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This review article focuses on the mechanism of the non-aqueous fluorolytic sol gel-synthesis of nanoscopic metal fluorides and hydroxide fluorides. Based on MAS-NMR, XRD, WAXS and SAXS investigations in combination with computational calculations, it is shown that a stepwise replacement of alkoxide by F-ions takes place resulting in the formation of a large variety of metal alkoxide fluoride clusters, some of them being isolated and structurally characterised. It is shown that these nanoscopic metal fluorides obtained via this new synthesis approach exhibit distinctly different properties compared with their classically prepared homologues. Thus, extremely strong solid Lewis acids are available which give access to new catalytic reactions with sometimes unexpectedly high conversion degrees and selectivity. Even more interestingly, metal hydroxide fluorides can be obtained via this synthesis route that are not accessible via any other approach for which the hydroxide to fluoride ratios can be adjusted over a wide range. Optically fully transparent sols obtained in this way can be used for the first time to manufacture antireflective coatings, corundum ceramics with drastically improved properties as well as novel metal fluoride based organic–inorganic composites. The properties of these new fluoride based materials are presented and discussed in context with the above mentioned new fields of application.

Porous molecular nanocontainers of the {Mo132} Keplerate [{(MoVI)MoVI5O21 (H2O) 5F}12{MoV2O4(F) (H2O)}30]·≈250H2O (I) precipitates from an aqueous HF solution of [NH4]72 [{(Mo)Mo5O21 (H2O)6}12{Mo2O4 (CO3)}30]·≈260H2O (II) and Me2NH2F (air, 5 d, 66% yield).

Chlorination of the C100 (18) fullerene with a mixture of VCl4 and SbCl5 gives rise to branched skeletal transformations affording non-classical (NC) C94 (NC1)Cl22 with one heptagon in the carbon cage together with the previously reported C96 (NC3)Cl20 with three heptagons. The three-step pathway to C94 (NC1)Cl22 starts with two successive C2 losses of 5:6 CC bonds to give two cage heptagons, whereas the third C2 loss of the 5:5 CC bond from a pentalene fragment eliminates one of the heptagons. Quantum-chemical calculations demonstrate that the two unusual skeletal transformations-creation of a heptagon in C96 (NC3)Cl20 through a Stone-Wales rearrangement and the presently reported elimination of a heptagon through C2 loss-are both characterized by relatively low activation energy.

This perspective article focuses on nanoscopic metal fluorides and hydroxide fluorides prepared via a recently explored fluorolytic sol–gel synthesis approach. Metal fluoride phases obtained via this route exhibit distinctly different properties compared with their classically prepared homologues. Thus, extremely strong solid Lewis acids are available which give access to new catalytic reactions with sometimes unexpectedly high conversion degrees and selectivity. Even more interestingly, metal hydroxide fluorides can be obtained via this synthesis route, which are not accessible via any other approach for which the hydroxide to fluoride ratio can be adjusted over a wide range. As a result, bi-acidic (Bronsted and Lewis) solids with tunable Lewis to Bronsted acidity can be obtained which show interesting results in a variety of reactions. Finally, these new nano-metal fluorides, due to their very high surface areas and distinct acidic properties, can be used as supports for many novel metal catalysed reactions, thus showing surprising synergistic effects. This overview will briefly outline the synthesis approach of the fluorolytic sol–gel route, will present characteristic bulk and surface properties and will give several examples of their novel catalytic applications in purely Lewis acid and in bi-acidic catalysed reactions, and will also exemplarily show the potential of these new materials as supports for heterogeneous catalytic reactions.

Highly transparent ytterbium fluoride sols of high concentration and low viscosity are prepared by the fluorolytic sol—gel synthesis.

Nanocrystalline phase-pure metal fluorides MF2 (M: Ca, Sr, Ba) are obtained by simple mixing or shaking of alkaline earth hydroxides with NH4F.

synthesis, separation, and X-ray crystallographic analysis of C88(CF3)nderivatives (n = 16, 18, 20)

Nanocrystalline alkaline earth metal fluorides MF2 (M: Mg, Ca, Sr, Ba) are mechanochemically synthesized by high energy ball milling of mixtures of the metal sources (acetates, carbonates, hydroxides, alkoxides) and NH4F as fluorinating agent.

Abenquines A, B1, B2, C and D (Ia)—(Ie), resp., show inhibitory activity against bacteria, dermatophytic fungi and phosphodiesterase type 4b.

Fluorocyclohexa adducts C60(C4F8)n were synthesized by high-temperature reaction of fullerene C60 with 1,2-C2F4I2 or 1,4-C4F8I2 in sealed tubes. Their separation by HPLC allowed us to determine molecular structure (X-ray diffraction) of four new compounds C6(C4F8)n (n = 2, 3, 4, and 6). Structures of isomers C60(C4F8)n were discussed in terms of a concept of consecutive addition of C4F8 groups to the fullerene cage.

The title phases (x ≈ 1.5) with pyrochlore structure are mechanochemically synthesized for the first time using γ-Al(OH)3 and β-AlF3·3H2O with an Al:F ratio of 1:1.5.

Depolarized Rayleigh spectra of ortho‐terphenyl (OTP) were measured in the temperature range from Tg to Tg+190 K. Two samples prepared with and without ‘‘clusters’’ were used for the measurement. Four different Fabry–Perot interferometers covering the time range from about 0.5 ps to 100 ns were employed. Two relaxation modes were observed: a slow mode with all its characteristics of the α process, and a fast mode with a constant, temperature independent relaxation time of about 3 ps. The fast mode has not been reported heretofore. The intensity of the fast mode vanishes at about the Vogel–Fulcher–Tamman temperature T0. The relaxation times of these two processes are found to be identical for both OTP with and without clusters. The temperature dependence of the relaxation time of the α process is Arrhenius at high temperatures, but shows a Williams–Landel–Ferry (WLF) behavior in the range from Tg to Tg+80 K for both samples with and without the long‐range density fluctuations (i.e., cluster).

Three-component reactions with aldehydes, trimethylsilyl trifluoro- methanesulfonate or iodide. and triphenylphosphine (TPP) yield the title compounds. The X-ray structure of the cationic part of a representative product, the (4-methylphenyl)[(trimethylsiloxy) methyl]TPP + , shows an interesting lengthening of the P + -C(α) bond compared with reported values for methyl(TPP) + and benzyl(TPP) + cations (C(α) represents the P-bonded carbon atom of the various alkyl groups). The behavior of the title compounds towards charged nucleophilic reagents and a powerful electrophile (trifluoromethanesulfonic anhydride) is similar to that of analogous pyridinium salts

Temperature-programmed desorption of ammonia has been employed for the characterization of halogen exchange catalysts. Nonactivated and activated catalysts are compared in regard to their behavior in adsorption and desorption. Activation of γ-alumina and AlF 2 (OH) increases both the catalytic activity for halogen exchange and the amount and strength of ammonia adsorption. In constrast, β-AlF 3 possesses catalytic activity already without activation. This substance reveals no significant alteration of ammonia adsorption after activation. A connection was observed between the acidity of the catalysts and their reactivity. The nature of the acidic sites was determined by Fourier transform infrared photoacoustic spectroscopy of pyridine chemisorbed on the solid surfaces. The results indicate that Lewis acid sites of a certain strength are responsible for the catalytic activity.

New isomers of trifluoromethyl derivatives of [70]fullerene, C70(CF3)12 (one isomer), C70(CF3)14 (three isomers), and C70(CF3)16 (one isomer) were synthesized, chromatographically isolated, and characterized by single-crystal X-ray analysis. Three of the five new isomers were obtained by annealing a mixture of higher trifluoromethyl derivatives (realkylation*). Trifluoromethylation of two individual C70(CF3)12 isomers revealed rearrangements of CF3 groups on the fullerene sphere along with the direct addition to the double bonds. The relative energies of the isomers were calculated using the density functional theory.

A convenient synthesis of the potent human NK-3 receptor antagonist SR 142801, (S)-(+)-N-{{3-[1-benzoyl-3-(3,4-dichlorophenyl)piperidin-3-yl]prop-1-yl}-4-phenylpiperidin-4-yl}-N-methylacetamide [(S)-(+)-(15)], is described. Improvements over the previously reported procedure are the preparation of the intermediate 5 via the novel imide 3 and subsequent reaction with the nucleophile 14, which reacts, regioselectively, at the endocyclic nitrogen.

Various modified zirconium and titanium dioxides were examined as catalysts for the following test reactions: the gas phase alkylation of 1-butene with isobutane, the double bond isomerization of 1-butene and the disproportionation of dichlorodifluoromethane. The catalysts were prepared by treatment of the precipitated oxide hydrates with either fluorinating, chlorinating, sulfatizing or phosphating agents. The nature of the acid sites was determined by IR spectra of pyridine adsorption complexes and correlated with the catalytic behavior. An activation of zirconium dioxide with sulfur tetrafluoride led to the formation of a larger number of Bronsted acid sites than those obtained for sulfated zirconia. The isooctane yields during the alkylation offered a similar graduation. An enhancement of the number and strength of Lewis acid sites presupposed for the disproportionation test reaction was not observed. Samples based on titanium dioxide exhibited an overall lower catalytic activity. The reaction mechanism of the alkylation of 1-butene with isobutane was proposed.

An alternate enantiospecific synthesis of methyl (S)-7-tert-butoxycarbonyl-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate ( 5 ) is reported. The key step, which involves an intermolecular displacement of the activated aryl fluoride ( 9 ) by L-aspartic acid β-methyl ester, proceeds without racemization.