Rotational spectroscopy, quadrupole coupling and unusual quartic centrifugal distortion constants of 1,1-dichloro-1-silacyclopent-2-ene

Abstract

The ground state rotational spectrum of 1,1-dichloro-1-silacyclopent-2-ene has been recorded using chirped-pulse Fourier transform microwave spectroscopy. A planar ring-structure in the ground vibrational state is supported by the rotational spectrum, but particularly by the analysis of the sometimes-complicated hyperfine splitting and isotopic substitution. Furthermore, fitting the rotational spectrum to a Watson S-reduced Hamiltonian in the I^r representation yields a negative value of D_J, which is in agreement with quantum chemical calculation. In addition, the quadrupole coupling is considered and some structural information is presented — both compare well to expectations from other related systems and quantum chemical calculation.