The rotational spectrum and structure of the hydrogen-bonded dimer formed between methylenecyclopropane and HF

The hydrogen-bonded dimer between methylenecyclopropane and HF was observed and its rotational spectrum measured with a pulsed-nozzle Fourier-transform microwave spectrometer. Simultaneous analysis of the spectroscopic constants of HF and DF species of the dimer shows that the acid is attached in a T-type configuration to the double bond of methylenecyclopropane in or near to, the σν mirror plane that bisects the ring. The tilt of the HF moiety in this plane towards the ring can be included by ascribing a departure from linearity of 12° to the hydrogen bond.