Formaldehyde oxime ⇌ nitrosomethane tautomerism

J. A. Long, N. J. Harris, K. Lammertsma

Research output: Contribution to journalArticlepeer-review

76 Citations (Scopus)


Formaldehyde oxime ⇌ nitrosomethane tautomerism, isomeric nitrone, and their common cations and anions are studied with Gaussian-2 theory using MP2(full)/6-31G* geometries and with density functional theory using B3LYP/6-311+G**. Geometrical parameters, harmonic vibrational frequencies, relative stabilities, conformational stabilities, and ionization energies are compared with experimental gas-phase data when available. The formaldehyde oxime ⇌ nitrosomethane tautomerism is compared with the amide ⇌ imidol, imine ⇌ enamine, keto ⇌ enol, and nitro ⇌ aci-nitro tautomeric processes. Solvent effects are estimated by the self-consistent isodensity polarizable continuum model (SCIPCM). The influence of hydrogen bonding interactions with the solvent is addressed by including two water molecules. In the final evaluation, formaldehyde oxime is 15.8 kcal/mol more stable than nitrosomethane when the aqueous solvation correction of 3.8 kcal/mol is applied to the G2 energies. Unsolvated formaldehyde oxime is estimated to be 11.1 kcal/mol more stable than nitrone. The estimated gas-phase ionization energies (G2) are 362.5 kcal/mol for formaldehyde oxime, 350.6 kcal/mol for nitrosomethane, and 351.4 kcal/mol for nitrone.

Original languageEnglish
Pages (from-to)6762-6767
Number of pages6
JournalJournal of Organic Chemistry
Issue number20
Publication statusPublished - 5 Oct 2001
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry


Dive into the research topics of 'Formaldehyde oxime ⇌ nitrosomethane tautomerism'. Together they form a unique fingerprint.

Cite this