Particularly strong C-H···π interactions between benzene and all-cis 1,2,3,4,5,6-hexafluorocyclohexane.

We present the first high-level ab initio benchmark study of the interaction energy between fluorocyclohexanes and benzene. These compounds form CH···π interactions with aromatic solvents which causes notable shielding of the axial cyclohexane protons. For the recently synthesised all-cis 1,2,3,4,5,6-hexafluorocyclohexane the interaction energy with benzene amounts to -7.9 kcal mol(-1) and -6.4 kcal mol(-1) at the MP2 and SCS-MP2 levels, respectively (extrapolated to the complete basis set limit), which according to dispersion-corrected density functional calculations, is largely due to dispersion.