Hybrid Porous Materials with High Surface Area Derived from Bromophenylethenyl‐Functionalized Cubic Siloxane‐Based Building Units

Abstract

Sonogashira cross-coupling of bromophenylethenyl-terminated cubic, double four-ring, siloxane cages with di-/triethynyl compounds results in microporous poly(ethynylene aryleneethenylene silsesquioxane) networks, simply termed as polyorganosiloxane networks (PSNs). In comparison with porous organic polymers reported previously, these PSNs show relatively high surface area and comparable thermal stability. Their apparent BET specific surface areas vary in the range of 850-1040 m(2) g(-1) depending on the length and the connectable sites of the ethynyl compounds. Analyses of pore size distribution revealed bimodal micropores with relatively narrow distribution. The degree of cross-linking affects the degree of cleavage of the siloxane bonds, and this suggests that partial cleavage of the siloxane cages is mainly a result of cage distortion. Hydrogen adsorption was performed to evaluate potential of the PSNs as hydrogen storage media. Uptakes of up to 1.19 wt% at 77 K and 760 Torr and initial isosteric heats of adsorption as high as 8.0 kJ mol(-1) were observed. These materials have been obtained by a combination of structural, synthetic organic, and materials chemistry, which can exploited to synthesize porous hybrid materials with specifically designed structures and functions.

Poly(L‐lysine) Brush–Mesoporous Silica Hybrid Material as a Biomolecule‐Based Adsorbent for CO2 Capture from Simulated Flue Gas and Air

“…This phenomenon is more pronounced under low-pressure conditions, in which the neighboring pairs of amines are the predominant adsorption sites. [44] In addition, it is well known that the isosteric heats of adsorption decrease with increasing surface coverage of adsorbed species, [12,45] which implies that the heat of adsorption becomes a preponderant factor at very low concentration (i.e., low coverage). Also, the heat of CO 2 adsorption onto silica-supported amines decreases with decreasing amine loading, due to the increased physisorption that occurs on the bare support surface at low amine loadings.…”

Construction of Hybrid Porous Materials from Cubic Octavinylsilsesquioxane through Friedel–Crafts Reaction Using Tetraphenylsilane as a Concentrative Crosslinker

“…[5][6][7][8][9] Polyhedral oligomeric silsesquioxnes, with three-dimensional nanometer-sized inorganic-organic hybrid structures, are particularly suitable monomers, because they are rigid, highly functional, and exceptionally robust with respect to heat and water. [10][11][12] Some micro-mesoporous polymers from POSS-based precursors have been prepared through various methods including hydrosilylation, [13] Sonogashira coupling reaction, [6,7] Yamamoto coupling reaction, [8] Heck [9] and Friedel-Crafts reaction, [14] radical polymerization, [15,16] and others. [17][18][19] The use of rigid or stereocontorted monomers as building blocks, especially tetrahedral monomers, is an efficient means by which to design porous polymers with large specific surface areas.…”

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

“…weight loss of ca. 1.8 wt %w as observed, which is due to dehydration-condensation of silanols in Q 2 pillars.F rom the results above,t he chemical composition of KCS-2 is considered to be j Na 12 6 ], in which x is estimated at 18 for amildly dehydrated sample and at 32 for ah ydrated sample.…”

“…[4] Also,s everal covalently linked nanoporous materials having zeolite topology,f or example,J UC-Z1 [5] (LTA-type) and PSN-1 [6] (ACO-type), were synthesized by means of ac ross-coupling reaction. 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.…”