Molecular structure of bis(dimethylamino)difluorosulfurane. The first x-ray crystal structure of a fluorosulfurane

Abstract

Abstract : The molecular structure of (Me2N)2SF2 has been determined by single crystal X-ray diffraction methods. The compound crystallizes in the monoclinic system, space group C2/c, with a = 11.00 (2) A, b = 5.693 (6) A, c = 12.24 (3) A, beta = 92.79 (10) deg., and Z = 4. The symmetry of (Me2N)2SF2 is C2, and the structure is essentially trigonal bipyramidal with the fluorine and Me2N ligands occupying axial and equatorial sites, respectively. The third equatorial site is occupied by the sulfur 'lone pair' which lies along the C2 symmetry axis. Since the dihedral angle between the C-N-C and N-S-N planes is 48.2 deg., the nitrogen lone pairs are disposed approximately midway between the sulfur lone pair and the sulfur-fluorine axial (S-F2) bonds. The sum of the bond angles around the nitrogen atoms is 342.3 deg.; hence the hybridization at these centers is approximately halfway between sp(2) and sp(3). The Fa-S-Fa bonds are bent toward the sulfur lone pair by 5.3 deg., and the equatorial N-S-N bond angle is 102.3(1) deg. The S-F and S-N bond distances are 1.770(2) A and 1.648(2) A, respectively. (Author)