The synthesis of DPA-VPI-5 and TBA-VPI-5 and their phase transformation to AIPO4-8 have been studied by X-ray diffraction in situ. The synchrotron radiation-energy dispersive diffraction is shown to be able to monitor these two fast reactions in real time. The results indicate that nucleation may occur already during the aging of the synthesis gel. The different rates oftransformtion of DPA-VPI-5 and TBA-VPI-5 show that the microstructure of the two materials is different.

Solid-state 13C NMR spectra of graphite oxide GO. and its derivatives prompt us to propose a new structural model. The spectra of GO treated with KI and the course of the thermal decomposition of GO reveal the presence of epoxide groups, responsible for the oxidating nature of the material. GO is built of aromatic'islands' of variable size which have not been oxidized, and are separated from each other by aliphatic 6-membered rings containing C-OH, epoxide groups and double bonds. The carbon grid is nearly flat; a small degree of warping is caused by the carbons attached to OH groups, which are in a slightly distorted tetrahedral configuration.

Stable van der Waals-bonded C60/benzene solvates were prepared using a novel crystallization technique. Solid-state NMR measurements on highly crystalline solvate under liquid benzene show that there is very little interaction between benzene and the C60 molecules and that the rotation of C60 at room temperature is not hindered. The magnetization transfer between benzene protons and local C60 molecules is highly inefficient. Three benzene species have been found in the solvate: two, nearly freely mobile, in wide and narrow porous structures, and the third constrained by C60 molecules in lattice defects. Premelting of deuterated benzene within the C60 solvate has been observed at Tm-10.5 K.

ZEOLITES derive their catalytic activity from the strong acidity of protons attached to the negatively charged aluminosilicate frame-work, which makes the materials excellent proton donors. Unlike zeolites, the aluminophosphate molecular sieves1,2 are built from alternating AIO4 and PO tetrahedra and are thus electrically neutral. Much attention has therefore been devoted to the genera-tion of Br0nsted acidity in these materials by introducing het-eroatoms, such as Si, Mg, Fe, Co or Zn, to produce negatively charged frameworks3-6. Similar arguments apply to gallophos-phate molecular sieves7-10, of which cioverite9,to is a remarkable example. This extra-large-pore material contains pore openings in the form of a four-leafed clover, defined by a ring of 20 gallium and phosphorus atoms, some of which are linked to terminal hydroxyl groups. Here we use NMR, X-ray photoelectron spectroscopy (ESCA) and infrared spectroscopy to show that the P-OH groups in cloverite are localized versions of those in solid phosphoric acid, H3PO4. Cloverite is thus a strong Br0nsted acid even though no heteroatoms are present in its framework.

The effects of pore structure on the reaction rates and selectivities in the liquid-phase hydrogenation of 2-ethylanthraquinone over Ni-B amorphous alloy catalysts prepared by the reductant-impregnation method were studied using regular (HMS, MCM-41, and SBA-15) and commercial mesoporous silicas as supports. The composition, particle size, and location of the Ni-B particles were profoundly influenced by the pore structure of the supports. It is found that the location of the Ni-B particles depended on the pore size of the supports, whereas the uniformity of particle size was related to the interaction between the Ni-B particles and the supports. The hydrogenation rate was much faster on Ni-B catalysts with pore diameters exceeding 5 nm than on the narrow-pore catalysts, whereas the selectivity to 2-ethyldihydroanthraquinone, the carbonyl group hydrogenation product, was higher on Ni-B catalysts supported on regular mesoporous silicas. The best activity and selectivity were achieved when using SBA-15 as the support, which is attributable to the formation of more uniform active sites due to the unique pore structure of SBA-15.