Oximes in the isoxazolone, pyrazolone, and 1,2,3-triazolone series: experimental and computational investigation of energies and structures of e/z isomers of α-oxo-oximes in the gas phase and in solution

Koch, Rainer, Wollweber, Hans-Joachim and Wentrup, Curt (2015) Oximes in the isoxazolone, pyrazolone, and 1,2,3-triazolone series: experimental and computational investigation of energies and structures of e/z isomers of α-oxo-oximes in the gas phase and in solution. Australian Journal of Chemistry, 68 9: 1329-1335. doi:10.1071/CH15095


Author Koch, Rainer
Wollweber, Hans-Joachim
Wentrup, Curt
Title Oximes in the isoxazolone, pyrazolone, and 1,2,3-triazolone series: experimental and computational investigation of energies and structures of e/z isomers of α-oxo-oximes in the gas phase and in solution
Journal name Australian Journal of Chemistry   Check publisher's open access policy
ISSN 1445-0038
0004-9425
Publication date 2015-04-29
Sub-type Article (original research)
DOI 10.1071/CH15095
Open Access Status Not Open Access
Volume 68
Issue 9
Start page 1329
End page 1335
Total pages 7
Place of publication Clayton, VIC, Australia
Publisher C S I R O Publishing
Collection year 2016
Language eng
Formatted abstract
The structures of a series of heterocyclic α-oxo-oximes, viz. 4-oximinoisoxazolone-5(4H)-ones 1 and 2,4-oximino-5(4H)-pyrazolones 3–5, and 4-oximino-1-phenyl-1,2,3-triazol-5(4H)-one 6, were investigated experimentally and computationally. Whereas the intramolecularly H-bonded ZZ isomers of these oximes are usually the most stable in the gas phase, this preference is overcome by intermolecular H-bonding to a solvent or another molecule. For 1,3-dimethyl-4-oximino-5(4H)-pyrazolone 3b a turnaround is seen when going from the solid (predominantly Z isomer) to DMSO solution (predominantly E isomer), which can be ascribed to an intermolecular H-bond between the oxime OH function and a DMSO molecule. Such isomerization is not seen in CDCl3, where intermolecular H-bonding is unimportant. The Z/E-isomerization in DMSO solution is accelerated by photolysis. Calculations of the energies of different conformers, and of 13C NMR data at the GIAO-ωb97xD/6-31G(d)//M06-2X/6-311++G(d,p) level permit a clear-cut correlation of conformer structures with observed 13C NMR spectra.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Chemistry and Molecular Biosciences
 
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