e hydrogen-bonded species are eliminated at elevated temperatures under vacuum whereas the isolated ones remain. Loading C60 in the MCM-41 materials greatly changes their dehydroxylation behavior. When the MCM-41:C60 weight ratio is 10:1, at about 400℃ under vacuum, the isolated silanols are reduced to a certain degree whereas the hydrogen-bonded hydroxyls become more resistant to thermal treatment by comparison with those in the parent C60-free samples. Increasing the loading amount of C60 to a MCM-41:C60 weight ratio of 10:3 results in complete removal of both isolated and hydrogen-bonded silanols, at about 350℃. However, the two MCM-41 samples exhibit different infrared spectra at lower evacuation temperatures in the presence of C60, indicative of a discrepancy in the dehydroxylation process between them. It is postulated that during the dehydroxylation, C60 captures hydroxyls from the silanol groups of MCM-41 to form C-H and C-OH species, followed by condensation of the C-OH groups and/or combination of C-OH with C-H.

A new layered ammonium cobalt-zinc phosphate has been synthesized under solvothermal conditions at 160℃ and the structure solved using room-temperature single-crystal X-ray diffraction data. (NH4[Zn2-xCox(PO4)(HPO4)] (x 0.12), Mr) 339.75, triclinic, space group P-1, a) 5.237(1) Å, b) 8.949(1) Å3, c) 9.728(1) Å, R) 74.99(1)°, â) 77.64(1)°, ç) 72.92(1)°, V) 416.19(1) Å3, Z) 2, 1511 observed data measured with I > 3ó(I), R) 4.31% and Rw) 4.67%). The structure consists of MO4 (M) Zn, Co), PO4, and PO3(OH) tetrahedra linked to form buckled layers containing three-and four-membered rings between which ammonium cations reside. A network of hydrogen bonds involving both interlayer and layer-toammonium interactions holds the phosphate layers together.

A family of lamellar aluminophosphates designated APO-Ln (L stands for lamellar and n ) 6, 8, 10, 12, the number of carbon atoms for the occluded template molecules) was synthesized from a mixture of phosphoric acid, aluminum triisopropoxide, ethylene glycol and an unbranched primary alcohol in the presence of an amine as the structure-directing template. The compounds were characterized by X-ray powder diffraction, scanning electron microscopy, MAS NMR spectroscopy, differential thermal, and thermogravimetric analyses. The inorganic layers of APO-Ln are composed of PO4, AlO4, and AlO6 structural units, and the ratio of the octahedral Al to the tetrahedral Al in the as-synthesized compounds is about 1:1. APO-Ln exhibit a distinct weight loss when treated at elevated temperatures, and upon dehydration they adsorb a considerable amount of water. Dehydration-rehydration for APOLn materials is reversible with the dehydrated samples containing almost only tetrahedrally coordinated aluminum.

Hydrothermal synthesis of two new fluorinated indium phosphates [InPO4F(Hen)] and [In5P4F3O16(en)3(OH2)2] is carried out in the system In2O3-P2O5-en-HF-H2O (en = ethylenediamine); these have two-and three-dimensional inorganic frameworks respectively, with the latter having ten-membered ring channels spanned by coordinated en; the fluorides bridge exclusively between indium ions and may be linear or bent.

The successful synthesis of M41S materials,[1,2] a new family of novel silicates with uniform mesopores, opened a vast range of applications[3-7] in catalysis, sorption, molecular recognition, electronics, and photochemistry. One of the members of this family of materials is MCM-41, which contains a hexagonal array of mesopores with a pore diameter of 20 100,A depending on the conditions of its synthesis. It is postulated[2] that the inorganic walls around the mesopores of MCM-41 are constructed of disordered SiO4 tetrahedral units, as is also the case for amorphous silicates. NMR studies[2,8] reveal that MCM-41 contains many silanol groups both before and after the template molecules have been removed. These silanols may act as functional groups in chemical reactions or can be utilized to attach molecules having other functional groups. Although the structure and stability of the pores are well understood, little is known about the nature of the silanol groups in MCM-41. To shed some light on this, we monitored the IR absorptions of the silanol groups in template-free MCM-41 as a function of evacuation temperature before and after silylation by chlorotrimethylsilane (CTMS) and chlorotriphenylsilane (CTPS).