Word Finder - carbonyl

definition

In organic chemistry, a divalent functional group, (-CO-), characteristic of aldehydes, ketones, carboxylic acids, amides, carboxylic acid anhydrides, carbonyl halides, esters and others.

definition

Any compound of a metal with carbon monoxide, such as nickel carbonyl, Ni(CO)4.

The carbonyl group is not ketonic in character since it yields neither an oxime nor hydrazone.

The resulting compound, nickel carbonyl, which was described to the Chemical Society in 1890, is both formed and decomposed within a very moderate range of temperature, and on this fact he based a successful process for the extraction of nickel from its ores.

By transformations of the carbonyl group, and at the same time of the hydroxyl group, many interesting types of nitrogen compounds may be correlated.

A larger and more important series of condensations may be grouped together as resulting from the elimination of the elements of water between carbonyl (CO) and methylene (CH 2) groups.

Thus a double bond of oxygen, as in the carbonyl group CO, requires a larger volume than a single bond, as in the hydroxyl group - OH, being about 12.2 in the first case and 7.8 in the second.

Thus oxygen varies according as whether it is linked to hydrogen (hydroxylic oxygen), to two atoms of carbon (ether oxygen), or to one carbon atom (carbonyl oxygen); similarly, carbon varies according as whether it is singly, doubly, or trebly bound to carbon atoms.

The principal chromophores are the azo, -N = N -, azoxy, = N 2 O, nitro, - N02, nitroso, - NO, and carbonyl, = CO, groups.

The carbonyl group by itself does not produce colour, but when two adjacent groups occur in the molecule, as for example in the a-diketones (such as di-acetyl and benzil), a yellow colour is produced.

Nascent hydrogen reduces them to primary alcohols, and phosphorus pentachloride replaces the carbonyl oxygen by chlorine.

Chromic acid converts it into phosgene (carbonyl chloride, COC1 2).

On oxidation, the molecule is split at the carbonyl group and a mixture of acids is obtained.

Sodium amalgam reduces them to secondary alcohols; phosphorus pentachloride replaces the carbonyl oxygen by chlorine, forming the ketone chlorides.

This was burnt mouth-down in the oven., and the ashes on the ground reduced the red haematite to black magnetic oxide of iron; some traces of carbonyl in the ash helped to rearrange the magnetite as a brilliant mirror-like surface of intense black.

It reacts with carbonyl compounds, giving semi-carbazones, and in consequence is frequently used for characterizing such substances.

Nickel carbonyl, however, is extremely poisonous.

When mesitylene is used, the reaction does not proceed beyond the aldehyde stage since hydrocarbon formation is prevented by the presence of a methyl group in the ortho-position to the -CHO group. Acids and alkalis are in general without action on nickel carbonyl.

The vapour of nickel carbonyl burns with a luminous flame, a cold surface depressed in the flame being covered with a black deposit of nickel.

Pyrocatechin readily condenses to form heterocyclic compounds; cyclic esters are formed by phosphorus trichloride and oxychloride, carbonyl chloride, sulphuryl chloride, &c.; whilst ortho-phenylenediamine, o-aminophenol, and o-aminothiophenol give phenazine, phenoxazine and thiodiphenylamine.

It is also decomposed by carbonyl chloride (Besson, loc. cit.).

Of great interest are the carbonyl compounds.

The aldol condensation (using aldehydes, ketones, two different carbonyl partners, and the intramolecular variant ).

Deprotonation of the cysteine sulfhydryl by an adjacent histidine residue is followed by nucleophilic attack of the cysteine S on the peptide carbonyl carbonyl carbon.

Note how, within the plane of the sheet, backbone carbonyl oxygen atoms point toward backbone amino N atoms of the adjacent strand.

Application of the 18 electron rule to metal carbonyl complexes.

To establish the viability of 18 as a ligand we reacted it with a range of transition metal carbonyl compounds with mixed results.

Simultaneously, the other aspartate donates a proton to the oxygen of the peptide carbonyl group.

In contrast, formation of threohydrobupropion involves carbonyl reduction but does not involve cytochrome P450 isoenzymes.

What does the latter evidence indicate as regards the behavior of the carbonyl ligands at the temperature of the measurement?

The camphor molecule has one polar atom (a carbonyl oxygen) and three methyl groups.

In contact with chlorine monoxide it forms carbonyl chloride and thionyl chloride (P. Schiitzenberger, Ber., 1869, 2, p. 219).

It unites directly with chlorine, forming carbonyl chloride or phosgene (see below), and with nickel and iron to form nickel and iron carbonyls (see Nickel and IxoN).

The iron and ruthenium clusters not only lost their carbonyl ligands, but their cluster cores were also fragmented.