Conformational Equilibrium in 1-Fluoro-1-silacyclobutane as Studied by Microwave Spectroscopy and ab Initio Calculations

The microwave spectrum of 1-fluoro-1-silacyclobutane has been investigated in the frequency range 26-40 GHz. The spectra of the equatorial and axial conformers and of several vibrational satellites, mainly belonging to the ring-puckering progression, have been assigned. The shifts of the rotational constants with respect to the ground state, together with the relative intensities and the dipole moments, have been used to obtain the shape of the potential energy function hindering the ring-puckering. The experimental results agree well with 6.31G* calculations.