Microwave spectroscopy and characterization of the helical conformer of perfluorohexane

Abstract

The lowest energy conformer of perfluorohexane (C 6 F 14 ) is helical and its microwave rotational spectrum has been observed and assigned. The helicity along the carbon chain results in overall C 2 symmetry with the C 2 axis corresponding to the c-principal axis. The assignment of a c-type spectrum confirms the structure of C 6 F 14 to be helical. The rotational constants are A 824.9001(9) MHz, B 202.2195(8) MHz, and C 198.3355(10) MHz. The molecular parameters were characterized by scaling computed models by the square root of the ratio of the observed second moments to those computed. The scaled structures exactly reproduce the observed second moments. From this scaling approach, the exterior C 1 C 2 C 3 C 4 dihedral angle is 16.