Carbonyl is an organic functional group (C=O) composed of carbon and oxygen atoms connected by double bonds, and it is a component of functional groups such as aldehydes, ketones, carboxylic acids and carboxylic acid derivatives. In organic reactions, carbonyl groups can undergo nucleophilic addition reaction, reduction reaction and so on. The carbonyl group of aldehyde or ketone can also undergo oxidation reaction. In addition, in coordination chemistry, carbon monoxide ligands are also called carbonyl groups.
There are many kinds of compounds containing carbonyl groups, which cannot be listed in detail in the entry. For details of properties and preparation methods, please refer to the entries of corresponding types of compounds (such as aldehydes, ketones, carboxylic acids, carboxylic esters, anhydrides, acyl peroxides, amides, acyl halides, ketenes, isocyanates, etc. ).
material structure
The bond length of the double bond of carbonyl group C=O is about 1.22 angstrom. Because the electronegativity of oxygen (3.5) is greater than that of carbon (2.5), the electron cloud distribution of C=O bond is biased towards oxygen atom, which determines the polarity and active chemical reactivity of carbonyl group.
Bonding modes in clusters: In carbonyl cluster chemistry, carbonyl ligands have many different bonding modes. The most common carbonyl ligands are terminal ligands, but carbonyl groups often connect two or three metal atoms to form μ2 or μ3 bridged ligands.
Sometimes carbon atoms and oxygen atoms in carbonyl groups will participate in bonding. For example, μ3-η is a bridging ligand with a Harpto number of 2, which connects three metal atoms. The feedback π bond formed by the central atom of metal strengthens the M-C bond and activates the -C-O bond.