Theoretical Study of Internal Rotation in Perfluorobutadiene
Journal of Molecular Structure
Semiempirical and ab initio molecular orbital methods, including full geometry optimizations, are used to study the rotational profile about the central CC bond of perfluorobutadiene. The MNDO method yields a rather flat potential with a minimum of 109°, corresponding to a nearly perpendicular arrangement of the two CC bonds. The potential calculated by both PRDDO and ab initio with a minimal STO-3G basis set contains two minima. One of these is a nonplanar cisoid type structure corresponding to the experimentally observed conformation. Slightly lower in energy is a planar structure with the two double bonds trans to one another.
Theoretical Study of Internal Rotation in Perfluorobutadiene T. Choudhury and S. Scheiner J. Mol. Struct., Theochem., 1984 18, 373-379.