Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9591091 | Journal of Molecular Structure: THEOCHEM | 2005 | 6 Pages |
Abstract
Conformational preferences and orbital interactions of N,N-dimethyl-2-fluoroacetamide (1), N,N-dimethyl-2-chloroacetamide (2), N,N-dimethyl-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 1 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, Ï*COâÏ*C-X. This unexpected interaction was possibly due to the high (0.3) electron density on Ï*CO, which results from the interaction between one nitrogen lone pair and Ï*CO.
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Authors
Carina R. Martins, Roberto Rittner, Cláudio F. Tormena,