INTERNAL-ROTATION IN BIACETYL - THEORETICAL-STUDY

The internal rotation about the central C-C bond in biacetyl has been investigated using both semiempirical and ab initio molecular orbital techniques. The results indicate that, while both trans and cis conformers can exist, the latter is present to less than % at room temperature. This result is in agreement with experimental studies in which only the trans conformer was observed. The highest occupied molecular orbitals are the na, πb, nb, and πa orbitals in order of increasing Koopmans' theorem ionization potentials. © 1979, American Chemical Society. All rights reserved.