Configuration at oxygen and deviation of the O…ClF system from linearity in 2,5-dihydrofuran…ClF from rotational spectroscopy

Rotational spectra of two isotopomers of the 2,5-dihydrofuran/ClF complex were observed by using the fast-mixing nozzle/Balle-Flygare spectrometer combination. The complex has Cs symmetry and a pyramidal configuration at oxygen. The angle between the 35ClF axis (z) and the a-axis, αaz = 17.95(3)°, was determined from the Cl nuclear quadrupole coupling tensor. The geometry r(O…Cl) = 2.422(5) Å, θ = 127.0(3)° and θ = 1.99(15)° is established when rotational constants are fitted under the constraints of unperturbed monomers and αaz = 17.95(3)°. the configurations θ at O and the nonlinearities θ of the B…ClF/B…HCl systems are compared for B = 2,5-dihydrofuran and oxirane.