Interaction between Freons and Amines: The C–H···N Weak Hydrogen Bond in Quinuclidine–Trifluoromethane

The 1:1 complex between quinuclidine and trifluoromethane has been investigated using pulsed jet Fourier transform microwave spectroscopy. The two constituting molecules are held together through a weak C−H···N hydrogen bond, with a H···N length of 2.070(1) Å. The C3 symmetric axes of the two moieties are collinear, making the overall molecular system a symmetric top. The HCF3 subunit is freely rotating with respect to the amine moiety. Transitions for the ground (m = 0) and for the first excited (|m| = 1) torsional states, with K up to 2, have been measured, all of them showing the 14N nuclear quadrupole hyperfine structure. The dissociation energy of the complex has been estimated to be 10.2 kJ mol−1