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Qihua Yang - One of the best experts on this subject based on the ideXlab platform.
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Functionalized Periodic Mesoporous Organosilicas: Hierarchical and Chiral Materials
Science China Chemistry, 2010Co-Authors: Qihua Yang, Jian Liu, Lei ZhangAbstract:The integration of organic and inorganic fragments within the pore walls of the periodic Mesoporous Organosilicas (PMOs) represents one of the recent breakthroughs in material science. The resulting PMOs are promising materials for applications in such areas as catalysis, adsorption, separation and drug-delivery. We summarize here the recent progress made in the synthesis of PMOs with hierarchical structures and large functional groups, with special emphasis on the chiral Mesoporous Organosilicas and their potential applications as novel chiral solids in heterogeneous asymmetric catalysis.
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catalytic applications of sulfonic acid functionalized Mesoporous Organosilicas with different fraction of organic groups in the pore wall
Journal of Porous Materials, 2009Co-Authors: Jian Liu, Jie Yang, Qihua YangAbstract:Organosulfonic acid functionalized Mesoporous Organosilicas with different fraction of organic groups in the pore wall was synthesized in the presence of P123 (EO20PO70EO20) by controlling the molar ratio of tetramethoxysilane (TMOS) to 1,2-bis(trimethoxysilyl)ethane (BTME) in the initial mixture during the co-condensation process of silane precursors in acidic medium. Structural characterizations (X-ray diffraction, nitrogen sorption analysis, and transmission electron microscopy) show that all materials have ordered hexagonal Mesoporous structure with large pore diameter (7–9 nm). The existence of ethane and sulfonic acid groups in the material was verified by 29Si MAS and 13C CP MAS NMR and X-ray photoelectron spectroscopy (XPS). The Mesoporous solid acids can adsorb both water and hexane (the adsorption capacity for water and hexane is 240 and 600 mg/g, respectively) due to the existence of surface hydroxyl groups, propyl sulfonic acid group, and the ethane moiety. These Mesoporous solid acids are efficient catalysts for the dehydration of 1-butanol and the hydration of propylene oxide (PO).
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functionalized periodic Mesoporous Organosilicas for catalysis
Journal of Materials Chemistry, 2009Co-Authors: Qihua Yang, Jian Liu, Lei ZhangAbstract:Periodic Mesoporous Organosilicas (PMOs), one of most advanced organic–inorganic hybrid materials, have attracted much research attention because of their combined advantages of ordered Mesoporous structure and fusion of organic and inorganic fragments within the pore wall. PMOs with diverse mesostructures, morphologies and compositions have emerged in the past few years, and shown unprecedented properties. Recent years have seen the great progress in the controlled synthesis of functionalized PMOs towards specific application demands, particularly in catalysis. This Feature Article describes selected examples of the synthesis of functionalized PMOs for catalytic applications in the past few years.
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chiral Mesoporous Organosilicas with r binol integrated in the framework
Microporous and Mesoporous Materials, 2009Co-Authors: Lei Zhang, Jian Liu, Jie Yang, Peiyuan Wang, Qihua YangAbstract:Abstract Bifunctionalized chiral Mesoporous Organosilicas with both R -(+)-Binol and ethylene moieties integrated in the framework was synthesized by co-condensation of 1,2-bis(trimethoxysilyl)ethane (BTME) and ( R )-2,2′-dimethoxy-6,6′-di-[(2-trimethoxysilyl)-ethenyl]-1,1′-binaphthyl ( R -MMB) in acidic medium using P123 as template for the first time. With the molar fraction of R -MMB increasing from10 to 20% in the initial mixture, the mesostructure of the material changes from a well-ordered 2D hexagonal mesostructure to a worm-like structure. The materials have a pore diameter in the range of 4.8–5.2 nm with BET surface areas varying from 356 to 894 m 2 g −1 . The results of FT-IR, 13 C and 29 Si solid-state NMR shows the integration of the organic groups in the material though some Si–C bond cleavage was observed during the synthesis. The circular dichroism spectrum of the material dissolved in NaOH confirms that the chirality of R -(+)-Binol in the material remains unchanged compared with the molecular precursor. The hydroxyl groups of the R -(+)-Binol units were liberated by treatment of the material with BBr 3 . The resultant materials were used in Ti-promoted asymmetric addition of diethylzinc to benzaldehyde. High catalytic activity (99%) with moderate enantioselectivity (39.7%) was achieved, which also confirms that R -Binol was incorporated in the PMOs successfully.
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Mesoporous Organosilicas containing disulfide moiety synthesis and generation of sulfonic acid functionality through chemical transformation in the pore wall
Microporous and Mesoporous Materials, 2008Co-Authors: Jian Liu, Lei Zhang, Jie Yang, Qihua YangAbstract:Abstract Mesoporous Organosilicas with disulfide moiety bridged in the pore wall have been synthesized by co-condensation of bis[3-(triethoxysilyl)propyl]disulfide (BTPDS) and tetramethoxysilane (TMOS) in acetic acid/sodium acetate buffer solution (HAc–NaAc, pH 4.4), using nonionic surfactant P123 as the template. With the molar percent of BTPDS increasing, the mesostructure of the resultant material transforms from highly ordered 2-D hexagonal structure to cellular foam structure. The disulfide moiety could be transferred to sulfonic acid functionality by a simple post-oxidation method. The structural characterizations show that the mesostructure changes during the oxidation step especially for the materials with high content of disulfide moiety. In the esterification of aliphatic acid and ethanol, the oxidized materials show higher yield than the conventional heterogeneous solid acids such as zeolites and sulfonic acid resin. Comparisons of the structural properties and the catalytic results of the materials show that a large pore diameter and low surface hydrophilicity are required to obtain high catalytic activity.
Jian Liu - One of the best experts on this subject based on the ideXlab platform.
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clickable periodic Mesoporous Organosilicas synthesis click reactions and adsorption of antibiotics
Chemistry: A European Journal, 2014Co-Authors: Jinsuo Gao, Xueying Zhang, Feng Tan, Yaobin Zhang, Xie Quan, Jian LiuAbstract:Pharmaceutical antibiotics are not easily removed from water by conventional water-treatment technologies and have been recognized as new emerging pollutants. Herein, we report the synthesis of clickable azido periodic Mesoporous Organosilicas (PMOs) and their use as adsorbents for the adsorption of antibiotics. Ethane-bridged PMOs, functionalized with azido groups at different densities, were synthesized by the co-condensation of 1,2-bis(trimethoxysilyl) ethane (BTME) and 3-azidopropyltrimethoxysilane (AzPTMS), in the presence of nonionic-surfactant triblock-copolymer P123, in an acidic medium. Four different alkynes were conjugated to azide-terminated PMOs by means of an efficient click reaction. The clicked PMOs showed improved adsorption capacity (241 mu g g(-1)) for antibiotics (ciprofloxacin hydrochloride) compared with azido-functionalized PMOs because of the enhanced pi-pi stacking interactions. These results indicate that click reactions can introduce multifunctional groups onto PMOs, thus demonstrating the great potential of PMOs for environmental applications.
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Functionalized Periodic Mesoporous Organosilicas: Hierarchical and Chiral Materials
Science China Chemistry, 2010Co-Authors: Qihua Yang, Jian Liu, Lei ZhangAbstract:The integration of organic and inorganic fragments within the pore walls of the periodic Mesoporous Organosilicas (PMOs) represents one of the recent breakthroughs in material science. The resulting PMOs are promising materials for applications in such areas as catalysis, adsorption, separation and drug-delivery. We summarize here the recent progress made in the synthesis of PMOs with hierarchical structures and large functional groups, with special emphasis on the chiral Mesoporous Organosilicas and their potential applications as novel chiral solids in heterogeneous asymmetric catalysis.
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catalytic applications of sulfonic acid functionalized Mesoporous Organosilicas with different fraction of organic groups in the pore wall
Journal of Porous Materials, 2009Co-Authors: Jian Liu, Jie Yang, Qihua YangAbstract:Organosulfonic acid functionalized Mesoporous Organosilicas with different fraction of organic groups in the pore wall was synthesized in the presence of P123 (EO20PO70EO20) by controlling the molar ratio of tetramethoxysilane (TMOS) to 1,2-bis(trimethoxysilyl)ethane (BTME) in the initial mixture during the co-condensation process of silane precursors in acidic medium. Structural characterizations (X-ray diffraction, nitrogen sorption analysis, and transmission electron microscopy) show that all materials have ordered hexagonal Mesoporous structure with large pore diameter (7–9 nm). The existence of ethane and sulfonic acid groups in the material was verified by 29Si MAS and 13C CP MAS NMR and X-ray photoelectron spectroscopy (XPS). The Mesoporous solid acids can adsorb both water and hexane (the adsorption capacity for water and hexane is 240 and 600 mg/g, respectively) due to the existence of surface hydroxyl groups, propyl sulfonic acid group, and the ethane moiety. These Mesoporous solid acids are efficient catalysts for the dehydration of 1-butanol and the hydration of propylene oxide (PO).
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functionalized periodic Mesoporous Organosilicas for catalysis
Journal of Materials Chemistry, 2009Co-Authors: Qihua Yang, Jian Liu, Lei ZhangAbstract:Periodic Mesoporous Organosilicas (PMOs), one of most advanced organic–inorganic hybrid materials, have attracted much research attention because of their combined advantages of ordered Mesoporous structure and fusion of organic and inorganic fragments within the pore wall. PMOs with diverse mesostructures, morphologies and compositions have emerged in the past few years, and shown unprecedented properties. Recent years have seen the great progress in the controlled synthesis of functionalized PMOs towards specific application demands, particularly in catalysis. This Feature Article describes selected examples of the synthesis of functionalized PMOs for catalytic applications in the past few years.
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chiral Mesoporous Organosilicas with r binol integrated in the framework
Microporous and Mesoporous Materials, 2009Co-Authors: Lei Zhang, Jian Liu, Jie Yang, Peiyuan Wang, Qihua YangAbstract:Abstract Bifunctionalized chiral Mesoporous Organosilicas with both R -(+)-Binol and ethylene moieties integrated in the framework was synthesized by co-condensation of 1,2-bis(trimethoxysilyl)ethane (BTME) and ( R )-2,2′-dimethoxy-6,6′-di-[(2-trimethoxysilyl)-ethenyl]-1,1′-binaphthyl ( R -MMB) in acidic medium using P123 as template for the first time. With the molar fraction of R -MMB increasing from10 to 20% in the initial mixture, the mesostructure of the material changes from a well-ordered 2D hexagonal mesostructure to a worm-like structure. The materials have a pore diameter in the range of 4.8–5.2 nm with BET surface areas varying from 356 to 894 m 2 g −1 . The results of FT-IR, 13 C and 29 Si solid-state NMR shows the integration of the organic groups in the material though some Si–C bond cleavage was observed during the synthesis. The circular dichroism spectrum of the material dissolved in NaOH confirms that the chirality of R -(+)-Binol in the material remains unchanged compared with the molecular precursor. The hydroxyl groups of the R -(+)-Binol units were liberated by treatment of the material with BBr 3 . The resultant materials were used in Ti-promoted asymmetric addition of diethylzinc to benzaldehyde. High catalytic activity (99%) with moderate enantioselectivity (39.7%) was achieved, which also confirms that R -Binol was incorporated in the PMOs successfully.
Geoffrey A. Ozin - One of the best experts on this subject based on the ideXlab platform.
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Water Repellent Periodic Mesoporous Organosilicas
ACS nano, 2011Co-Authors: Wendong Wang, Daniel Grozea, Sandeep Kohli, Douglas D. Perovic, Geoffrey A. OzinAbstract:This paper demonstrates for the first time thermally induced gradual hydrophobization, monitored quantitatively by ellipsometric porosimetry, of four prototypical periodic Mesoporous Organosilicas (PMOs) that are tailored through materials chemistry for use as low-dielectric-constant (low k) materials in microprocessors. Theoretical aspects of this quantification are briefly discussed. A comparison of structural, mechanical, dielectric, and hydrophobic properties of ethane, methane, ethene, and 3-ring PMOs is made. Particularly, ethane, methane, and 3-ring PMOs show impressive water repellency at post-treatment temperatures as low as 350 °C, with corresponding Young's modulus values greater than 10 GPa and k values smaller than 2, a figure of merit that satisfies the technological requirements of future generation microchips.
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synthesis and characterization of highly amine functionalized Mesoporous Organosilicas by an all in one approach
Journal of Materials Chemistry, 2005Co-Authors: Rebecca Voss, Arne Thomas, Markus Antonietti, Geoffrey A. OzinAbstract:Mesoporous Organosilicas (MOs) represent a promising class of organic–inorganic nanocomposites for a broad range of applications like catalysis, sensing, separation, or microelectronics. Their distinct feature is the presence of organic groups incorporated into the channel walls of a Mesoporous structure. Here, we present a convenient “all-in-one” approach using silsesquioxane surfactant precursors for the functionalization of the channel walls with primary amine groups. The monomer is made by a hydroboration/aminolysis sequence on the base of a commercial monomer, with the template bound to the functionalization site by hydroboration and released after silica condensation and aminolysis. This combination ensures both the placement of the amine groups exclusively along the channel interface as well as optimal use of the template.
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challenges and advances in the chemistry of periodic Mesoporous Organosilicas pmos
Journal of Materials Chemistry, 2005Co-Authors: William J Hunks, Geoffrey A. OzinAbstract:The merger of materials synthesis, organic synthesis, and supramolecular chemistry has lead to a plethora of hybrid organic–inorganic materials with control over the molecular organization, nanoscale periodicity, and macroscopic morphology. Self-assembly of polymeric precursors can be directed by micelle templates, or through microphase separation of block copolymers. This has provided a pathway to new materials whose hierarchical structure determines material properties and function. Periodic Mesoporous Organosilicas (PMOs), which are composed of bridge-bonded silsesquioxanes organized into a Mesoporous architecture, have emerged as promising materials for nanotechnology applications. This article provides an overview of PMOs and describes the challenges, problems and our predictions for the future of these intriguing solid-state materials.
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single source precursors for synthesizing bifunctional periodic Mesoporous Organosilicas
Advanced Functional Materials, 2005Co-Authors: William J Hunks, Geoffrey A. OzinAbstract:A new class of bifunctional periodic Mesoporous Organosilicas (PMOs) composed of organosilicate building blocks with two different silicon sites have been synthesized from the single-source bifunctional organosilica precursors tris(triethoxysilyl-ethyl)ethoxysilane and bis(triethoxysilylethyl)diethoxysilane, respectively denoted MT 3 -PMO and DT 2 -PMO. The synthesis of these PMOs is achieved by the co-assembly of a triblock-copolymer Pluronic P123 template with the bifunctional organosilica precursor under acid-catalyzed and inorganic-salt-assisted conditions. After template removal through solvent extraction, the MT 3 -PMO and DT 2 -PMO so obtained show well-ordered mesopores and display large pore diameters (6-7 nm) and pore volumes (0.6-0.8 cm 3 g - 1 ) with a narrow pore-size distribution and high surface areas (700-800 m 3 g - 1 ).
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Hybrid Periodic Mesoporous Organosilicas
Advanced Functional Materials, 2005Co-Authors: Wesley Whitnall, Tewodros Asefa, Geoffrey A. OzinAbstract:In this study we report the synthesis of a new class of materials called hybrid periodic Mesoporous Organosilicas (HPMOs). By coupling a silsesquioxane precursor through at least two chemical linkages to the mesopore walls of a pre-existing periodic Mesoporous silica (PMS) or periodic Mesoporous organosilica (PMO). Many of the problems of a conventional PMO material can be avoided while ensuring efficient use of the bridging organic functional groups of the silsesquioxane. We demonstrate this concept for PMS by anchoring various silsesquioxanes, such as ethene and ethane silsesquioxanes, to the mesopore walls of the PMS. The addition of anchored silsesquioxane monolayers and multilayers to the mesopore walls also allows for the strict control of the diameter of the mesopore as well as the mesopore wall thickness in the final HPMO material. Additionally it is shown that having the silsesquioxane located solely on the surface of the mesopores in HPMOs gives increased chemical accessibility of the organic bridge-bonded moiety when compared with their PMO counterparts containing the bridge-bonded organic both on the surface and within the pore walls.
Jie Yang - One of the best experts on this subject based on the ideXlab platform.
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pore size optimized periodic Mesoporous Organosilicas for the enrichment of peptides and polymers
RSC Advances, 2013Co-Authors: Kun Qian, Jie Yang, Fang Liu, Xiaodan Huang, Siddharth Jambhrunkar, Pei YuanAbstract:The enrichment of peptides is a key technique in mass spectrometry based proteomics and peptidomics. The tailored design of Mesoporous materials with an optimum pore size for highly-efficient enrichment of target molecules is a challenging issue. Herein, a series of periodic Mesoporous Organosilicas (PMOs) are synthesized with the same structural symmetry (p6mm) and similar morphology, while the pore sizes are finely adjusted from 2.6 to 7.3 nm. Their enrichment performance for a standard E7 peptide (molecular weight 1120.6 Da) is investigated via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). It is found that PMO with the mesopore size of 5.8 nm exhibits the highest enrichment performance towards the E7 peptide. Moreover, a block copolymer (Brij 78) with the similar molecular weight (1150.8 Da) to E7 is also used to further study the influence of mesopore size upon the enrichment efficiency. It is shown that PMO with the pore size of 5.8 nm still holds the best enriching ability towards Brij 78 at low concentrations. The adsorption capacity of the PMOs for Brij 78 are further studied at high concentrations, showing a dependence on both the pore volume and pore size. This research may shed light on advanced enrichment and analysis of various peptides and polymers using designed nanoporous materials, an important topic in both material and biological science.
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catalytic applications of sulfonic acid functionalized Mesoporous Organosilicas with different fraction of organic groups in the pore wall
Journal of Porous Materials, 2009Co-Authors: Jian Liu, Jie Yang, Qihua YangAbstract:Organosulfonic acid functionalized Mesoporous Organosilicas with different fraction of organic groups in the pore wall was synthesized in the presence of P123 (EO20PO70EO20) by controlling the molar ratio of tetramethoxysilane (TMOS) to 1,2-bis(trimethoxysilyl)ethane (BTME) in the initial mixture during the co-condensation process of silane precursors in acidic medium. Structural characterizations (X-ray diffraction, nitrogen sorption analysis, and transmission electron microscopy) show that all materials have ordered hexagonal Mesoporous structure with large pore diameter (7–9 nm). The existence of ethane and sulfonic acid groups in the material was verified by 29Si MAS and 13C CP MAS NMR and X-ray photoelectron spectroscopy (XPS). The Mesoporous solid acids can adsorb both water and hexane (the adsorption capacity for water and hexane is 240 and 600 mg/g, respectively) due to the existence of surface hydroxyl groups, propyl sulfonic acid group, and the ethane moiety. These Mesoporous solid acids are efficient catalysts for the dehydration of 1-butanol and the hydration of propylene oxide (PO).
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chiral Mesoporous Organosilicas with r binol integrated in the framework
Microporous and Mesoporous Materials, 2009Co-Authors: Lei Zhang, Jian Liu, Jie Yang, Peiyuan Wang, Qihua YangAbstract:Abstract Bifunctionalized chiral Mesoporous Organosilicas with both R -(+)-Binol and ethylene moieties integrated in the framework was synthesized by co-condensation of 1,2-bis(trimethoxysilyl)ethane (BTME) and ( R )-2,2′-dimethoxy-6,6′-di-[(2-trimethoxysilyl)-ethenyl]-1,1′-binaphthyl ( R -MMB) in acidic medium using P123 as template for the first time. With the molar fraction of R -MMB increasing from10 to 20% in the initial mixture, the mesostructure of the material changes from a well-ordered 2D hexagonal mesostructure to a worm-like structure. The materials have a pore diameter in the range of 4.8–5.2 nm with BET surface areas varying from 356 to 894 m 2 g −1 . The results of FT-IR, 13 C and 29 Si solid-state NMR shows the integration of the organic groups in the material though some Si–C bond cleavage was observed during the synthesis. The circular dichroism spectrum of the material dissolved in NaOH confirms that the chirality of R -(+)-Binol in the material remains unchanged compared with the molecular precursor. The hydroxyl groups of the R -(+)-Binol units were liberated by treatment of the material with BBr 3 . The resultant materials were used in Ti-promoted asymmetric addition of diethylzinc to benzaldehyde. High catalytic activity (99%) with moderate enantioselectivity (39.7%) was achieved, which also confirms that R -Binol was incorporated in the PMOs successfully.
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Mesoporous Organosilicas containing disulfide moiety synthesis and generation of sulfonic acid functionality through chemical transformation in the pore wall
Microporous and Mesoporous Materials, 2008Co-Authors: Jian Liu, Lei Zhang, Jie Yang, Qihua YangAbstract:Abstract Mesoporous Organosilicas with disulfide moiety bridged in the pore wall have been synthesized by co-condensation of bis[3-(triethoxysilyl)propyl]disulfide (BTPDS) and tetramethoxysilane (TMOS) in acetic acid/sodium acetate buffer solution (HAc–NaAc, pH 4.4), using nonionic surfactant P123 as the template. With the molar percent of BTPDS increasing, the mesostructure of the resultant material transforms from highly ordered 2-D hexagonal structure to cellular foam structure. The disulfide moiety could be transferred to sulfonic acid functionality by a simple post-oxidation method. The structural characterizations show that the mesostructure changes during the oxidation step especially for the materials with high content of disulfide moiety. In the esterification of aliphatic acid and ethanol, the oxidized materials show higher yield than the conventional heterogeneous solid acids such as zeolites and sulfonic acid resin. Comparisons of the structural properties and the catalytic results of the materials show that a large pore diameter and low surface hydrophilicity are required to obtain high catalytic activity.
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periodic Mesoporous Organosilicas with 1 4 diethylenebenzene in the Mesoporous wall synthesis characterization and bioadsorption properties
Journal of Physical Chemistry C, 2007Co-Authors: Jian Liu, Xin Shi, Jie Yang, Qihua YangAbstract:The 1,4-diethylenebenzene-bridged Mesoporous Organosilicas and bifunctional periodic Mesoporous Organosilicas with various amounts of 1,4-diethylenebenzene and ethane bridging groups in the mesopor...
Pascal Van Der Voort - One of the best experts on this subject based on the ideXlab platform.
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lanthanide grafted bipyridine periodic Mesoporous Organosilicas bpy pmos for physiological range and wide temperature range luminescence thermometry
ACS Applied Materials & Interfaces, 2020Co-Authors: Anna M Kaczmarek, Shinji Inagaki, Yoshifumi Maegawa, Anatolii Abalymov, Andre G Skirtach, Pascal Van Der VoortAbstract:2,2'-Bipyridine is the most widely used chelating ligand for developing metal complexes in coordination and supramolecular chemistry. Here, we present a series of three bipyridine periodic Mesoporous Organosilicas (BPy-PMOs) grafted with lanthanide β-diketonate complex for the purpose of obtaining thermochromic materials, which can be employed as ratiometric temperature sensors. Such thermometers are based on the ratio of two emission intensity peaks and are not affected by factors such as alignment or optoelectronic drift of the excitation source and detectors. Three thermometric systems are studied: Dy-Dy, Tb-Sm, and Tb-Eu with the first two showing very attractive performance. For the first two systems, some of the best reported to date relative sensitivities are observed. In the BPy-PMO@Dy(acac)3 system, it is very unusual that the 4I15/2→ 6H15/2 transition is already occupied at low temperature such as 200 K, which influences its thermometric behavior. The Tb-Sm shows excellent performance in the physiological range and when suspended in water. We have additionally confirmed that the BPy-PMO hybrid materials lack toxicity to human cells, proving them very promising candidates for biomedical thermometric applications.
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functionalized periodic Mesoporous Organosilicas from metal free catalysis to sensing
Journal of Materials Chemistry, 2019Co-Authors: Laurens Bourda, Himanshu Sekhar Jena, Rik Van Deun, Anna M Kaczmarek, Pascal Van Der VoortAbstract:In this work a widely usable post-modification route for periodic Mesoporous Organosilicas (PMOs) was developed. Using the developed method, two diverse ligands, picolinic acid (Pic) and 4,4′,4′′,4′′′-porphyrin-5,10,15,20-tetrayltetrabenzoic acid (Porph), were successfully covalently coupled onto the PMO material and well-characterized. Both obtained materials show high BET surface areas (565 m2 g−1 for Pic@PMO, 483 m2 g−1 for Porph@PMO and 548 m2 g−1 for the unmodified PMO) and pore sizes (5.1 nm). The materials were subsequently tested for their catalytic activity in the cycloaddition of epoxide and CO2, a frequently studied carbon capture and utilization reaction. Interestingly, both materials showed very good reactivity (with conversions of up to 90%) as metal free heterogeneous catalysts and proved to be perfectly stable in recyclability and aging tests. Moreover, by (co-)grafting Eu3+ and Tb3+ ions onto Pic@PMO and Yb3+ ions onto Porph@PMO a strong emission was observed in the visible and near-infrared (NIR) range, respectively. Eu,Tb@Pic@PMO showed potential for use as a temperature sensor in the physiological range (a maximum Sr value of 2.11 %K−1 was obtained at 273 K), while Yb@Porph@PMO could efficiently be excited within the human tissue penetrating window showing characteristic Yb3+ luminescence (with decay times of around 10 μs). These findings prove that simple modifications of this PMO can provide smart materials for very diverse applications.
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periodic Mesoporous Organosilicas as porous matrix for heterogeneous lyophobic systems
Microporous and Mesoporous Materials, 2018Co-Authors: Andrey Ryzhikov, Pascal Van Der Voort, Els De Canck, Jean T Daou, Habiba Noualia, Joel Patarin, Judith Ouwehand, Sander Clerick, Johan A MartensAbstract:Periodic Mesoporous Organosilicas (PMO) have been studied for the first time as a porous matrix for heterogeneous lyophobic systems (HLS) for absorption and storage of mechanical energy by high pressure intrusion extrusion of electrolyte solutions. It has been shown that the intrusion of LiCl aqueous solutions in ethane bridged PMO material is irreversible that corresponds to a bumper behavior. The intrusion pressure increases strongly with the salt concentration - from 13 MPa for 5 M LiCl aqueous solution to 37 MPa for 20 M one. Such a pressure rise of 2.8 times is the highest observed for HIS based on Mesoporous materials. Due to high intruded volume (0.63-0.72 mL/g) specific absorbed energy achieves 27 J/g, which is close to the best values ever obtained for HLS based on zeosils and Mesoporous silica. The characterization shows that after the intrusion extrusion experiments the ordered pore arrangement largely stays intact, but a slight increase of the mesopore volume is observed.
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periodic Mesoporous Organosilicas functionalized with a wide variety of amines for co2 adsorption
Physical Chemistry Chemical Physics, 2013Co-Authors: Els De Canck, Isabelle Ascoop, Abdelhamid Sayari, Pascal Van Der VoortAbstract:The adsorption of CO2 on amine modified periodic Mesoporous Organosilicas (PMOs) has been investigated. An ethenylene-bridged PMO is modified with a wide range of diamines and polyamines. A variety of dangling N-containing functionalities, i.e., diaminobutane, diaminohexane, diaminododecane, diethylenetriamine and tetraethylenepentamine, as nucleophiles in a substitution reaction is used. The CO2 adsorption capacity of these materials is probed and compared with amine functionalized SBA-15 material, in an effort to reach the maximal CO2/N ratio of 0.5 when using dry conditions in a chemisorption process. The materials showed good CO2 adsorption behaviour and this maximum amine efficiency value has been approximated by the PMO material modified with diaminododecane.
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Periodic Mesoporous Organosilicas : from simple to complex bridges : a comprehensive overview of functions, morphologies and applications
Chemical Society reviews, 2013Co-Authors: Pascal Van Der Voort, Dolores Esquivel, Els De Canck, Frederik Goethals, Isabel Van Driessche, Francisco J. Romero-salgueroAbstract:Periodic Mesoporous Organosilicas (PMOs) were developed in 1999 and are basically ordered templated Mesoporous Organosilicas, prepared by the combination of a surfactant as template and a silsesquioxane as the organosilica precursor. They were one of the first examples of the so-called “hybrid” organic/inorganic materials. In the years that followed, an amazing variety of functional groups, morphologies and applications has been developed. Some of these high-end applications, like low-k buffer layers in microelectronics, chiral catalysts, chromatographic supports, selective adsorbents and light-harvesting devices, have clearly shown their potential. In this review, we will give a comprehensive overview of all these different functionalities and applications that have been created for Periodic Mesoporous Organosilicas.