Christiane Leibold

Structure and conformation of fluoroformyliminosulfur difluoride, FC(O)NSF2

Abstract The conformational properties and the geometric structure of fluoroformyliminosulfur difluoride, FC(O)NSF 2 , were studied in the gas phase by vibrational spectroscopy and by joint analysis of gas electron diffraction (GED) intensities and rotational constants from the literature. Only one planar cis-syn conformation, with the FC(O) group cis to the SF 2 group and the CO double bond syn to the NS double bond, is observed. The contribution of any other conformer is estimated to be ⩽ 3%. The following skeletal geometric parameters ( r z values, estimated uncertainties are 2σ values) were derived: S  N = 1.479 (4) A , N  C = 1.395 (6) A , S  F = 1.586 (2) A , CNS = 126.7 (11)°, NSF = 110.4 (8)°, FSF = 93.4 (3)°. These geometric parameters are well reproduced by HF/6-31G∗ ab initio calculations.

Gas phase structures of trifluoroacetyl chloride, CF3C(O)CL, and chlorodifluoroacetyl chloride, CF2ClC(O)Cl

Abstract The geometric structures of trifluoroacetyl chloride, CF 3 C(O)Cl, and chlorodifluoroacetyl chloride, CF 2 ClC(O)Cl were determined by gas electron diffraction. The CF 3 group in CF 3 C(O)Cl adopts an eclipsed orientation relative to the C=O double bond. In the predominant conformer of CF 2 ClC(O)Cl (93(3)%) the two chlorine atoms are gauche to each other (Θ(ClCCCl) = 75.4(10)°) with a small contribution of the trans form (Θ(ClCCCl) = 180°). The experimental geometric parameters are compared to those obtained by ab initio calculations.