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The syntheses of homoleptic metal carbonyl cations [M(CO)6](super 2+) (M=Fe, Ru, Os) as [BF4](super -) salts in a bronsted lewis superacid, HF/BF(super 3) by oxidative carbonylation of Fe(CO)5 and M3(CO)12 (M=Ru, Os) is reported. The salts exhibit unexpected thermal stabilities and the compounds [M(CO)6][BF4]2 (M=Fe, Os) are characterized by single-crystal X-ray diffraction, and the Ru and Os salts are characterized by powder diffraction.

Homoleptic octahedral, superelectrophilic sigma-bonded metal carbonyl cations of the type [M(CO)6](super 2+) (M=Ru, Os) are generated in the Bronsted-Lewis conjugate superacid HF/SbF5 by reductive carbonylation of M(SO3F)3 (M=Ru, Os) or OsF6. Observations state that the octahedral [M(CO)6](super 2+) cations (M=Fe, Ru, Os) should also be generated in other Bronsted-Lewis superacids and stabilized by counteranions other than the fluoroantimonates.

Solutions of Sb[F.sub.5] in HS[O.sub.3]F with [x.sub.[SbF.sub.5]] = 0.012 to 0.405 are studied by 500 MHz [sup.1]H NMR (299 K) and 471 MHz [sup.19]F NMR (213-250 K), using NMR tubes fitted with fluoropolymer lining. The initial process during dissolution is the fast solvolysis of monomeric Sb[F.sub.5] in HS[O.sub.3]F according to Sb[F.sub.5] + nHS[O.sub.3]F [right arrow] + Sb[F.sub.5-n] [(S[O.sub.3]F).sub.n] + nHF (n = 1, 2). All HF formed during solvolysis will no longer be removed by reaction with glass, but will remain in the superacid system. Besides participation in the fast formation of various fluoro-fluorosulfato anions [[Sb[F.sub.6 - n] [(S[O.sub.3]F).sub.n]].sup.-] (n = 0, 1, 2) and acidium ions [[H.sub.2]X].sup.+.sub.(solv.)] (X = F, S[O.sub.3]F), HF is involved in slow-exchange reactions of the type [[Sb[F.sub.6 - n][(S[O.sub.3]F).sub.n]].sup.-.sub.(solv.)] + HF [right arrow] [[Sb[F.sub.7 - n][(S[O.sub.3]F).sub.n - 1]].sup.-.sub.(solv.)] + HS[O.sub.3]F (n = 1, 2) detected because of a delay of 3 months between sample preparation and measurements and confirmed by repeating theses measurements after a further 3 months. There are three notable differences to our earlier study, affecting concentrations of the fluoro-fluorosulfato antimonate anions observed: (i) in dilute solutions [[Sb[F.sub.6]].sup.-] is formed in high concentrations (34.7 -76.1%), with [[S[b.sub.2][F.sub.11]].sup.-] now clearly detected at intermediate to high Sb[F.sub.5] concentrations (up to 5.8%); (ii) bis-fluorosulfato anions (cis-, trans-[[Sb[F.sub.4][(S[O.sub.3]F).sub.2].sup.-]) are found in much lower concentrations only, which decrease further with time, while tris-fluorosulfato anions ([[Sb[F.sub.3][(S[O.sub.3]F).sub.3]].sup.-]) are now no longer observed; (iii) these reduced concentrations of polyfluorosulfato anions in dilute solutions are responsible for the formation of fewer [micro]-S[O.sub.3]F-oligomers at lower concentrations, when more Sb[F.sub.5] is added. As a consequence, the HS[O.sub.3]F-Sb[F.sub.5] magic acid system is now less complex than found previously and only seven anionic species are clearly observed. Key words: superacids, antimony(V) fluoroanions, [sup.1]H NMR, [sup.19]F NMR, solvolysis.

A study of square planar palladium(II) and platinum(II) carbonyl derivatives, the molecular structure of cis-Pt(CO)(sub 2)(SO3F)(sub 2), the complete vibrational spectra of cis-Pt(CO)(sub 2)Cl2, and the attempted synthesis of cis-Pt(CO)(sub 2)F2 is presented. The results show the reductive carbonylation of PtF6 in HF produces with [Pt(CO)(Sub 4)][PtF6] the first carbonyl fluoride of platinum, and the reaction of [Pt(CO)(sub 4)][Sb2F11](sub 2) and CsF in HF results in the formation of an anionic cluster complex Cs2[Pt3(CO)(sub 6)](sub n=10).

Research has been conducted on the bis(mu-chloro)tetracarbonyldirhodium(I) and chlorotricarbonyliridium(I). The reactions of these compounds in conjugate Bronsted-Lewis superacid and in CO atmosphere are described.

Research was conducted to extend the existence range of the predominantly sigma-bonded homoleptic metal carbonyl cations(super 2,3) and their derivatives to molybdenum, a group 6 metal. The use of superacid media in synthesis and product isolation made it possible to include the first cationic derivative formed by an early transition metal with a d4 configuration. This is the first known synthetic method that yields any thermally stable, homoleptic metal carbonyl cations and their derivatives with metals in +2 or +3 oxidation states.

Six superacid anions are examined for their structural and bonding features to find explanation for their low nucleophilicity and their ability to engage in secondary interionic contacts with electrophilic cations. These anions are SO3F- and (H(SO3F)2)-, derived from the Bronsted superacid HSO3F, and (Au(SO3F)4)-, (Pt(SO3F)6)(super 2-) and (Sb(SO3F)6) from conjugate superacids in HSO3F. (H3O)(Sb2F11), formed from magic acid HSO3FSbF5 was also studied.

The carbon monoxide addition to iridium(III) fluorosulfate and subsequent evaporation resulted to the crystal formation of mer-Ir(CO)3(SO3F)3. Its molecular structure has an octahedral coordination about the iridium atom with a meridional stereochemistry. The extramolecular C-O interaction molecule connections resulted to an extended three-dimensional structure. The molecular structure also showed significantly reduced pi-back donation. Vibrational spectra of the crystal recorded extensive band splitting in the 1000-800 cm region.

Heating of the isomeric mixture of Pd(CO)2(SO3F)2 in HSO3F at 60 degrees produces single crystals of cis-bis(carbonyl)palladium(II)fluorosulfate. X-ray analysis shows a square planar coordination of palladium with terminal CO groups. Higher CO-stretching frequencies and short CO bond lengths suggest decreased pi-back-donation. Secondary contacts of the carbon atom of the CO group provide charge compensation and structure stability.

Cyclo-bis(mu-carbonyl)dipalladium(I) fluorosulfate is experimentally investigated to determine the molecular structure and complete vibrational spectrum of the compound. The production of the compound involves the reductive decomposition of Pd(CO)2(SO3F)2 in fluorosulfuric acid at a temperature of 25 degrees centigrade. The compound is formed as long orange-red needles after a period of 3 weeks.

Oxidative carbonylation of Fe(CO)5 in liquid SbF5 and a CO atmosphere, with either AsF5 or Cl2 as extreme oxidizing agents, produced (Fe(Co)6)(Sb2F11)2 in very high yield. The resulting off-white solid material was thermally stable above 200 degrees C. The homoleptic carbonyl cation (Fe(CO)6)2+ was isostructural with (Ru(CO)6)2+ and (Os(CO)6)2+ which were obtained by reductive carbonylation of M(SO3F)3, M=Ru or Os. The stretching force constant indicated substantially reduced pi-back-bonding. The single line 57Fe Mossbauer spectrum was consistent with a regular octahedral structure and a 1A1g groundstate for (Fe(CO)6)2+.

The rotational spectra of the fluorosulfate (FSO3·) molecular radical in its vibronic ground state were measured in the millimeter-wave region and analyzed in detail using the matrix elements of the rotational, fine, and hyperfine Hamiltonian terms. The analysis of the assigned transition frequencies made it possible to derive very precise values of the rotational, centrifugal distortion and fine structure constants and to confirm the C3v molecular symmetry of the vibronic ground state unambiguously. In addition, an effective parameter of the “A1-A2 splitting” was determined. The rotational transitions of the FSO3· free radical were observed, identified, and analyzed for the first time. [ABSTRACT FROM AUTHOR]

Study presents a convenient one-step synthesis for [[Mn(CO6]sup.+]. This approach involves the one electron oxidation of Mn2(CO)10 by protons in solutions of Lewis acids (BF3, (CF3)3BC) and anhydrous HF.

Research has been conducted on dimeric rhodium(I) bis(carbonyl) chloride. The reaction of this compound with Lewis acids carried out in CO atmosphere at room temperature has led to salts which have been characterized by Raman spectroscopy and single-crystal X-ray diffraction.

Tris(trifluoromethyl)borane carbonyl, (CF3)(sub 3)BCO, is obtained in high yield by the solvolysis of K[B(CF3)(sub 4)] in concentrated sulfuric acid. Its molecular structure has been determined by a combination of electron diffraction and microwave spectroscopy in the gas phase and by single crystal X-ray diffraction.

The reaction of tungsten hexacarbonyl, W(CO)(sub 6), with antimony(V) fluoride, SbF5, in the conjugate Bronsted-Lewis superacid HF-SbF(sub 5) at 40 degree Celsius produces quantitatively the salt [W(CO)(sub 6)(FSbF(sub 5))][Sb(sub 2)F(sub 11)] as the main product. The observed 2e(super -) oxidation without any loss of CO is unprecedented. The molecular structure of this salt is compared to that of polymeric.

Crystalline cubes of cesium hexakis(fluorosulfato)antimonate(V) may be synthesized by reacting an equal proportion of CsSO3F and antimony with an excess of bis(fluorosulfuryl) peroxide in HSO3F. Oxygen atoms not linked to Sb are coordinated to Cs+, which has a coordination number of 12. The anion (Sb(SO3F)6)- has an S6 symmetry and may be a weak nucleophile. Because of the strong symmetry and the great strength of S-O and S-F pi-bonds in the fluorosulphate groups, it is expected that the conjugate superacid system HSO3F-Sb(SO3F)5 will be strongest of the series found to date.

A structural, synthetic, spectroscopic and computational investigation of [M(CO)4][Sb2F11]2, M = Pd, Pt, is presented. The square planar [M(CO)4]2+ cations are found to be a vital element of a series of thermally stable, superelectrophilic metal carbonyl cations.

A synthetic approach, in which the Lewis superacid SbF5 is substituted by the conjugate Bronsted-Lewis superacid HF-SbF5 as the reaction medium and the XeFe2 is used as the oxidizing agent in the oxidative carbonylation of Fe(CO)5, resulted in high yields of (Fe(CO)6)(Sb2F11)2 in the form of single crystals. The molecular structure of (Fe(CO)6)(Sb2F11)2 was determined by X-ray diffraction. The use of anhdrous hydrogen fluoride as a solvent facilitated the conversion of (Fe(CO)6)(Sb2F11)2 to (Fe(CO)6)(SbF6)2 as single crystals, allowing its molecular structure to be readily obtained. The stabilization of (Fe(CO)6)(super 2+) by the counterions (Sb2F11)- and (SbF6)- allowed for the normal coordinate analysis of the cation.