Microwave spectroscopy and structures of two conformers of 1H-heptafluoropropane.
Two conformations of 1,1,2,2,3,3,3-heptafluoropropane (1H-heptafluoropropane, HFP) have been observed and characterized by its microwave rotational spectrum. The HC(1)C(2)C(3) dihedral angle is analogous to the CCCC dihedral angle in butane and exhibits both trans and gauche orientations. Rotational transitions of all three selection rules are observed for the gauche conformer, consistent with C(1) symmetry. Only a- and b-type transitions are observed for the trans form, consistent with a 180 degrees dihedral angle and overall C(s) symmetry. Computed models at the PBE0/VTZ level are in excellent agreement with experimental results. The structures were characterized by scaling the principal coordinates of the computed models to exactly reproduce the observed second moments.
Fournier
Joseph A
JA
Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA.
Bohn
Robert K
RK