title: The C-N rotation barrier of the lithium enolate of acetamide: an ab initio and density functional theory investigation.
abstract: Semiempirical (PM3), ab initio (HF/6-31+G(d) and MP2/6-31+G(d)), and density functional (pBP/DN) calculations are used to investigate the rotation barrier of the carbon-nitrogen bond in a simple enolate anion: lithium acetamide, 1. For comparison, the amidate anion 2, vinylamine 3, and a simulated dimer 4 were also calculated. In all systems, the barrier to rotation was found to be less than 10 kcal x mol(-1) in agreement with experiment. The correlated calculations show the barrier to be lowest for the anion 2. The results show conjugation effects in 1 and 2 comparable to that in vinylamine 3 and imply that polarization effects are more important than charge transfer in amine conjugation.
authors: Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
authors: J K
authors: JK
authors: Pugh
authors: A
authors: A
authors: Streitwieser