Carbon Monoxide and Metal Carbonyls

Complexes that contain carbon monoxide, CO, coordinated to a metal are known as carbonyls and are relevant to the many known carbonylation reactions. In addition to the mono-nuclear carbonyls, M(CO)x, a vast number of di- and poly-nuclear carbonyls containing metal-metal bonds are also known (e.g. Fc2(CO)9, Ru3(CO)i2). 

A sensitive tool to detect and measure the binding of CO to a metal is IR spectroscopy. CO normally shows a very strong band at 2143 cm when coordinated to a metal the CO bond strength, and hence the stretching frequency, v(CO), decreases due to population of the CO 7i -orbitals. Thus for example in the isostructural series, V(CO)g (1859 cm ), V(CO)g (1973 cm ) Cr(CO)g (2000 cm ) and Mn(CO)g (2095 cm ) there is a steady increase in v(CO) going from V to Mn as the metal centre becomes less electron rich and less able to back-donate to the CO. 

CO can bridge two or more li-block metals and some cases are known when the metal carbonyl oxygen also binds to strongly electropositive metals. 

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Use only chemical protective clothing that has undergone material and construction performance testing against carbon monoxide and metal carbonyls. If the concentration of vapor exceeds the level necessary to produce effects through dermal exposure, then responders should wear a Level A protective ensemble. 

Caution. Carbon monoxide and metal carbonyl complexes are highly toxic and must be handled at all times with care in an efficient hood. 

Organomagnesium compounds are less reactive than organolithium compounds [E] towards carbon monoxide and metal carbonyls. The initial reaction with carbon monoxide is similar — addition to give an acylmagnesium compound ... 

Caution. Carbon monoxide and metal carbonyls are highly toxic, and the reaction should be performed in an efficient fume hood. 

Several reviews have appeared on the role of carbon monoxide and metal carbonyl complexes in the commercial production of fuels and chemicals, with emphasis on Fischer-Tropsch-type hydrogenation processes. " ... 

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