound, well soluble in water pA =7.1) and in organic solvents. In air this hydride rapidly decomposes to [Mn2(CO)io] and H2. 

Re2(CO)io] is more stable than analogous compounds of technetium and manganese. [M2(CO)iq] carbonyls, where M = Re or Tc, undergo reduction reactions with sodium amalgam or dispersed alkali metals to give [M(CO)5] , which upon treatment with nonoxidizing acids form carbonyl hydrides, [HM(CO)5] ... 

In addition to the yellow-orange trimer mentioned above, a large amount of a red derivative was also isolated, whose spectrum is shown in the lower part of the figure. Analysis, molecular weight and magnetic and chemical properties of this derivative will be reported. This second compound may be related to the red carbonyl hydride of manganese reported by HIEBER, BECK and ZEITIER (4). obtained by similar chemical transformations on the... 

A metal hydride intermediate was suggested. The authors note that [Mn(CO)6] reacts with water to yield the hydride [HMn(CO)s] and carbon dioxide [208]. In a very recent communication [208a], it has been reported that both rhenium and manganese carbonyls having the formula [LM(CO)s] are attacked by nucleophiles to give insertion products, and that facile isotopic exchange occurs between H2 0 and the 0 of coordinated CO groups. 

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. 

It is also of interest to compare the acid dissociation constants for the carbonyl hydrides of vanadium, manganese, and cobalt. The heptacovalent HV(C0)6, which ionizes to form the hexacovalent anion [V(CO)J (11), and the pentacovalent HCo(CO)4, which ionizes to form the tetracovalent anion [Co(CO)4] (98), are both strong acids, whereas the hexacovalent HMn(CO)s, which ionizes to form the pentacovalent anion [Mn(CO)5] is a weak acid (K = 0.8 X 10 ) (5). These equilibria thus favor the hexacoordinate derivative when possible. 

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