Über die Umsetzung von NN-Dihalogenperfluoralkanaminen mit Schwefel und Schwefelderivaten

Reactions of NN-Dihaloperfluoroalkaneamines with Sulfur and Sulfur Derivatives Reactions of NN-Dihaloperfluoroalkaneamines R_fNX₂ (R_f = CF₃, C₂F₅; X = Cl, Br) with S₈, S₄N₄ and A = SX₂ (A = R_fN, O) are described. The products isolated are: Sulfurdihalideimides R_fNSX₂ (R_f = CF₃, C₂F₅; X = Cl, Br), Sulfurdiimides R_fNSNR_f and Bis(sulfurdiimido)sulfides (R_fNSN)₂S(R_f = CF₃, C₂F₅). Thionylimides R_fNSO were not obtained in preparative quantities.     

Arylthiazylamides: syntheses, structures, and bonding properties

Air-sensitive, thermally unstable tris(dimethylamino)sulfonium (TAS) salts (3) of the title anions [ArNSN]- have been prepared from corresponding sulfurdiimides Ar-N=S=N-SiMe3 (2) by Si-N bond cleavage with [(Me2N)3S]-[Me3SiF2]- (TASF). They are characterized by low-temperature X-ray crystallography as Z isomers. Because of the very short terminal S-N distance (144.2 (3h)-147.9 (3i)pm) and the relatively long internal S-N distance (158.3 (3i)-160.3 (3c) pm) the [ArNSN]- ions should be regarded as thiazylamides 1b, rare species containing a S triple bond N triple bond. A bonding model is developed and the experimental results are compared with those of restricted Hartree-Fock (RHF), density functional theory (DFT), and M?ller-Plesset second-order (MP2) calculations.     

Pentafluorsulfanylamine und Sulfanylammonium-Salze

Pentafluorosulfanylamines and Sulfanylammonium Salts . From the addition of HF to sulfurtetrafluorideimides N-alkylpentafluorosulfanylamines RNHSF₅(2a, 2b: R=CH₃, C₂H₅) are obtained in quantitative yield. N, N-dialkylpentafluorosuIfanylamines Et₂NSF₅(5a) and pip-SF₅ (5b) are isolated from the reaction of the appropriate sulfurdifluoronitridearnides NSF₂NR₂ and HF/SF₄. Protonation of the amines with the superacidic system HF/AsF₅ gives stable pentafluorosulfanyl-ammonium salts SF₅NHRR′_. AsF₆ (12: R = R′ = CH₃; 14: R=R′=H; 10: R=CH₃, R′ = H). Under the same conditions the adduct AsF₅· NSF₂CF(CF₃)₂ (15) forms a cation with hexacoordinated sulfur (trans-H₃NSF₄CF(CF₃)₂^?AsF₆⁶: 16), while with Asp₅ · NSF₂NMe₂ (17) the reaction stops at tetracoordination (HNSF₂NMe₂⁺AsF₆ : 18).     

Structure of the SO(2)F(-) anion, a problem case

Recently, room-temperature crystal structures of SO(2)F(-) in its K(+) and Rb(+) salts were published in Z. Anorg. Allg. Chem. 1999, 625, 385 and claimed to represent the first reliable geometries for SO(2)F(-). However, their almost identical S-O and S-F bond lengths and O-S-O and O-S-F bond angles are in sharp contrast to the results from theoretical calculations. To clarify this discrepancy, the new [(CH(3))(2)N](3)SO(+) and the known [N(CH(3))(4)(+)], [(CH(3))(2)N](3)S(+), and K(+) salts of SO(2)F(-) were prepared and their crystal structures studied at low temperatures. Furthermore, the results from previous RHF and MP2 calculations were confirmed at the RHF, B3LYP, and CCSD(T) levels of theory using different basis sets. It is shown that all the SO(2)F(-) salts studied so far exhibit varying degrees of oxygen/fluorine and, in some cases, oxygen-site disorders, with [(CH(3))(2)N](3)SO(+)SO(2)F(-) at 113 K showing the least disorder with r(S-F) - r(S-O) = 17 pm and angle(O-S-O) - angle(F-S-O) = 6 degrees. Refinement of the disorder occupancy factors and extrapolation of the observed bond distances for zero disorder resulted in a geometry very close to that predicted by theory. The correctness of the theoretical predictions for SO(2)F(-) is further supported by the good agreement between the calculated and the experimentally observed vibrational frequencies and their comparison with those of isoelectronic ClO(2)F. A normal coordinate analysis of SO(2)F(-) confirms the weakness of the S-F bond with a stretching force constant of only 1.63 mdyn/A and shows that there is no highly characteristic S-F stretching mode. The S-F stretch strongly couples with the SO(2) deformation modes and is concentrated in the two lowest a' frequencies.     

Fluoride ion transfer and stabilisation of reactive ions

Some general guidelines for the generation of salts with high fluoride ion donor ability are discussed. A preliminary scale for a limited number of fluoride ion donors is presented, cations are classified according to their anion-cation interaction properties. Examples for fluoride ion transfer reactions are given and the influence of anion-cation interaction on the stabilisation of reactive anions is discussed. In our work mainly TAS fluoride (Me₂N)₃S⁺Me₃SiF₂⁻ has been used as fluoride ion source: (a) for fluoride ion transfer to coordinatively unsaturated sulfur species, to SN and SO multiple bond systems, to SN, PN and CN heterocycles, (b) for the stabilisation of primary products of nucleophilic attacks and of intermediates in isomerisation processes or of intermediates in polymerisation processes, (c) for the generation of “naked” anions by silicon-element bond cleavage, and (d) for the activation of element-fluorine bonds by anion formation.     

Insertion-reaction of fluorinated methylenes into the S(II)Cl bond

(CF₃)₂CN₂ (1) and CF₃CHN₂ (4) react with (CF₃)₂CNSCl (2) to give (CF₃)₂CNSCCl(CF₃)₂ (3) and (CF₃)₂CNSCHClCF₃ (5) respectively. From (4) and (NSCl)₃ CF₃CHNSCHClCF₃ (6) and

(8) are obtained.