Weak CH⋅⋅⋅F Bridges and Internal Dynamics in the CH3F⋅CHF3 Molecular Complex

A preferred conformation of the internally highly dynamic fluoromethane–trifluoromethane molecular complex results from the stabilization of the two subunits by three weak CH⋅⋅⋅F hydrogen bonds and electrostatic dipole–dipole interactions (see picture). The two subunits are not rigidly locked, but exhibit large amplitude motions by almost freely spinning around their symmetry axes as shown.