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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).

The structure of the very strong solid Lewis acid aluminum chlorofluoride (ACF, AlCl(x)F(3-x), x = 0.05-0.3) was studied by IR, ESR, Cl K XANES, (19)F MAS NMR, and (27)Al SATRAS NMR spectroscopic methods and compared with amorphous aluminum fluoride conventionally prepared by dehydration of alpha-AlF(3) x 3H(2)O. The thermal behavior of both compounds was investigated by DTA and XRD. In comparison to ACF, amorphous AlF(3) prepared in a conventional way is not catalytically active for the isomerization reaction of 1,2-dibromohexafluoropropane, which requires a very strong Lewis acid. Both compounds are mainly built up of corner-sharing AlF(6) octahedra forming a random network. The degree of disorder in ACF is higher than in amorphous AlF(3). Terminal fluorine atoms were detected in ACF by (19)F NMR. The chlorine in ACF does not exist as a separate, crystalline AlCl(3) phase. Additionally, chlorine-containing radicals, remaining from the synthesis, are trapped in cavities of ACF. These radicals are stable at room temperature but do not take part in the catalytic reaction.

The highly chlorinated, thermally stable [60]fullerene C 60 Cl 30 contains a cylinder-shaped carbon cage consisting of two aromatic six-membered rings and one equatorial 18p-trannulene belt separated by two 15-membered belts of sp 3 carbon atoms bearing Cl substituents. Find out more about the synthesis and properties of C 60 [1] To date, considerable success has been achieved in preparation and structural characterization of fullerene bromides [2] and fluorides.[3] Despite numerous reports on chlorination of C 60 by different reagents, [4] only two individual compounds have been isolated so far. The structure of C 60 Cl 6 formed in the reaction of ICl with C 60 in benzene was deduced from the 13 C NMR and IR spectra.[4b] C 60 Cl 24 was synthesized using VCl 4 and SbCl 5 ; a tetrahedral structure similar to that of C 60 Br 24 [2a, d] was assigned to this chloride on the basis of a comparison between the experimental and theoretically calculated IR spectra.[5]Here we report the synthesis and structural characterization of the novel, highly chlorinated fullerene C 60 Cl 30 . This chlorofullerene can be prepared using chlorinating agents such as ICl, ICl 3 , and SbCl 5 . Typically, 50-100 mg of C 60 and a large excess (~2 g) of chlorinating agents were sealed in glass ampules and heated at 220-250 8C for one to three days. Then, the ampules were opened, and the excess of the chlorinating agents and their decomposition products were removed in vacuo at 150 8C. Pure C 60 Cl 30 (1) was formed in the reaction of C 60 with SbCl 5 , whereas chlorination by ICl yielded the C 60 Cl 30 ·2 ICl solvate (2), both as dark-orange crystals stable in air. The IR spectrum of C 60 Cl 30 is presented in Figure 1. The most prominent bands are observed at ñ = 439, 450, 471, 479, 730, 775, 822, 854, 895, 903, 918, 958, 993, and 1447 cm À1 .[6]C 60 Cl 30 is insoluble in most common organic solvents such as diethyl ether, 1,4-dioxane, CH 2 Cl 2 , CHCl 3 , and CCl 4 ; it is poorly soluble in CS 2 , toluene, and chlorobenzene; and its solubility in 1,2-dichlobenzene was estimated at roughly 0.2 mg mL À1 . The thermal stability of C 60 Cl 30 appears to be remarkably high: its decomposes into C 60 and Cl 2 at 450-500 8C (Figure 2), which is about 120 8C higher than the temperature ranges previously reported for C 60 Cl 24 .[4b, 5] The mass loss for C 60 Cl 30 , 60.1 %, corresponds well to the calculated value of 59.75 %.

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Amorphous materials-magnesium oxide fluoride with hydroxy groups-of high surface area were prepared for the first time by a soft sol-gel method involving initial fluorination and subsequent hydrolysis of the fluorinated gel. Their structural properties were studied with XRD, FTIR, XPS, and 19 F MAS NMR. The magnesium oxide fluorides with hydroxy groups were also tested as heterogeneous catalysts in Michael additions. The incorporation of F into the MgO network led to diverse fluorine coordinations and high surface areas. The introduction of F into the framework enables a tuning of the base properties of the materials and leads to varied catalytic activities and selectivities. A weaker basicity can be obtained by the bridging of isolated OH groups in the MgF 2 network with increasing fluorine content. The sample prepared with an F : Mg molar ratio of 1.6 exhibited a catalytic activity similar to that of calcined Mg-Al hydrotalcites and selectively produced Michael addition products in high yields.