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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Conformational preferences for N,N-dimethyl-2-haloacetamides (halo= F, Cl, Br and I) through theoretical and experimental studies: An unexpected orbital interaction

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Author(s):
Martins, Carina R. ; Rittner, Roberto ; Tormena, Claudio Francisco [3]
Total Authors: 3
Document type: Journal article
Source: JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM; v. 728, n. 1/3, p. 79-84, Sept. 2005.
Field of knowledge: Physical Sciences and Mathematics - Chemistry
Abstract

Conformational preferences and orbital interactions of N,N-dimethyl-2-fluoroacetamide (1), N,N-dimethyl-2-chloroacetamide (2), N,Ndimethyl-2-bromoacetamide (3) and N,N-dimethyl-2-iodoacetamide (4) were analyzed using experimental infra-red data, theoretical calculations and NBO analysis. The conformational equilibria of compounds 1-4 can be represented by their cis and gauche rotamers. The gauche form of I is stable in the vapor phase and in a non-polar solvent, but the cis is predominant in a polar solvent. For 2-4 the gauche form is more stable than the cis, in both the vapor and liquid phases. These conformational preferences were attributed to the orbital interaction between two antibonding orbitals, pi*(C=O)->sigma*(C-X). This unexpected interaction was possibly due to the high (0.3) electron density on pi*C=O, which results from the interaction between one nitrogen lone pair and pi*C -> O. (AU)

FAPESP's process: 00/07692-5 - Conformational equilibria studies by nuclear magnetic resonance spectroscopy, infrared spectroscopy and theoretical calculations
Grantee:Roberto Rittner Neto
Support Opportunities: Research Projects - Thematic Grants