carbonyl group


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Related to carbonyl group: hydroxyl group, Alkoxy group

carbonyl group

carbonyl group (kärˈbənĭl), in chemistry, functional group that consists of an oxygen atom joined by a double bond to a carbon atom. The carbon atom is joined to the remainder of the molecule by two single bonds or one double bond. If the carbonyl group is joined only to alkyl groups or aryl groups, the compound is a ketone; if it is joined to at least one hydrogen atom, the compound is an aldehyde. The chemical reactivity of aldehydes and ketones is primarily due to the difference in electronegativity between carbon and oxygen. Because oxygen has the greater affinity for electrons, it acquires a partial negative charge, becoming electron-rich; the carbon atom of the carbonyl group thus becomes electron-deficient, acquiring a partial positive charge. One major type of reaction of aldehydes and ketones involves the addition of an electron-rich chemical species to the electron-deficient carbon atom of the carbonyl group. Another type of reaction is due to the tendency of the electron-deficient carbon atom of the carbonyl group to partially attract electrons from carbon atoms adjacent to it in the molecule, thus increasing the acidity of hydrogen atoms that are bonded to the adjacent carbon.
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carbonyl group

[′kär·bə‚nil ‚grüp]
(organic chemistry)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The spectra showed that Blends are being hydrolyzed, in this sense changes were observed in the carbonyl group region (C=O) between 1750-1650 [cm.sup.-1].
The hydrogen bonding analysis from FTIR demonstrated that the limited intersegmental hydrogen bonding can occur between carbonyl groups of the hard segments in the hard domain because most of the hard segments "dissolve" in the soft domains and scarcely hard segment can form hard domains.
[sup.13]C MAS NMR spectra confirmed the disappearance of carbonyl groups when the precursor was heated at 400[degrees]C; this is in agreement with the results of IR analyses.
According to Michell and Higgins (2002), the group around 1,730 [cm.sup.-1] is almost exclusively due to the carbonyl groups of acetoxy groups in xylan.
C3-H appeared down field to C6-H by the lactonized carbonyl group.
In the present work, the carbonyl group C=O (peak A) was found at 1585[cm.sup.-1] for 0 wt.
This suggests that the crosslinked structure originated from the reaction between the carbonyl group and the protein could strengthen cohesion of acrylic resin molecules and endow them with hydrophobicity to some degree, despite the fact that the protein crosslinking agents themselves were hydrophilic.
Nucleophilic elbowThe Ser163 which carries out the nucleophilic attack on the carbonyl group of TAG is a part of a more conserved structure called nucleophilic elbow.
Using the lowest energy geometries that are also capable of undergoing reaction (ones whose geometry had the carbonyl group close enough to the hydride source and was close enough to hydrogen bond to two of the catalytic residues), only 6 were incorrectly predicted compared to 13 if the enzyme is assumed to prefer an anti-Prelog docking geometry.
The synthesis of bis(carbamoylcarboxylic) acids was developed using two different core dianhydride substrates (Figure 2), such as 3,3',4,4'-benzophenonetetracarboxylic dianhydride (1) (formally two phthalic anhydrides linked by a carbonyl group) and 1,2,4,5-benzenetetracarboxylic dianhydride (2) (two anhydride groups with a benzene ring bridge).
Among many steroids tested, those possessing a carbonyl group at position 3, a methyl group at 7, a hydroxyl group at positions 1, 2, 4, 11, or 19, or a saturated B ring, with or without a 4-5 double bond, were inactive.