Gas phase structure of ((fluoroformyl)imido)sulfuryl difluoride, FC(O)N=S(O)F2

Abstract

The geometric structure and conformational properties of gaseous ((fluoroformyl)imido) sulfuryl difluoride, FC(O)N{double bond, short}S(O)F2, was investigated by gas electron diffraction (GED) and quantum chemical methods (MP2 and B3LYP with 6-31G(d) and 6-311+G(2df) basis sets). In combination with earlier reported infrared spectra, the GED study results in a mixture of at least three conformers, 71(10)% syn(N{double bond, short}S)-syn(N-C), 14(8)% anti(N{double bond, short}S)-syn(N-C) and 15(5)% syn(N{double bond, short}S)-anti(N-C). Syn(N{double bond, short}S) or anti(N{double bond, short}S) implies synperiplanar or anticlinal orientation of the FC(O) group with respect to the SF2 bisector and syn(N-C) or anti(N-C) implies synperiplanar or antiperiplanar orientation of the C{double bond, short}O bond with respect to the N{double bond, short}S bond. The anti(N{double bond, short}S)-anti(N-C) conformer has not been observed, but a small amount (<5%) cannot be excluded. These conformational properties are well reproduced by quantum chemical calculations with small basis sets and the geometric parameters are reproduced satisfactorily with large basis sets.