Hexagonal and Cubic Thermally Stable Mesoporous Tin(IV) Phosphates with Acidic and Catalytic Properties

Abstract

Since the initial work of Mobil researchers on the synthesis of mesoporous silica, [1] a lot of work has been devoted to extend the composition of mesoporous materials to metal oxides other than silica for applications in acid, redox catalysis, or photocatalytic processes. [2±4] Polyhedron 1998, 17, 845 ± 850; b) V. L. Pecoraro, G. B. Wong, T. A. Kent, K. N. Raymond, J. Am. Chem. Soc. 1983, 105, 4617 ± 4623. [16] X-ray crystal data for 1: C 36 H 63 CrN 6 , M r 589.85, triclinic, P1 ≈ , a 9.9754(17), b 12.707(2), c 16.687(3) ä, a 77.228(3), b 75.734 (3), g 70.655(4)8, V 1911.5(6) ä 3 , Z 2, 1 calcd 1.025 g cm À3 , m 0.326 mm À1 , 8755 independent reflections harvested from 2450 frames of data collected at 20 s per frame and 0.28 between frames yielded 13 711 integrated intensities, R int 0.029. All data were included in the refinement. For I > 2s(I), R 1 0.0685 and wR 2 0.1856; including weak data R 1 0.1585 and wR 2 0.2141. Siemens/ Bruker P4-CCD, Mo Ka radiation (l 0.7107 ä), graphite monochromator, 2V max 56.58, T 295(2) K. Suitable crystals for single-crystal X-ray analysis were selected and mounted inside thin-walled capillaries in a dry box under nitrogen atmosphere. Data collection and integration used the Bruker SMART and SAINT software. Empirical absorption corrections were calculated using the program SA-DABS. [17] Solution and refinement used the programs SHELXS [17] and SHELXL-93. [17] All non-hydrogen atoms were described anisotropically. Hydrogen atoms were placed in calculated positions. The 3,5-di-tert-butylpyrazolato ligands typically show severe disorder in the tert-butyl groups, which results in modeling difficulties and high R values. However, other criteria of chemical and crystallographic reasonableness show these to be acceptable structural models. CCDC-175570 (1) and CCDC-175571 (2 ¥ (C 6 H 14 ) 0.5 ) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or from the Cambridge Crystallographic Data Centre, 12, Union Road, ) are gratefully acknowledged for their collaboration in NMR and Mˆssbauer experiments.

Influence of hydrothermal, microwave and mechanochemical treatment of tin phosphate on porous structure and catalytic properties

“…Bulk and supported tin phosphate with a Sn/P ratio of 1:2 have been previously showed to be effective as acid catalysts, including in aldol condensation [3][4][5][6][7]36]. Therefore, some modified SnP samples were tested in the model process of gas phase aldol condensation of AcA with FA to evaluate the efficiency of tin phosphates modification leading to different porous structure and thermal stability.…”

“…Acid tin phosphates (SnP) belong to a family of amorphous and crystalline phosphates of tetravalent metals with a general formula of Me(HPO 4 ) 2 •nH 2 O. Being solid acids [1,2], they find application in catalysis [3][4][5][6][7], adsorption of cations [2,8,9], electrochemical processes [10]. All these applications suggest that SnP materials possess large specific surface area and developed porosity.…”

“…Firstly, template synthesis allows to prepare mesostructured mesoporous materials possessing higher specific surface area and pore volume. For instance, mesoporous tin phosphate has specific surface area, pore volume, and mesopore size within 122-247 m 2 • g −1 , 0.2-0.6 cm 3 • g −1 and 2.5-10.4 nm, respectively [3,5,10,18]. However, this technique is quite complicated and expensive to implement.…”

“…For instance, the milling (mechanochemical treatment) of wet silica gel and dried xerogel in water results in an increase of the specific surface area (from 642 to 700-900 m 2 • g −1 ) [17]. Besides, the pore volume also increases from 0.3 to 0.5 cm 3 • g −1 . Therefore, modification of wet silica gel allows to prepare the samples with such a homogenous mesoporous structure as for MCM-41 [17].…”

A Mesoporous/Crystalline Composite Material Containing Tin Phosphate for Use as the Anode in Lithium‐Ion Batteries

“…However, the meso periodicity is contracted; the corresponding d spacing of the annealed mesoporous tin phosphate is 3.5±0.3 nm 6. 9, 10 The high‐angle XRD pattern of the annealed sample clearly shows the presence of Sn 2 P 2 O 7 (inset of Figure 1 b). 4 The crystal size of the sample both before and after annealing, calculated using the Scherrer formula, was estimated to be approximately 100 nm,11 which is two orders of magnitude larger than the wall thickness of the pure mesoporous phase (ca.…”