Structural, conformational and vibrational properties of 1,1,1-Trifluoro-N-(1,1,2,2,2-pentafluoroethyl) methanesulfinimidoyl chloride, CF3CF2-N=S(Cl)CF3.

The structural, conformational, and configurational properties of 1,1,1-Trifluoro-N-(1,1,2,2,2-pentafluoroethyl) methanesulfinimidoyl chloride, CF3CF2NS(Cl)CF3 have been studied by vibrational spectroscopy [IR (vapor) and Raman (liquid)] and quantum chemical calculations [B3LYP, MP2 and B3PW91 levels of theory using the 6-311+G(d), 6-311+G(df) and 6-311+G(2df) basis sets]. According to these theoretical approximations, CF3CF2-N=S(Cl)CF3 exists in the gas phase as a mixture of a favored anticlinal form (CN bond anticlinal with respect to the CSCl bisector) with C1 symmetry and a less abundant syn conformer showing C1 symmetry as well (ΔG° ≈ 1.20 kcal mol(-1)). Due to the small contribution only a few corresponding vibrational modes of the syn conformer could be assigned confidently in the experimental spectra. Compared to CF3CF2-N=S(F)CF3, the replacement of F by Cl produces a clear change in NS bond length and the corresponding stretching frequency, without affecting the conformational properties.

Synthesis, characterization and vibrational properties of p-fluorosulfinylaniline.

The reaction of p-fluoroaniline and SOCl2 rendered p-fluorosulfinylaniline in good yield. The obtained dark yellowish liquid compound was characterized by NMR, UV-visible, FT-IR and Raman spectroscopies. The observed features were consistent with the existence of only one conformer, belonging to the CS symmetry group. A tentative assignment of the vibrational modes was performed on the basis of experimental spectra and quantum chemical calculations at different levels of theory (B3LYP and MP2 with 6-31+G(d), 6-311+G(d) and 6-311+G(df) basis sets). The conformational and vibrational properties of p-fluorosulfinylaniline were in good agreement with experimental data reported for other substituted sulfinylanilines and p-halogenanilines.

CF3CF2N=S(F)CF3: vibrational spectra and conformational properties.

The structural, conformational, and configurational properties of 1,1,1-trifluoro-N-(1,1,2,2,2-pentafluoroethyl) methanesulfinimidoyl fluoride, CF3CF2N=S(F)CF3 have been studied by vibrational spectroscopy [IR (vapor) and Raman (liquid)] and quantum chemical calculations [B3LYP, MP2 and B3PW91 levels of theory (using the 6-311+G(d) and 6-311+G(2df) basis sets). According to these theoretical approximations, CF3CF2N=S(F)CF3 might be found in the gas phase as a mixture of a favoured anticlinal form (C-N bond anticlinal with respect to the C-S-F bisector angle) and a less abundant syn conformer showing C1 symmetry as well (ΔG°≈1.5 kcal mol(-1)). However, corresponding vibrational modes for these conformers show only small shifts which would not allow confidently detecting the rather small contribution of this second form in the experimental spectra.

((Fluoroformyl)imido)sulfuryl difluoride, FC(O)N=S(O)F2: structural, conformational, and configurational properties in the gaseous and condensed phases.

Structural, conformational, and configurational properties of the gaseous molecule ((fluoroformyl)imido)sulfuryl difluoride, FC(O)N=S(O)F(2), have been studied by vibrational spectroscopy (IR (gas) and Raman (liquid)) and quantum chemical calculations (HF, MP2, and B3LYP with 6-31+G* and 6-311+G* basis sets); in addition, the solid-state structure has been determined by X-ray crystallography. FC(O)N=S(O)F(2) exists in the gas phase as a mixture of a favored antiperiplanar-synperiplanar form (the S=O double bond antiperiplanar with respect to the C-N single bond, and the C=O group synperiplanar with respect to the S=N double bond) in equilibrium with less abundant antiperiplanar-antiperiplanar, synclinal-synperiplanar, and synclinal-antiperiplanar structures. The crystalline solid at 163 K (monoclinic, P2(1)/c, a = 5.1323(7) A, b = 15.942(2) A, c = 16.798(2) A, beta = 95.974(3) degrees , Z = 12) consists of three similar antiperiplanar-synperiplanar forms.

Vibrational spectra and gas-phase structure of N-methyl-S,S-bis(trifluoromethyl)sulfimide, CH3N=S(CF3)2.

The molecular structure of N-methyl-S,S-bis(trifluoromethyl)sulfimide, CH3N=S(CF3)2, was determined by gas electron diffraction and quantum chemical calculations [B3LYP and MP2 with 6-31+G(2df,p) basis sets]. Furthermore, vibrational spectra, IR (gas) and Raman (liquid), were recorded. These spectra were assigned by comparison with analogous molecules and with calculated frequencies and intensities (HF, B3LYP, and MP2 with 6-311G basis sets). All experimental data and computational methods result in a single conformer with syn orientation of the CH3 group relative to the bisector of the two CF3 groups. The molecule possesses C1 symmetry, slightly distorted from CS symmetry. The N=S bond length in this compound [1.522(10) A] is longer than that in imidosulfur difluorides RN=SF2 [1.476(4) A - 1.487(5) A].