Synthesis of ordered mesoporous carbon monoliths with bicontinuous cubic pore structure of Ia3d symmetry

Large-diameter-sized mesoporous carbon monoliths with bicontinuous cubic structure of Ia3d symmetry have been synthesized by using mesoporous silica monoliths as hard templates; such carbon monoliths show potential application of advanced electrodes and electrochemical double layer capacitors.     

Highly ordered three-dimensional large-pore periodic mesoporous organosilica with Im3m symmetry

Highly ordered three-dimensional Im3m-type periodic mesoporous organosilica with a cavity size of 9.8 nm has been synthesized under strongly acidic media in the presence of inorganic salts using triblock copolymer F127 as the template and 1,2-bis(trimethoxysilyl)ethane as the organically bridged silica source.     

Immobilization of chiral oxazaborolidine catalyst over highly ordered 3D mesoporous silica with Ia3d symmetry for enantioselective reduction of prochiral ketone

Here we demonstrate for the first time the encapsulation of a chiral oxazaborolidine complex in the 3D mesoporous channels of an amine functionalized KIT-6 material via covalent bonding through a post-synthetic approach. The physico-chemical properties of the pure and immobilized KIT-6 catalysts were obtained by various techniques such as XRD, nitrogen adsorption, HRSEM, UV-Vis diffuse reflectance spectroscopy, and FT-IR spectroscopy. It has been found that the structural stability of the KIT-6 was not affected even after the immobilization of a significant amount of chiral ligand inside the mesoporous channels of the support. However, the values of structural parameters such as the specific surface area and the specific pore volume of the KIT-6 support was significantly lower than the pure KIT-6 support. The chemical interaction between the chiral ligand inside the mesochannels and the KIT-6 support was also confirmed by UV-Vis and FT-IR spectroscopy. The chiral catalytic performance of the immobilized catalysts for the enantioselective reduction of aromatic prochiral ketones was demonstrated and the results were compared with chiral catalyst immobilized supports with uni-dimensional porous structures, such as MCM-41 and SBA-15. Among the catalysts studied, chiral catalyst immobilized KIT-6 showed the highest performance with a high product yield and a high enantioselectivity due to its 3D porous structure with two continuous and interpenetrating systems of chiral channels and an interwoven 3D cylindrical type pores of Ia3d symmetry. The catalyst also exhibited much better recycling capability than other chiral catalyst supported mesoporous materials used in the study.     

A facile aqueous route to synthesize highly ordered mesoporous polymers and carbon frameworks with Ia3d bicontinuous cubic structure

By employing an organic-organic self-assembly in a dilute aqueous solution, novel ordered bicontinuous cubic mesoporous polymers and carbons with Iad symmetry are directly synthesized.     

Cubic Ia3d large mesoporous silica: synthesis and replication to platinum nanowires,carbon nanorods and carbon nanotubes

A new synthesis route to high-quality large mesoporous cubic Ia3d silica is reported, utilizing a triblock copolymer (EO20PO70EO20)-butanol mixture for the structure direction in aqueous solution.     

乙烯基Ia3d介孔硅分子筛的环氧化及其固定化青霉素酰化酶(英文)

采用直接共聚法合成表面含有乙烯基的具有立方相Ia3d结构的介孔硅分子筛(V-ClMS),然后对乙烯基团进行环氧化制备得到表面环氧基功能化的介孔硅分子筛(E-CIMS),采用X射线衍射、N2吸附-脱附、透射电镜、热重分析和13C固体核磁共振对制备的介孔硅分子筛进行了表征.结果表明,表面含有乙烯基的V-ClMS介孔硅分子筛能被一步成功合成,并易于发生环氧化而获得表面环氧基功能化的E-CIMS介孔硅分子筛.将E-CIMS介孔硅分子筛作为载体用于固定化青霉素G酰化酶(PGA),研究了表面环氧基团对固定化PGA初活性和操作稳定性的影响.结果表明,随着表面环氧基团数量的增加,介孔硅分子筛孔径减小,表面疏水性增加,导致载酶量和初活性减小.但介孔硅分子筛表面适量的环氧基团能增强E-CIMS介孔硅分子筛与PGA之间的相互作用,从而提高固定化PGA的操作稳定性.     

Synthesis and characterization of large-pore vinyl-functionalized mesoporous silica SBA-15

Ordered mesoporous silicas SBA-15 with high loadings of pendant vinyl groups have been synthesized via co-condensation of tetraethoxysilane (TEOS) and triethoxyvinylsilane (TEVS) templated with a triblock copolymer.     

Single-crystal mesostructured semiconductors with cubic Ia3d symmetry and ion-exchange properties

If the full scientific and technological potential of mesostructured materials is to be achieved, systems with continuous domains in the form of single crystals or films must be prepared. Here we report a reliable and facile system for making large single-crystal particles of chalcogenido mesostructured materials with a highly organized cubic structure, accessible pore structure, and semiconducting properties. Building blocks with square planar bonding topology, Pt(2+) and [Sn(2)Se(6)](4)(-), in combination with long-chain pyridinium surfactants (C(n)PyBr, n = 18, 20) favor faceted single-crystal particles with the highest possible space group symmetry Ia3d. This is an important step toward developing large single-domain crystalline mesostructured semiconductors and usable natural self-assembled antidot array systems. The tendency toward cubic symmetry is so strong that the materials assemble readily under experimental conditions that can tolerate considerable variation and form micrometer-sized rhombic dodecahedral cubosome particles. The c-C(n)PyPtSnSe materials are the first to exhibit reversible ion-exchange properties. The surfactant molecules can be ion-exchanged reversibly and without loss of the cubic structure and particle morphology. The cubosomes possess a three-dimensional open Pt-Sn-Se framework with a low-energy band gap of approximately 1.7 eV.     

Mesoporous silica with Ia3d cubic structure and good thermal stability

Ia3d cubic mesoporous silica with unusual thermal stability has been synthesized using cetyltrimethylammonium bromide (CTAB) and sugar surfactant dodecyl-beta-D-maltoside (DM) as co-templates.     

PMO[KIT-5]-n: synthesis of highly ordered three-dimensional periodic mesoporous organosilicas with Fm3m symmetry

Divalent surfactant [CH3(CH2)15N(CH3)2(CH2)3N(CH3)3]2+ - 2Br- (C16-3-1) was used as a structure directing agent (SDA) for the synthesis of highly ordered periodic mesoporous organosilicas (PMOs) with cubic Fm3m symmetry from 1,2-bis(triethoxylsilyl)ethane (BTEE) under basic conditions.     

Mechanisms and kinetics for sorption of CO2 on bicontinuous mesoporous silica modified with n-propylamine

We studied equilibrium adsorption and uptake kinetics and identified molecular species that formed during sorption of carbon dioxide on amine-modified silica. Bicontinuous silicas (AMS-6 and MCM-48) were postsynthetically modified with (3-aminopropyl)triethoxysilane or (3-aminopropyl)methyldiethoxysilane, and amine-modified AMS-6 adsorbed more CO(2) than did amine-modified MCM-48. By in situ FTIR spectroscopy, we showed that the amine groups reacted with CO(2) and formed ammonium carbamate ion pairs as well as carbamic acids under both dry and moist conditions. The carbamic acid was stabilized by hydrogen bonds, and ammonium carbamate ion pairs formed preferably on sorbents with high densities of amine groups. Under dry conditions, silylpropylcarbamate formed, slowly, by condensing carbamic acid and silanol groups. The ratio of ammonium carbamate ion pairs to silylpropylcarbamate was higher for samples with high amine contents than samples with low amine contents. Bicarbonates or carbonates did not form under dry or moist conditions. The uptake of CO(2) was enhanced in the presence of water, which was rationalized by the observed release of additional amine groups under these conditions and related formation of ammonium carbamate ion pairs. Distinct evidence for a fourth and irreversibly formed moiety was observed under sorption of CO(2) under dry conditions. Significant amounts of physisorbed, linear CO(2) were detected at relatively high partial pressures of CO(2), such that they could adsorb only after the reactive amine groups were consumed.     

Amine decorated 2d hexagonal and 3d cubic mesoporous silica nanoparticles: A comprehensive dissolution kinetic study in simulated and biorelevant media

Highly ordered Bexarotene (BXR) encapsulated mesoporous silica nanoparticles in particular bare and amine functionalized MCM-41 and MCM-48 were designed employing a novel impregnation solvent evaporation strategy. The outcomes unveiled successful synthesis of mesoporous assembly having 2?D hexagonal and 3?D cubic framework for MCM-41 and MCM-48 respectively withholding large surface area, optimum pore size, pore volume along with uniform particle size distribution. Additionally, SXRD and TEM findings divulged retention of characteristic mesoporous features regardless of surface modification and drug incorporation. Eventually the release profile and release kinetics results in different dissolution media demonstrated complete drug release in simulated intestinal fluid (SIF) within 75?min and 45?min from BXR-41 and BXR-48 along with 3.33 and 5 fold increment in dissolution profile. Furthermore, lack of any interaction between gelatin of hard capsule shell and amine group in presence of enzyme were justified from the indistinguishable release pattern in enzyme free and enzyme enriched SIF media. The divergent release pattern in fed and fasted state condition having a higher release in former media strongly directs towards taking medicine after meal. Finally the release kinetics study exhibited Weibull and Higuchi model as a best fit models for bare and amine coated BXR nanoparticles respectively.     

Non-surfactant synthesis of mesoporous silica with dye as template

A novel non-suffactant method was described to synthesize mesoporous silica using dye basic fuchsin as template.Chemical reactions were introduced into the formation of mesopores rather than the weak electrostatic or hydrogen-bonding interactions in the traditional surfactant routes.The reactant composition was found to be crucial to the pore structure of objective product.The formation mechanism of mesopore was also proved.     

Stability of small mesoporous silica nanoparticles in biological media

In this work, sub-50 nm pegylated mesoporous silica nanoparticles prepared with hydrothermal treatment are shown to have long-term stability in various media at both room and physiological temperature. Compared to bare mesoporous silica nanoparticles, the highly pegylated mesoporous silica nanoparticles show significantly improved biocompatibility and decreased macrophage uptake, making these nanoparticles viable for in vivo stealth drug delivery applications.     

Functionalisation of mesoporous silica nanoparticles with 3-isocynatopropyltrichlorosilane

The functionalisation of Mesoporous Silica Nanoparticles (MSN) with the isocyanate group was carried out. The excellent reactivity of 3-isocynanatopropyltrichlorosilane allowed its grafting on the surface of MSN in mild conditions. Further reaction with different nucleophiles bearing primary amino groups led to the formation of a urea linkage and thus the covalent grafting of the nucleophiles to the MSN surface.     

Microfluidization-assisted synthesis of hollow mesoporous silica nanoparticles

Hollow mesoporous silica nanoparticles (HMSNs) with the diameter in range of 100–500 nm and the wall thickness of about 50 nm were synthesized by templates of cetyltrimethylammonium bromide under the assistant of microfluidization technique. These HMSNs were demonstrated effective drug loading and a pH-responsive drug release.