Synthesis of new microporous layered organic–inorganic hybrid nanocomposites by alkoxysilylation of a crystalline layered silicate, ilerite

Abstract

We have developed microporous organic-inorganic hybrid nanocomposites by alkoxysilylation of 4,49-biphenyl-bridged alkoxysilane compounds, which contain triethoxysilyl, methyldiethoxysilyl, and dimethylethoxysilyl groups at each end of the 4,49-biphenylene unit ((CH 3 ) n (C 2 H 5 O) 32n -Si-C 12 H 8 -Si-(OC 2 H 5 ) 32n (CH 3 ) n , n = 0, 1, or 2, abbreviated as BESB(0), BESB(2), or BESB(4), respectively, where the number in parentheses indicates the number of methyl groups in these molecules), in the interlayer of a crystalline layered silicate, ilerite. XRD, 29 Si solid-state NMR and fluorescence spectroscopy revealed the immobilization and bridging formation of the BESB molecules between the silicate layers by condensation, not only with H-ilerite, but also with the BESB molecules. The interlayer structures exhibited different molecular arrangements. BESB(0) and BESB(4) molecules are present as a monolayer arrangement in which BESB(0) molecules form the oligomeric species caused by close stacking like a dimer. BESB(2) molecules form mainly bilayer-like aggregates in the interlayer. The structural differences are caused by the different reactivities of the BESB molecules, which control their polymerization in the interlayer. The resultant BESB(0)-and BESB(2)-ilerite had high microporosity with BET surface areas (508 and 578 m 2 g 21 for BESB(0)-and BESB(2)-ilerite, respectively). The micropores showed higher toluene adsorptivity than several other porous silica materials due to the successful surface modification. Consequently, this approach provides a new method for constructing novel microporous nanocomposites, the key to improved selectivity and activity in separation and catalytic applications.

One-pot synthesis of hierarchical porous layered hybrid materials based on aluminosilicate sheets and organic functional pillars

“…These approaches have been very effective to heterogenize different homogeneous catalysts without appreciable activity loss. 22,23 Those methodologies were validated by the recent preparation of multifunctional zeolitic hybrid materials. Specifically, bi-functional organic-inorganic layered materials were synthesized by the intercalation of arylic silsesquioxane molecules between inorganic zeolitic MWW layers.…”

Amphiphilic Organic–Inorganic Hybrid Zeotype Aluminosilicate like a Nanoporous Crystallized Langmuir–Blodgett Film

“…Besides,o rganicinorganic hybrid porous materials can be prepared from various layered silicates or clay minerals [7][8][9][10] and their structures are formed by employing al arge bulky organic molecule like an organosilane as apillar unit in the interlayer space.R ecently,B ellussi and co-workers have developed as eries of original crystalline aluminosilicates called ECS using ap henylene-bridged bis(triethoxysilyl)benzene (BTEB), some of which showed microporosity. [11] We also synthesized organic-inorganic hybrid materials using BTEB after these precedents.I no ur case,h owever, another silicon source,t etraethyl orthosilicate (TEOS), was used together with BTEB aiming at additional physicochemical properties.Ananoporous crystalline aluminosilicate KCS-2 is one of the materials obtained by this approach, [12] and we have succeeded in solving its crystal structure by powder X-ray diffraction (PXRD) analysis (analysis procedures and crystallographic information are summarized in the Supporting Information (SI);additionally,the structural data can be obtained free of charge from the Fachinformationszentrum Karlsruhe (76344 Eggenstein-Leopoldshafen,G ermany;c rysdata@fiz-karlsruhe.de) by quoting the depository number CSD-429246).…”

Microporous Organic-inorganic Nanocomposites as the Receptor in the QCM Sensing of Toluene Vapors

“…This corresponded to a d-spacing value of 1.61 nm. The layer thickness of ilerite is 0.74 nm, 18 and hence the resultant interlayer distance was evaluated as 0.87 nm. The interlayer spacing was retained by the BESB molecules which acted as "pillars" between the silicate sheets.…”

“…18 The bipheneylene-pillared layered materials were synthesized by the following protocol. The starting material, ilerite, was protonated and mixed with n-hexane.…”

“…17,18 The structure of the synthesized material, which belongs to a new type of organic-inorganic nanocomposites, consists of alternately stacked inorganic nanosheets and organic molecule monolayers. The novelty of these materials lies in an open framework structure in the interlayers where the biphenylene units retain spaces at molecular dimensions between the silicate sheets.…”