Substitution in Carbonyls - Carbon Monoxide Replacement

For the Group VI carbonyls replacement of 2,3 or 4 carbon monoxides by olefin ligands has been achieved. However, the substitution of four carbon monoxide ligands has only been formd with chelating ligands metal-tricarbonyl systems are usually markedly resistant to substitution. In the... 

While the replacement of carbon monoxide by a tertiary phosphine ligand represents one of the most fundamental substitution reactions in metal carbonyl chemistry, it was not until 1975, some 16 years after the... 

Very rarely can all the carbonyl groups in metal carbonyls be replaced by olefin Ugmids. Substitution of 2,3 or 4 carbonyl groups in Mo(CO) by unsaturated hydrocarbons has been observed, although four carbon monoxides are replaced only by certain dienes under fordng conditions ... 

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