Molecular geometry of SO2…ClF from its rotational spectrum: a cis, planar complex with a linear O…ClF bond

The ground-state rotational spectra of SO2…35ClF and O2…37ClF were observed by using a fast-mixing nozzle/pulsed Fourier transform microwave spectrometer combination. Rotational constants, centrifugal distortion constants and the complete Cl-nuclear quadrupole coupling tensor were determined in each case. Interpretation of the spectroscopic constants shows that the complex has a planar geometry with ClF forming a weak bond to one of the O atoms of SO2 [r(O…Cl) = 2.733(11) Å] in a cis arrangement with respect to the SO double bond [φ = 228.4(6)°]. The O…ClF nuclei deviate from collinearity by only θ = −0.7(2)°.