AN INVESTIGATION OF THE MICROWAVE SPECTRUM AND MOLECULAR STRUCTURE OF SULFONYL CHLORIDE ISOCYANATE

$^{1}$Brunvall, J. and I. Hargittai, J.C.S. Dalton, 299 (1978).""Author Institution: Dept. of Chemistry, Virginia Polytechnic Institue and State University; Molecular Physics Division, National Institute of Standards and TechnologyAn electron diffraction $study^{1}$ of sulfonyl chloride isocyanate, $SO_{2}ClNCO$, could not make a definitive choice between the system being a single isomer with an SCl-NC dihedral angle of $94^{0}$ or a mixture of two isomers having angles of $71^{0}$ and $110^{0}$. The microwave spectrum of $SO_{2}ClNCO$ has been investigated between 7 GHz and 26 GHz using both a conventional Stark spectrometer and a Fourier transform spectrometer. The spectra of two isotopic species ($^{35}Cl$ and $^{37}Cl$) were assigned and the rotational constants and the nuclear quadrupole coupling constants for $^{35}Cl$, $^{37}Cl$ and $^{14}N$ were determined. Using the six rotational constants derived from the assignment and parameters relating the $-SO_{2}$ moiety structure from the electron diffraction study and other studies of molecules containing the $SO_{2}$ group, the dihedral angle was found to be $93.86^{0}$ (12) and the $\angle NCO=175.68(6).$ This study indicates the existence of only a single isomer at the temperature of the Fourier spectrometer experiment and a nonlinearity of the NCO group as has been observed in other similar systems. The value obtained for $^{35}Cl$, $X_{zz} -71.6 MHz$ indicates a $S-Cl$ bond ionicity of 35\%