Ab initio study of intramolecular proton transfer in formohydroxamic acid

Deng Hwa Wu, Jia-Jen Ho

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

Interconversion of five isomeric tautomers of formohydroxamic acid via intramolecular proton transfer has been examined by ab initio theoretical calculation. The transfer potential surfaces, the global isomeric structures, and the transition geometries of intramolecular proton transfer were determined by the MP2/6-31+G** level of calculation. The energy was further analyzed by a single point calculation, MP2/6-31++G**//MP2/6-31+G**, and the use of G2 theory. Not counting the unstable charge separating species, the order of stability of these tautomers calculated at the HF level was 1E > 1Z > 2Z > 2E, and it shifted to 1Z > 1E > 2Z > 2E at the MP2 level, where 1Z and 1E are keto forms, while 2Z and 2E are iminol forms. Further investigation using G2 theory redirects the order to be 1Z > 2Z > 1E > 2E. The strength of the intramolecular hydrogen bond and the effect of dipole moment are the two major factors to dominate the acidity of formohydroxamic acid. Judging from the transition barrier of intramolecular proton-transfer we believe that formohydroxamic acid in dissociating proton in the gas phase is an N-acid.

Original languageEnglish
Pages (from-to)3582-3586
Number of pages5
JournalJournal of Physical Chemistry A
Volume102
Issue number20
DOIs
Publication statusPublished - 1998 May 14

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Proton transfer
Protons
acids
protons
tautomers
Dipole moment
Acidity
Hydrogen bonds
Gases
acidity
Hydrogen
counting
dipole moments
Acids
Geometry
vapor phases
hydrogen bonds
formohydroxamic acid
geometry
energy

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Ab initio study of intramolecular proton transfer in formohydroxamic acid. / Wu, Deng Hwa; Ho, Jia-Jen.

In: Journal of Physical Chemistry A, Vol. 102, No. 20, 14.05.1998, p. 3582-3586.

Research output: Contribution to journalArticle

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