This study was initiated by the search for novel superacid systems based on HSO₃F, the strongest simple protonic acid. Therefore, the synthesis of binary metal fluorosulfates, M(SO₃F)n, was investigated, with special emphasis on compounds where M is in a medium or high oxidation state and formally coordinatively unsaturated, i.e., n = 3,4 or 5. Preferably, the resulting fluoro-sulfate would also display a sufficiently high thermal stability with respect to dissociations giving rise to SO₃ or S₂O₅F₂, and reasonable solubility in HSO₃F. In order to obtain suitable binary fluorosulfates, a new, generally applicable synthetic method was developed, involving the oxidation of a metal with S₂O₆F₂. In presence of HSO₃F: M+ n/2 S₂O₆F₂ -- HSO₃F M(SO₃F)[sub= n], where M is primarily a 4d or 5d transition metal, in particular, palladium, platinum, gold and iridium. This fluorosulfonation mixture combines the strong oxidizing ability of S₂O₆F₂ with the good solvating property of HSO₃F towards ionic solutes. The ability of these binary fluorosulfates to act as fluorosulfate ion acceptors was established by the synthesis of anionic complexes of the type [M(SO₃F)[sub= n+m][sup= m-], where m = 1,2. Both Au(SO₃F)₃ and Pt(SO₃F)₄ were found to act as ansolvo-acids in H SO₃F by the removal of fluorosulfate ions from the solvent ionization equilibrium: 2H SO₃F > H₂SO₃F⁺ + SO₃F⁻, to form [Au(SO₃F)₄]⁻ or [Pt(SO₃F)₆]²⁻ . Results from conductivity measurements indicate the resulting superacids have acid strengths comparable to that of the HSO₃F-SbF₅-SO₃ system and definitely superior to the HSO₃F –SbF₅ system. In both cases, the variety of ternary fluorosulfates synthesized included unusual cations such as Br₃⁺ and Br₅⁺. In the case of platinum, evidence for poly-nuclear oligomeric anions of the type of [Pt(SO₃F)₅][sub= n][sup= n-] were obtained; similar observations were also made in the tin system. The oxidation of palladium yielded Pd(SO₃F)₂ and a mixed valency compound, Pd(II)[Pd(IV)(SO₃F)₆], both containing Pd(II) in a rather uncommon octahedral coordination sphere and a ³A₂₉ electronic ground state. These magnetically dilute compounds allowed meaningful magnetic results and ligand field parameters to be interpreted. Both Ir(S0₃F)₃ and Ir(SO₃F)₃ could be synthesized, along with some tenary fluorosulfate complexes. Some preliminary results were also obtained on the fluorosulfates of germanium, molybdenum, niobium and tantalum. / Science, Faculty of / Chemistry, Department of / Graduate

A number of synthetic routes to silver(II) fluorosulfate, Ag(SO₃F)₂, were systematically explored. The most suitable and versatile route was found to be the oxidation of silver metal by a solution of bisfluorosulfuryl peroxide, S₂0₆F₂, in fluorosulfuric acid, HSO₃F, according to: [chemical reaction] Additional methods which were found to be suitable involved the oxidation of a wide variety of silver(I) compounds such as Ag₂0 or AgSO₃F by S₂O₆F₂' or the insertion of S0₃ into AgF₂. Structural conclusions on Ag(S0₃F)₂ and the other compounds synthesized subsequently were based on the vibrational, electronic and electron spin resonance spectra, as well as on magnetic susceptibility measurements made between 300 and 77 K. Ag(S0₃F) ₂was found to be a true compound of divalent silver, with the Ag²⁺ ions in either square planar or tetragonally elongated octahedral environment. The only other example of a binary silver(II) compound is AgF₂. and characterized. The reactions of bromine(I) fluorosulfate with metallic silver and other silver(I) substrates resulted in a mixed valence complex Ag[sup I]Ag[sup II](SO₃F)₄ . Its potassium analogue K₂AgCSO₃F)₄, as well as two hexakisfluorosulfato- metallate (IV) complexes AgPt[sup= IV] (SO₃F)₆ , and AgSn[sup= IV] (SO₃F)₆, and the N-donor ligand complex [Ag(bipy)₂l (SO₃F)₂ (i-n which bipy = 2,2'-bipyridine) were also synthesized. The attempt to synthesize a silver(III) fluorosulfato complex by direct insertion of SO₃ into CsAgF₄ resulted in the fluorination of SO₃, to give S₂O₆F₂ and CsAg(SO₃F)₃. Finally, the solvolysi of Ag(SO₃F)₂ in trifluoromethylsulfuric acid, HSO₃CF₃, allowed its conversion into Ag(SO₃F₃). The principal synthetic route, the oxidation of metal by S₂O₆F₂ solutions in HSO₃F, was found to be useful in the preparation of Ru(SO₃F)₃. Ruthenium was also found to form a number of anionic derivatives with the metal in the +3 or +4 oxidation state, as in M[Ru(SO₃F)₄] with M = Cs⁺, ClO₂⁺ ; M₂[Ru(SO₃F)₆ with M = Cs⁺, K⁺; and Cs[Ru(SO₃F)₅]. Two different forms of Os(SO₃F)₃ were found. Initial oxidation of osmium metal with S₂O₆F₂ yielded the bright green a-Os(SO₃F)₃, which was converted to the light green β-form on long standing in S₂O₆F₂. / Science, Faculty of / Chemistry, Department of / Graduate

<p> The cryoscopic constant for fluorosulphuric acid has been determined and the nature and concentration of the impurities in the solvent have been investigated.</p> <p> The NMR and Gouy methods have been used to determine the magnetic susceptibility of solutions of iodine fluorosulphates. The NMR method has been shown to lead to spurious results.</p> <p> Cryoscopy, conductivity and UV and visual spectrophotometry have been used to elucidate the state of iodine fluorosulphates in fluorosulphuric acid. Solutions of stoichiometry corresponding to fifth-, third-, half-, uni-, tri-, and hepta-valent iodine have been investigated. The highest valence state observed was that of iodine trifluorosulphate which has been shown to be an acid in fluorosulphuric acid. Measurements on fifth- and third-valent iodine solutions indicate that I5+ and I3+ are formed. Measurements on half- and univalent iodine solutions suggest that I2+ is formed. The observed magnetic moment of this species agrees well with that required by theory, 2.0 BM.</p> / Thesis / Doctor of Philosophy (PhD)