Does Perdeuteration Increase the Polarity of Janus Face Cycloalkanes?

Stimulated by a suggestion of the late Professor Jack D. Dunitz, that perdeuterated Janus face cycloalkanes may be more polar than their unlabelled forms, deuterated isotopologue all cis-1,2,3,4,5,6-hexafluorocyclohexane ([2H6]-1a) and cis-1,2,3,4-tetrafluorocyclopentane ([2H6]-3a) were prepared. Computation at B3LYP−D3 level indicated [2H6]-1a is not its protio form 1, however cyclopentane [2H6]-3a indeed 3, although magnitude predicted to small. None-the-less retention time analysis on reverse phase GC/MS column an add-mix 3 gave some indication per-deuterated 3a was detected marginally before compound consistent with increased polarity associated perdeuteration.