Properties of Metal Carbonyls

Metal carbonyls are extremely toxic, particularly those which have high vapor pressure at room temperature. Some of them are even more toxic than carbon monoxide itself. Because of high volatility, tetracarbonylnickel and pentacarbonyliron are exceptionally harmful. 

Most metal carbonyls easily undergo oxidation reactions while exposed to air, and some of them even inflame in air. Therefore, reactions involving metal carbonyls should be carried out in the atmosphere of inert gas under a well-ventilated hood. Owing to their covalent bonds, metal carbonyls are volatile and generally well soluble in nonpolar organic solvents (Table 2.16). 

The values of bond energies are not in agreement with the observed direction of reactivity of these carbonyls. The energy of the breaking of the first M —CO bond determines the reactivity of carbonyls if a dissociative mechanism occurs. This energy is con- 

The reactions of carbonyl complexes may be divided into the following five groups  

Reactions involving the breaking of metal-metal bonds in polynuclear carbonyls. 

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For the equilibration processes to take place on the nmr time scale, the energetic barrier for interconversion of CO bonding modes cannot be great (usually <22 kcal/mol). While the fluxional properties of metal carbonyls will not be of concern to us here, they illustrate the facility for interconverting CO bonding modes, and suggest that if CO activation can be achieved beginning with a particular mode of coordination, carbonyls bound in other ways to metal atoms may also be activatable. ... 

Synthesis and Properties of Metal Carbonyl Clusters Containing Nitrido Ligands... 

General Photochemical Properties of Metal Carbonyls 2.1. SPECTROSCOPY... 

Broad agreement appears to have existed for some time as to the principles governing the formation, structure, and properties of metal carbonyl derivatives. Since there appears to be no need to repeat in detail what is well summarized in earlier reviews 1, 2, 10), the next section of this article attempts only to limn broadly the rules and correspondences which are widely cited in papers in the area. Emphasis will be placed upon the generalizations which provide the strands weaving together the chemistry of many compounds into a manageable fabric. Subsequent sections summarize the compounds involved, element by element. In the interests of brevity, clarity, and quick comprehension, in most cases formulas and common abbreviations are used, rather than systematic names. 

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