Carl J. Schack

On the syntheses and properties of some hexafluorobismuthate (V) salts and their in the metathetical synthesis of NF+4 salts

Abstract The salts LiBiF6, NaBiF6, KBiF6, CsBiF6 and NF4BiF6 were prepared and characterized. Differences in the observed numbers and relative intensities of some of the Raman bands of these salts are explained by crystal effects. Solubilities of these salts in anhydrous HF at -78° were determined and compared to those of the corresponding SbF-6salts. It was shown that, contrary to a previous report, CsBiF6 does not exhibit any unusual properties such as forming a mushy volatile HF adduct. The potential of NF4BiF6 based metathetical processes for the production of other NF+4 salts was evaluated. The novel H3O+BiF-6salt was prepared and characterized. The usefulness of BiF5 for water removal from HF is briefly discussed.

Vibrational spectra of the pseudotrigonal bipyramidal tetrafluorides SF4 and CIF4

Abstract The Raman spectra of gaseous, liquid and solid SF 4 have been re-examined. Polarization measurements allow the unambiguous identification of the A 1 modes. The i.r. spectrum of SF 4 isolated in N 2 matrix has been recorded and 32 S 34 S isotopic shifts have been measured for several fundamentals. The matrix isolation study indicates that the 353 cm −1 absorption consists of two fundamentals, thus providing the hitherto missing ninth fundamental of SF 4 . Complete assignments are given for SF 4 and are supported by force field and mean amplitudes of vibration computations. The results from the vibrational analysis support an intramolecular Berry-type exchange mechanism for SF 4 . Raman polarization data have also been obtained for CIF 4 + SbF 6 − in HF solution and revised assignments and force field values are given for CIF 4 + .

The CF3O− anion: Vibrational spectrum of an unusual CF3 compound

Abstract The i.r. and Raman spectra of solid CsOCF 3 and the Raman spectra of liquid and gaseous NF 3 O have been recorded. The vibrational spectrum of CF 3 O − closely resembles that of isoelectronic NF 3 O. For CF 3 O − , six fundamentals were observed and assigned consistent with a pseudo-tetrahedral structure of symmetry C 3 v . It is shown that the unusual bonding in NF 3 O is not unique but also occurs in CF 3 O − . In both isoelectronic X F 3 O species, the X O bond possesses almost double bond character whereas the three X F bonds are highly polar implying very strong contributions from resonance structures such as The occurrence of this type of bonding can be rationalized by the high electronegativity of fluorine and by the importance of the octet rule for first row elements limiting the sum of the bond orders to a maximum of four.

Vibrational spectrum and normal coordinate analysis of SF5Br

Abstract The i.r. spectrum of gaseous and the Raman spectrum of liquid SF5Br are reported. Ten out of 11 fundamentals expected for symmetry C4υ were observed and assigned. A normal coordinate analysis was carried out and thermodynamic properties in the range 0–2000 K were computed.

Substitution and addition reactions of NF4BF4 with aromatic compounds

Abstract Benzene, toluene, and nitrobenzene interact rapidly with NF 4 BF 4 in anhydrous HF to give, almost exclusively, fluorine substituted aromatic derivatives. Up to four hydrogens can be replaced in a rapid reaction, before a much slower addition reaction takes over. The direction of the substitution in C 6 H 6 , C 6 H 5 CH 3 and C 6 H 5 NO 2 and the lack of side chain fluorination in C 6 H 5 CH 3 support an electrophillic substituion mechanism. These rapid substitution reactions are followed by much slower fluorine addition reactions to give the corresponding cyclo-hexadienes and -hexenes. These addition reactions were also studied separately using tetra-, penta- and hexa- fluorobenzene as the starting materials. In these addition reactions, almost no hydrogen substitution occured. The addition of the first pair of fluorines always gave 1,4-cyclohexadienes in which CF 2 group was adjacent to hydrogen on the ring. The addition of the second pair of fluorines resulted in the formation of cyclohexenes. These reactions occured in high yield and offer a controlled, high yield path to dienes. All products were characterized spectroscopically and by comparison to literature data.

Bis-pentafluorotelluriumoxide fluorocarbons

Abstract The reaction of xenon bis-pentafluorotelluriumoxide, Xe(OTeF5)2, with the haloolefins; CF2=CFCl, CF2=CCl2, and CF2=CFH, results in the high yield addition of two TeF5O-groups to the double bond. These compounds are the first examples of Rf(OTeF5)2 compounds in which Rf is not perfluorinated. For perfluorobutadiene, saturation of both double bonds occurs readily to give 1,2,3,4(TeF5O)4C4F6 in 97% yield.

Synthesis of bis-pentafluorotelluriumoxide fluorocarbons

Abstract Xenon bis-pentafluorotelluriumoxide, Xe(OTeF 5 ) 2 , reacts with fluoroolefins to form fluorocarbons containing two TeF 5 O substituents. Olefins studied include tetrafluoroethylene, perfluoropropylene, and perfluorocyclopentene. Yields of these adducts are high (71–82%). Details of the synthesis and characterization of these new fluorocarbons are presented.

Vibrational spectra of thionyl tetrafluoride, SF4O

Abstract The i.r. spectra of gaseous, solid, and matrix-isolated SF 4 O and the Raman spectra of gaseous, liquid and solid SF 4 O are reported. It is shown that several bands previously attributed to SF 4 O belong to impurities, and 8 of the 12 fundamentals of SF 4 O were reassigned. A normal coordinate analysis was carried out and indicates for SF 4 O a structural model with significantly longer axial than equatorial SF bonds, in disagreement with Gundersen and Hedbergs favored Model A . Thermodynamic properties are also reported for SF 4 O.

Titanium tetraperchlorate and chromyl perchlorate

Abstract Syntheses of titanium tetraperchlorate and chromyl perchlorate are reported using chlorine perchlorate and the respective metal chlorides. These anhydrous metal perchlorates were found to contain bidentate perchlorato ligands.

Infrared spectrum of ClOSO2F

Abstract The infrared spectra of gaseous and solid ClOSO 2 F have been measured. Ten of the 12 fundamentals were observed and a vibrational assignment for symmetry C 3 is suggested. Some thermodynamic properties and principal force constants have been computed.