Concerning the electronic and geometric structure of bromodifluoroacetonitrile, CBrF₂CN

The pure rotational spectrum of bromodifluoroacetonitrile between 7.7 and 18 GHz has been measured on a chirped pulse microwave spectrometer. The spectra are dense with 889 measured transitions in the region. Rotational, centrifugal distortion, nuclear electric quadrupole coupling constants (⁷⁹Br, ⁸¹Br, and ¹⁴N), and nuclear magnetic spin-rotation constants (⁷⁹Br/⁸¹Br) were determined and are reported for the first time. Quantum chemical calculations were made of the nuclear quadrupole coupling constants to assist with assignment of the spectra. Spectra from both ¹³C isotopologues were measured in natural abundance. The effects of flourination on the nuclear electric quadrupole coupling tensor components for the series of monobrominated acetonitrile molecules are discussed.