Hans Georg Mack

Structures and conformational properties of trifluoromethylsulfonyl isocyanate, CF3SO2NCO, and trifluoromethylsulfonyl azide, CF3SO2N3

Abstract The geometric structures of trifluoromethylsulfonyl isocyanate, CF 3 SO 2 NCO, and trifluoromethylsulfonyl azide, CF 3 SO 2 N 3 , have been determined by gas electron diffraction and by theoretical methods ( HF 6–31 G ∗ , HF 6–31 G ∗ , MP 2 6–31 G ∗ , B 3 P 91 6–31 G ∗ . Both compounds possess a single conformation with eclipsed or nearly eclipsed orientation of the NCO or N 3 group relative to one Sue5fbO double bond and dihedral angles o (Oue5fbSue5f8Nue5fbC) = 4(8)° and o (Oue5fbSue5f8Nue5fbN) = − 24(6)°. The negative sign indicates that the azide group is rotated towards the CF 3 group. The Sue5f8N bonds in both compounds are very similar (1.653(5) and 1.668(4) A, respectively). The nitrogen bond angle in the isocyanate (Sue5f8Nue5fbC = 126.5(15)°) is larger by 15° than that in the azide (Sue5f8Nue5fbN = 111.6(15)°). All theoretical methods reproduce the experimental structures satisfactorily except for the Sue5f8C and Sue5f8N bond lengths.

Gas-phase structures of trans-disubstituted SF6 derivatives: CF3SF4CF3, CF3SF4Cl and CF3SF4CH3

Abstract The geometric structures of the trans -disubstituted SF 6 derivatives CF 3 SF 4 CF 3 , CF 3 SF 4 Cl and CF 3 SF 4 CH 3 have been determined by gas electron diffraction. The equatorial Sue5f8F bond lengths ( r a values) of 1.592(2), 1.583(2) and 1.606(3) A, respectively, are compared with the values in the monosubstituted compounds SF 5 CF 3 and SF 5 Cl.