The conformation of 3,4-dihydro-2H-1,5-benzodioxepin-2,4-dicarboxylic acid
Abstract
The crystal structure of 3,4-dihydro-2H-1,5-benzodioxepin-2,4-dicarboxylic acid has been determined by X-ray diffration methods clearly demonstrating that the molecular conformation is skew (twisted half-chair), the skew twist angle being approximately 40°. The space group symmetry (Pbcn) and four molecules in the unit cell unequivocally eliminate the possibility of the chair conformation deduced from the ultraviolet absorption spectra of solutions in methanol. The apparent discrepancy is discussed in terms of the assumptions upon which the latter method was based.
- Publication:
-
Journal of Molecular Structure
- Pub Date:
- August 1973
- DOI:
- 10.1016/0022-2860(73)85176-2
- Bibcode:
- 1973JMoSt..17..355S