Reactions of Fluorinated Nitriles with Sulphur(II) Chlorides; Crystal Structure of 2,4,6-Tris(difluorosulphoximido)-l,3,5-triazene at 170 K Hans-Ulrich Höfs, Rüdiger Mews*, Mathias Noltemeyer, George M. Sheldrick, and Martin Schmidt Institut für Anorganische Chemie der Universität, Tammannstraße 4, D-3400 Göttingen Gerald Henkel and Bernt Krebs Institut für Anorganische Chemie der Universität, Gievenbecker Weg 9, D-4400 Münster Z. Naturforsch. 38b, 454-459 (1983); eingegangen am 8. November 1982 Crystal Structure, Perfluoromethanesulphenylformylimidoylchlorides, N-Sulphenylchlorides, 1,3,5 -Triazenes The addition of CF3SC1 (2) to the fluorinated nitriles Rf CN[Rf = CF3 (3), NSF2 (4), NSOF2 (5)] leads to N-perfluoromethanesulphenyl-formylimidoylchlorides CF3S-N = C(C1)/?/ (6, 11, 12). From the reactions of SC12 (1) with (3) and (5), which yielded the N-sulphenyl- chlorides C1S-N = C(C1)-R/ (7, 13), it proved possible also to isolate the oxidation product [CF3CC12NSC12 (8)] and an oligomer of the nitrile [(NCNSOF2) 3 (14)]. Dechlorination of 7 with Hg gives the corresponding di- and tri-sulphides (CF3C(Cl) = N-)2Sa; (9, 10, x — 2, 3). Crystals of (14) are triclinic with a = 1133.6(5), b = 1332.6(5), c = 1715.1(8) pm, a = 109.31(3), ß = 105.30(3), y = 97.84(3)° at 170 K, Z = 8, space group P I. The structure was refined to R = 0.028 for 8290 diffractometer data with F > 4cr(F). The four crystallo- graphically independent molecules adopt similar unsymmetrical conformations. N-Sulphenylacetimidoyl halides of the type RC(X)=N-S-Y are important in preparative chem- istry for several reasons: (a) When Y is a halogen, it may be readily exchanged, leading to a chemistry analogous to that of the perhaloalkylsulfenylhalides RhaiSCl [1, 2]. Examples of such substitution reac- tions have already been reported [2, 3], (b) When the substituent X on the triply-coordinated carbon is a halogen, the -M effect of the imino-nitrogen facilitates nucleophilic attack. Hard nucleophiles (fluoride, alcohols, amines) tend to replace X [4], soft nucleophiles the sulphur-substituent Y. (c) The >C=N-S-system may be regarded as a shortened diene, in which the second double bond is replaced by the oxidisable sulphur atom; instead of the usual 1,4-addition this results in 1,3-addition with simul- taneous oxidation of the sulphur [5]. One of the simplest examples of this class of com- pounds , chlorosulphenylchloroformylimidoylchloride may be prepared in several ways; the synthesis [6] from C1CN and SC12 opens a general route to the N-sulphenylimidoyl derivatives [4, 7-9]: C1CN + SC12 C1S-N=CC1 2 1 RCN + R'SCl -> R'S-N=CC1R 2 * Reprint requests to Prof. R. Mews. 0340-5087/83/0400-0454/$ 01.00/0 We report here an investigation of the corresponding addition of CF3SCI and SC12 to the fluorinated nitriles N = C-CF 3 , N = C-NSF 2 and N = C-NSOF 2 . Experimental Starting materials were prepared according to literature methods: SC12 (1) [10], CF3SCI (2) [11], CF 3 CN (3) [12], NCNSF 2 (4) [13], and NCNSOF 2 (5) [14]. IR spectra were recorded on Perkin-Elmer 325 and 180 grating spectrometers, mass-spectra with a Varian MAT CH5 instrument at 70 eV ionisation voltage. CFCI3 was employed as solvent and internal standard for the 19 F NMR measurements, which were obtained on a Bruker 60 E spectrometer. Vapour pressure and derived data were calculated from about 10 data points per sample. Preparation of CF3C(Cl)=N-SCF3 (6) 15.8 g (0.166 mol) 3 and 21.9 g (0.160 mol) 2 were condensed on ca. 0.5 g active carbon in a steel auto- clave. After shaking for 5 d at 20 °C, the volatile products were fractionated under oil-pump vacuum. 6 condensed in the—95 °C trap; the IR and 19 F N M R spectra were identical to those previouslv reported. Yield 30.5 g (0.132 mol) = 82%. Preparation of CF3C(Cl)=N-SCl (7) 3 g active carbon, 15.8 g (0.166 mol) 3 and 20.9 g (0.203 mol) 1 were shaken at 40 °C for 2 d in a steel autoclave until the pressure dropped to below 3 bar. If the reaction ceases prematurely, the active carbon must be renewed. The mixture was fractionated through a 30-cm -Vigreux-column under rough vacuum. Yield 19.9 g (0.101 mol) = 61%. For