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The very strong Lewis acid aluminium chlorofluoride (ACF) was loaded with anhydrous HF. The interaction between the surface of the catalyst and HF was investigated using a variety of characterization methods, which revealed the formation of polyfluorides. Moreover, the reactivity of the HF-loaded ACF towards the hydrofluorination of alkynes was studied., (© 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

High-temperature trifluoromethylation of isolated-pentagon-rule (IPR) fullerene C 92 chlorination products followed by HPLC separation of C 92 (CF 3 ) n derivatives resulted in the isolation and X-ray structural characterization of IPR C 92 (38)(CF 3 ) 18 and non-classical C 92 (NC)(CF 3 ) 22 . The formation of C 92 (38)(CF 3 ) 18 as the highest CF 3 derivative of the known isomer C 92 (38) can be expected. The formation of C 92 (NC)(CF 3 ) 22 was interpreted as chlorination-promoted cage transformation of C 92 (38) followed by trifluoromethylation of non-classical C 92 (NC) chloride. Noticeably, C 92 (NC)(CF 3 ) 22 shows the highest degree of trifluoromethylation among all known CF 3 derivatives of fullerenes. The addition patterns of C 92 (38)(CF 3 ) 18 and C 92 (NC)(CF 3 ) 22 are discussed and compared to the chlorination patterns of C 92 (38)Cl n compounds., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Fluorine-containing polyanionic compounds have attracted much attention in the last few years as potential positive electrode materials for rechargeable batteries. With their formula A a M b X c O 4 Y d (A=Li, Na…; M=Ti, V, Mn, Fe, Co, Ni…; X=P or S, and Y=F, OH, O), they offer a very rich chemistry and their electrochemical properties can be tuned by carefully choosing the different constituting elements. However, synthesis approaches that allow these materials to be obtained at low temperature are almost nonexistent. In this paper, the use of a nonaqueous fluorolytic sol-gel approach is reported to synthesize a tavorite-type LiFePO 4 F material and its electrochemical characterization was performed. The obtained material displays an electrochemical performance that positively compares with the literature with an excellent cycling stability (115 mA h -1  g -1 after 100 cycles at C/2 rate). A slight change in the synthesis parameters allowed Li 2 CoPO 4 F to be successfully obtained, demonstrating the versatility of the reported route, which can be adapted to synthesize other fluorine-containing polyanionic compounds, which are of great interest for energy storage applications., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Anhydrous nanoscopic CuF 2 is synthesized from alkoxides Cu(OR) 2 (R=Me, tBu) by their reaction either in pure liquid HF at -70 °C, or under solvothermal conditions at 150 °C using excess HF and THF as solvent. Depending on the synthesis method, nanoparticles of sizes between 10 and 100 nm are obtained. The compound is highly hygroscopic and forms different hydrolysis products under moist air, namely CuF 2 ⋅2 H 2 O, Cu 2 (OH)F 3 , and Cu(OH)F, of which only the latter is stable at room temperature. CuF 2 exhibits an electrochemical plateau at a potential of ≈2.7 V when cycled versus Li in half cell Li-ion batteries, which is attributed to a non-reversible conversion mechanism. The cell capacity in the first cycle depends on the particle size, being 468 mAh g -1 for ≈8 nm crystallite diameter, and 353 mAh g -1 for ≈12 nm crystallite diameter, referred to CuF 2 . However, such a high capacity cannot be sustained for several cycles and the capacity rapidly fades out. The cell voltage decreases to ≈2.0 V for CuF 2 ⋅2 H 2 O, Cu 2 (OH)F 3 , and Cu(OH)F. As all the compounds studied in this work show irreversible conversion reactions, it can be concluded that copper-based fluorides are unsuitable for Li-ion battery applications., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Functionalization reactions of the refrigerants HFO-1234yf (2,3,3,3-tetrafluoropropene) and HFO-1234ze (1,3,3,3-tetrafluoropropene) were developed. The selectivity and reactivity towards CF 3 groups of C-F activation reactions can be controlled by employing either a germane or a silane as the hydrogen source. Unique transformations were designed to accomplish consecutive hydrogermylation and C-F activation steps. This allowed for an unprecedented transformation of an olefinic C-F bond into a C-H bond by heterogeneous catalysis. These reactions are catalyzed by nanoscopic aluminum chlorofluoride (ACF) under very mild conditions., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of novel highly soluble double-caged [60]fullerene derivatives were prepared by means of lithium-salt-assisted [2+3] cycloaddition. The bispheric molecules feature rigid linking of the fullerene spheres through a four-membered cycle and a pyrrolizidine bridge with an ester function CO 2 R (R=n-decyl, n-octadecyl, benzyl, and n-butyl; compounds 1 a-d, respectively), as demonstrated by NMR spectroscopy and X-ray diffraction. Cyclic voltammetry studies revealed three closely overlapping pairs of reversible peaks owing to consecutive one-electron reductions of fullerene cages, as well as an irreversible oxidation peak attributed to abstraction of an electron from the nitrogen lone-electron pair. Owing to charge delocalization over both carbon cages, compounds 1 a-d are characterized by upshifted energies of frontier molecular orbitals, a narrowed bandgap, and reduced electron-transfer reorganization energy relative to pristine C 60 . Neat thin films of the n-decyl compound 1 a demonstrated electron mobility of (1.3±0.4)×10 -3  cm 2  V -1  s -1 , which was comparable to phenyl-C 61 -butyric acid methyl ester (PCBM) and thus potentially advantageous for organic solar cells (OSC). Application of 1 in OSC allowed a twofold increase in the power conversion efficiencies of as-cast poly(3-hexylthiophene-2,5-diyl) (P3HT)/1 devices relative to the as-cast P3HT/PCBM ones. This is attributed to the good solubility of 1 and their enhanced charge-transport properties - both intramolecular, owing to tightly linked fullerene cages, and intermolecular, owing to the large number of close contacts between the neighboring double-caged molecules. Test P3HT/1 OSCs demonstrated power-conversion efficiencies up to 2.6 % (1 a). Surprisingly low optimal content of double-caged fullerene acceptor 1 in the photoactive layer (≈30 wt %) favored better light harvesting and carrier transport owing to the greater content of P3HT and its higher degree of crystallinity., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The chemistry of a giant fullerene, C 104 , has been extended by the synthesis and structural study of several chloro derivatives of three isolated pentagon rule (IPR) isomers of C 104 nos. 234, 812, and 811. In the structure of C 104 (234)Cl 16/18 , two molecules with 16 and 18 attached Cl atoms occupy the same crystallographic site with an occupancy ratio of 61/39. The structures of C 104 (812)Cl 12 and C 104 (812)Cl 24 demonstrate substructure relationships of their chlorination patterns with single and double Cl attachments to 12 cage pentagons. The structure of C 104 (811)Cl 28 is compared with the known C 104 (811)Cl 24 thus revealing dramatic changes in the chlorination pattern, which occur with relatively small increases in the degree of chlorination., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The homofullerene compound cis-2-C 60 (CF 2 ) 2 , which has an unusual kind of open/closed valence tautomerism undergoes consecutive regioselective hydrogenation at bridgehead carbon atoms upon reduction with Zn/Cu couple in H 2 O-toluene mixture. The tautomerism barrier in cis-2-C 60 (CF 2 ) 2 is negligible in the neutral state, whereas negative charging both impedes tautomeric transformation and promotes regioselective addition of electrophilic species at the bridgehead carbon atoms. In light of this observation, two novel homofullerene derivatives, mixed [6,6]-open/closed C 60 (CF 2 ) 2 H 2 and [6,6]-open cis-2-C 60 (CF 2 ) 2 H 4 , were synthesized and their structures were unambiguously determined by means of single crystal X-ray crystallography and NMR spectroscopy., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

CF3 -derivatized fullerenes prove once again to be promising scaffolds for regioselective fullerene functionalization: now with the smallest possible addends-hydrogen atoms. Hydrogenation of Cs -C70 (CF3 )8 and C1 -C70 (CF3 )10 by means of reduction with Zn/Cu couple in the presence of water proceeds regioselectively, yielding only one major isomer of C70 (CF3 )8 H2 and only two for C70 (CF3 )10 H2 , whose addition patterns are combined in the only abundant isomer of C70 (CF3 )10 H4 . The observed selectivity is governed by the electronic structure of trifluoromethylated substrates. Interestingly, we discovered that Clar's theory can be utilized to predict the regiochemistry of functionalization, and we look forward to testing it on forthcoming cases of derivatization of pre-functionalized fullerene building blocks., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High-temperature chlorination of pristine C98 fullerene isomers separated by HPLC from the fullerene soot afforded crystals of C98Cl22 and C98Cl20. An X-ray structure elucidation revealed, respectively, the presence of carbon cages of the most stable C2-C98(248) and rather unstable C1-C98(116), which represent the first isolated pentagon rule (IPR) isomers of fullerene C98 confirmed experimentally. The chlorination patterns of the chlorides are discussed in terms of the formation of isolated C=C bonds and aromatic substructures on the fullerene cages., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High-temperature chlorination of C100 fullerene followed by X-ray structure determination of the chloro derivatives enabled the identification of three isomers of C100 from the fullerene soot, specifically numbers 18, 425, and 417, which obey the isolated pentagon rule (IPR). Among them, isomers C1-C100 (425) and C2-C100 (18) afforded C1-C100 (425)Cl22 and C2-C100 (18)Cl28/30 compounds, respectively, which retain their IPR cage connectivities. In contrast, isomer C2v -C100 (417) gives Cs -C100 (417)Cl28 which undergoes a skeletal transformation by the loss of a C2  fragment, resulting in the formation of a nonclassical (NC) C1-C98 (NC)Cl26 with a heptagon in the carbon cage. Most probably, two nonclassical C1-C100 (NC)Cl18/22 chloro derivatives originate from the IPR isomer C1-C100 (382), although both C1-C100 (344) and even nonclassical C1-C100 (NC) can be also considered as the starting isomers., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High-temperature chlorination of three IPR isomers of fullerene C88 , C2 -C88 (7), Cs -C88 (17), and C2 -C88 (33), resulted in the isolation and X-ray structural characterization of C88 (7)Cl12 , C88 (7)Cl24 , C88 (17)Cl22 , and C88 (33)Cl12/14 . Chlorination patterns of C88 (7) and C88 (33) isomers are unusual in that one or more pentagons remain free from chlorination while some other pentagons are occupied by two or three Cl atoms. The addition patterns of the isolated chlorides are discussed in terms of the distribution of twelve pentagons on the carbon cages and the formation of stabilizing isolated C=C bonds and benzenoid rings., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High-temperature chlorination of fullerene C88 (isomer 33) with VCl4 gives rise to skeletal transformations affording several nonclassical (NC) fullerene chlorides, C86 (NC1)Cl24/26 and C84 (NC2)Cl26 , with one and two heptagons, respectively, in the carbon cages. The branched skeletal transformation including C2 losses as well as a Stone-Wales rearrangement has been comprehensively characterized by the structure determination of two intermediates and three final chlorination products. Quantum-chemical calculations demonstrate that the average energy of the C-Cl bond is significantly increased in chlorides of nonclassical fullerenes with a large number of chlorinated sites of pentagon-pentagon adjacency., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A generic route for the selection of nanoparticle stabilizers via biocombinatorial means of phage display peptide screening is presented, providing magnesium fluoride nanoparticle synthesis as example. Selected sequence-specific MgF2 binders are evaluated for their adsorption behavior. Peptide-polymer conjugates derived from the best binding peptide are used for the stabilization of MgF2 sol nanoparticles, yielding fully redispersable dry states and improoving processability significantly., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High-temperature chlorination of a fullerene C86 with VCl4 afforded non-classical C84Cl30 and C82Cl30 containing one and two heptagons, respectively, in the carbon cages. Two types of C2 losses, which differ in the final arrangements of separate or fused pentagons, can occur successively in either order, producing rather flat or concave regions on the shrinked carbon cage. In the chlorination-promoted skeletal transformation of C86 (isomer no. 16) with the loss(es) of C2 units, the structures of the starting, intermediate, and final compounds were all revealed unambiguously by X-ray single crystal diffraction., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chlorination of various HPLC fractions of C96 with a mixture of VCl4 and SbCl5 at 340-360 °C and single-crystal X-ray diffraction study of the products led to the identification of three new IPR isomers of C96. The C96(175) isomer forms a stable chloride, C96(175)Cl20, while chlorides of two other new isomers, C96(114) and C96(80), undergo cage shrinkage yielding C94(NC1)Cl28 and C96(NC2)Cl32 with non-classical (NC) cages. These two NC chlorides contain, respectively, one and two heptagons flanked by pairs of fused pentagons and are stabilized by chlorine attachment to the emerging pentagon-pentagon junctions. Thus, the number of the experimentally confirmed C96 isomers has reached nine, which corroborates the empirical rule that the C(6n) fullerenes exhibit particularly rich isomerism., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chlorination of C100 fullerene with a mixture of VCl4 and SbCl5 afforded C96Cl20 with a strongly unconventional structure. In contrast to the classical fullerenes containing only hexagonal and pentagonal rings, the C96 cage contains three heptagonal rings and, therefore, should be classified as a fullerene with a nonclassical cage (NCC). There are several types of pentagon fusions in the C96 cage including pentagon pairs and pentagon triples. The three-step pathway from isolated-pentagon-rule (IPR) C100 to C96(NCC-3hp) includes two C2 losses, which create two cage heptagons, and one Stone-Wales rotation under formation of the third heptagon. Structural reconstruction established C100 isomer no. 18 from 450 topologically possible IPR isomers as the starting C100 fullerene. Until now, no pristine C100 isomers have been confirmed based on the experimental results., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Isolation and characterization of very large fullerenes is hampered by a drastic decrease of their content in fullerene soot with increasing fullerene size and a simultaneous increase of the number of possible IPR (Isolated Pentagon Rule) isomers. In the present work, fractions containing mixtures of C102 and C104 were isolated in very small quantities (several dozens of micrograms) by multi-step recycling HPLC from an arc-discharge fullerene soot. Two such fractions were used for chlorination with a VCl4/SbCl5 mixture in glass ampoules at 350-360 °C. The resulting chlorides were investigated by single-crystal X-ray diffraction using synchrotron radiation. By this means, two IPR isomers of C104 , numbers 258 and 812 (of 823 topologically possible isomers), have been confirmed for the first time as chlorides, C1 -C104(258)Cl16 and D2-C104 (812)Cl24, respectively, while an admixture of C2 -C104(811)Cl24 was assumed to be present in the latter chloride. DFT calculations showed that pristine C104(812) belongs to rather stable C104 cages, whereas C104(258) is much less stable., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Trifluoromethylation of a higher fullerene mixture with CF3I was performed in ampoules at 550 °C. HPLC separation followed by crystal growth and X-ray diffraction study resulted in the structure elucidation of nine CF3 derivatives of D2d-C84 (isomer 23). The molecular structures of C84(23)(CF3)4, C84(23)(CF3)8, C84(23)(CF3)10, C84(23)(CF3)12, two isomers of C84(23)(CF3)14, two isomers of C84(23)(CF3)16, and C84(23)(CF3)18 were discussed in terms of their addition patterns and the relative formation energies. Extensive theoretical DFT calculations were performed to identify the most stable molecular structures. It was found that the addition of CF3 groups to the C84(23) fullerene is governed by two main rules: no additions in positions of triple hexagon junctions and predominantly para additions in C6(CF3)2 hexagons on the fullerene cage. The only exception with an isolated CF3 group in C84(23)(CF3)12 is discussed in more detail., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Trifluoromethylation of higher fullerene mixtures with CF(3)I was performed in ampoules at 400 to 420 and 550 to 560 °C. HPLC separation followed by crystal growth and X-ray diffraction studies allowed the structure elucidation of nine CF(3) derivatives of D(2)-C(84) (isomer 22). Molecular structures of two isomers of C(84)(22)(CF(3))(12), two isomers of C(84)(22)(CF(3))(14), four isomers of C(84)(22)(CF(3))(16), and one isomer of C(84)(22)(CF(3))(20) were discussed in terms of their addition patterns and relative formation energies. DFT calculations were also used to predict the most stable molecular structures of lower CF(3) derivatives, C(84)(22)(CF(3))(2-10). It was found that the addition of CF(3) groups to C(84)(22) is governed by two rules: additions can only occur at para positions of C(6)(CF(3))(2) hexagons and no additions can occur at triple-hexagon-junction positions on the fullerene cage., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

TIN, TAILORED, NOT SOLDER, BUT CAT: Doped hydroxylated fluorides, prepared by a modified sol-gel method, offer enhanced acidity and improved stability against water, and efficiency in the degradation of cellulose. These materials extend the portfolio of acid catalysts for fast and selective hydrolysis of biomass to glucose, which offers a feedstock for bioethanol production., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Minor isomer comes forward: Minor isomer C(84)(5) has been captured by high temperature trifluoromethylation with CF(3)I and chlorination with VCl(4). The compounds C(84)(CF(3))(16), C(84)Cl(20), and C(84)(5)Cl(32) were investigated by X-ray crystallography providing the first direct proof of the cage connectivity of D(2)-C(84)(5). The D(2)-C(84)(5)Cl(32) molecule (see figure; C grey, Cl green) contains two flattened, pyrene-like substructures on opposite poles of the cage resulting in its drum-like shape., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nanoscopic amorphous Lewis acidic aluminium fluorides, such as aluminium chlorofluoride (ACF) and high-surface aluminium fluoride (HS-AlF(3)), are capable of activating C-H bonds of aliphatic hydrocarbons. H/D exchange reactions are catalysed under mild conditions (40 °C)., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Three C(90) fractions were isolated by multi-step HPLC from fullerene soot obtained from direct current (DC) arc discharge of undoped graphite rods. C(90) of each fraction was chlorinated with VCl(4) or SbCl(5) in ampoules at 290-310 °C, affording a series of C(90)Cl(n) compounds. Single-crystal X-ray crystallography with the use of synchrotron radiation resulted in structure elucidation of seven C(90)Cl(n) compounds containing six different isolated pentagon rule (IPR) C(90) cages (the number of the C(90) isomer is given in the parentheses): C(90)(46)Cl(32) (I), C(90)(34)Cl(32) (II), C(90)(35)Cl(24) (III), and C(90)(35)Cl(28) (IV), C(90)(32)Cl(24) (V as co-crystals with III), co-crystals of C(90)(30)Cl(22) and C(90)(28)Cl(24) (VI), and C(90)(28)Cl(24) (VII). Cage connectivities of C(90) isomers 35 and 28 have been crystallographically confirmed for the first time. The chlorination patterns of the C(90)Cl(n) molecules are discussed in terms of the formation of isolated aromatic systems and isolated C=C double bonds on the fullerene cage. The distribution of six C(90) isomers in three HPLC fractions is compared with data from the literature.

Sc(3)N@C(80) (I(h)) was trifluoromethylated with CF(3)I at 400 °C affording a mixture of CF(3) derivatives. Two isomers of Sc(3)N@C(80)(CF(3))(14) and Sc(3)N@C(80)(CF(3))(16) were separated by HPLC and investigated by X-ray crystallography. Detailed comparison of the four isomers revealed a strong influence of the exohedral CF(3) addition pattern on the behavior of the Sc(3)N cluster inside the C(80) fullerene cage., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Perfluoroalkylation of a higher fullerene mixture with CF(3)I or C(2)F(5)I, followed by HPLC separation of CF(3) and C(2)F(5) derivatives, resulted in the isolation of several C(84)(R(F))(n) (n=12, 16) compounds. Single-crystal X-ray crystallography with the use of synchrotron radiation allowed structure elucidation of eight C(84)(R(F))(n) compounds containing six different C(84) cages (the number of the C(84) isomer is given in parentheses): C(84) (23)(C(2)F(5))(12) (I), C(84) (22)(CF(3))(16) (II), C(84) (22)(C(2)F(5))(12) (III), C(84) (11)(C(2)F(5))(12) (IV), C(84) (16)(C(2)F(5))(12) (V), C(84) (4)(CF(3))(12) (VI with toluene and VII with hexane as solvate molecules), and C(84) (18)(C(2)F(5))(12) (VIII). Whereas some connectivity patterns of C(84) isomers (22, 23, 11) had previously been unambiguously confirmed by different methods, derivatives of C(84) isomers numbers 4, 16, and 18 have been investigated crystallographically for the first time, thus providing direct proof of the connectivity patterns of rare C(84) isomers. General aspects of the addition of R(F) groups to C(84) cages are discussed in terms of the preferred positions in the pentagons under the formation of chains, pairs, and isolated R(F) groups.

Two for the price of one: The first halogenated derivative of C(90), C(90)Cl(32) (see structure; gray C, green Cl), is obtained by chlorination of a higher fullerene mixture with SbCl(5). Its molecular structure, elucidated by single-crystal X-ray diffraction, reveals the presence of two isomeric C(90) cages that correspond to C(2v) isomer 46 and C(s) isomer 34. The addition of 32 chlorine atoms is the maximum degree of chlorination achieved for fullerenes.

A non-aqueous sol-gel Al-based fluoride has been subjected to the microwave solvothermal process. The final material depends on the temperature heat treatment used. Three types of material have been prepared: 1) for low temperature heat treatment (90 degrees C) X-ray amorphous alkoxy fluoride was obtained; 2) for the highest temperature used (200 degrees C) the metastable form beta-AlF3 was obtained with a very large surface area of 125 m2 g(-1). The mechanism of the amorphous=crystalline transformation has been rationalised by the occurrence of a decomposition reaction of the gel fluoride induced by the microwave irradiation. 3) Finally, at intermediate temperature (180 degrees C) a multi-component material mixture exhibiting a huge surface area of 525 m2 g(-1) has been obtained and further investigated after mild post-treatment fluorination using F2 gas. The resulting aluminium-based fluoride still possesses a high-surface-area of 330 m2 g(-1). HRTEM revealed that the solid is built from large particles (50 nm) identified as alpha-AlF3, and small ones (10 nm), relative to an unidentified phase. This new high-surface-area material exhibits strong Lewis acidity as revealed by pyridine adsorption and catalytic tests. By comparison with other materials, it has been shown that whatever the composition/structure of the Al-based fluoride materials, the number of strong Lewis acid sites is related to the surface area, highlighting the role of surface reconstruction occurring on a nanoscopic scale on the formation of the strongest Lewis acid sites.

Novel magnesium fluorides have been prepared by a new fluorolytic sol-gel synthesis for fluoride materials based on aqueous HF. By changing the amount of water at constant stoichiometric amount of HF, it is possible to tune the surface acidity of the resulting partly hydroxylated magnesium fluorides. These materials possess medium-strength Lewis acid sites and, by increasing the amount of water, Brønsted acid sites as well. Magnesium hydroxyl groups normally have a basic nature and only with this new synthetic route is it possible to create Brønsted acidic magnesium hydroxyl groups. XRD, MAS NMR, TEM, thermal analysis, and elemental analysis have been applied to study the structure, composition, and thermal behaviour of the bulk materials. XPS measurements, FTIR with probe molecules, and the determination of N(2)/Ar adsorption-desorption isotherms have been carried out to investigate the surface properties. Furthermore, activity data have indicated that the tuning of the acidic properties makes these materials versatile catalysts for different classes of reactions, such as the synthesis of (all-rac)-[alpha]-tocopherol through the condensation of 2,3,6-trimethylhydroquinone (TMHQ) with isophytol (IP).

Deflated buckyballs: The single-crystal structure of C 60 F 48 ⋅2 (mesitylene) revealed the presence of both D 3 and S 6 isomers in the same crystal. C(sp 2 )-C(sp 2 ) bonds (1.30 Å) are much shorter than C(sp 3 )-C(sp 3 ) bonds (1.54-1.63 Å). The C 60 cage is characterized by concave areas in the regions of six double bonds. Each double bond is effectively shielded by four F atoms, which accounts for the low reactivity of C 60 F 48 ., (© 2001 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.)