Equilibrium vs ground-state planarity of the CONH linkage

Jean Demaison, A. Császár, Isabelle Kleiner, Harald Møllendal

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Planarity of the XC(=)NHY linkage has been investigated in unprecedented detail in a number of relatively simple compounds, including formamide (X = Y = H), acetamide (X = CH3, Y = H), urea (X = NH2, Y = H), carbamic acid (X = OH, Y = H), and methyl carbamate (X = OCH3, Y = H). Reliable estimates of the equilibrium structures of formamide, cyanamide, acetamide, urea, carbamic acid, methylamine, dimethyl ether, and methyl carbamate are derived, mostly for the first time. It is shown that formamide, considered prototypical for the amide linkage, is not typical as it has a planar equilibrium amide linkage corresponding to a single-minimum inversion potential around N. In contrast, several molecules containing the CONH linkage seem to have a pyramidalized nitrogen at equilibrium and a double-minimum inversion potential with a very small inversion barrier allowing for an effectively planar ground-state structure. Observables of rotational spectroscopy, including ground-state inertial defects, quadrupole coupling and centrifugal distortion constants, and dipole moment components, as well as equilibrium C=O and C-N bond lengths are reviewed in their ability to indicate the planarity of the effective and possibly the equilibrium structures.

Original languageEnglish
Pages (from-to)2574-2586
Number of pages13
JournalJournal of Physical Chemistry A
Volume111
Issue number13
DOIs
Publication statusPublished - Apr 5 2007

Fingerprint

linkages
Ground state
Amides
ground state
Urea
Cyanamide
inversions
ureas
Dipole moment
amides
Bond length
cyanamides
Nitrogen
acids
Spectroscopy
Defects
Molecules
ethers
dipole moments
quadrupoles

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Equilibrium vs ground-state planarity of the CONH linkage. / Demaison, Jean; Császár, A.; Kleiner, Isabelle; Møllendal, Harald.

In: Journal of Physical Chemistry A, Vol. 111, No. 13, 05.04.2007, p. 2574-2586.

Research output: Contribution to journalArticle

Demaison, Jean ; Császár, A. ; Kleiner, Isabelle ; Møllendal, Harald. / Equilibrium vs ground-state planarity of the CONH linkage. In: Journal of Physical Chemistry A. 2007 ; Vol. 111, No. 13. pp. 2574-2586.
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