Synthesis and catalytic activity of a chiral periodic mesoporous organosilica (ChiMO)

Baleizão, Carlos; Gigante, Bárbara; Das, Debasish; Álvaro, Mercedes; Garcı́a, Hermenegildo; Corma, Avelino

doi:10.1039/b304814d

Cited by 238 publications

(256 citation statements)

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“…For example, Alvaro et al 108 used chiral binaphthyl precursors with trialkoxysilane TEOS for the preparation of optically-active porous material that linearly rotates polarized light. Corma et al 109 used chiral trialkoxysilane grafting onto mesoporous silica materials, forming a whole range of chiral catalysts. In addition, there were reports on antibody-based bionanotube membranes for enantiomeric drug separation.…”

Section: Template-based Imprinting Approachmentioning

confidence: 99%

Biomimetic Polymers for Chiral Resolution and Antifreeze Applications

Medina¹,

Mastai²

2011

On Biomimetics

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Section: Template-based Imprinting Approachmentioning

confidence: 99%

Biomimetic Polymers for Chiral Resolution and Antifreeze Applications

Medina¹,

Mastai²

2011

On Biomimetics

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“…1 They are prepared via the direct condensation of bridged organosilanes, most commonly of the type (RO) 3 Si-R 0 -Si(OR) 3 , in the presence of a structure directing agent. This way nanocomposites with a high organic content can be obtained while preserving the pore ordering and uniformity.…”

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Ethenylene-bridged periodic mesoporous organosilicas with ultra-large mesopores

et al. 2009

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E-configured ethenylene-bridged periodic mesoporous organosilicas with ultra-large mesopores and unprecedented pore volumes have been developed for the first time.Periodic mesoporous organosilicas (PMOs) are a relatively novel group of organic-inorganic hybrid materials in which the organic groups are not located in the pores, but rather are an intrinsic part of the pore walls. 1 They are prepared via the direct condensation of bridged organosilanes, most commonly of the type (RO) 3 Si-R 0 -Si(OR) 3 , in the presence of a structure directing agent. This way nanocomposites with a high organic content can be obtained while preserving the pore ordering and uniformity. Ethenylene-bridged PMOs are especially interesting as they are easily modified by means of olefin chemistry. 2 Due to their structural rigidity and controllable hydrophobic character, PMOs are of great interest for applications in catalysis, 3 environmental technology 4,5 and chromatography. 6 However, the applicability of PMOs is often limited by their pore sizes, which typically range between 2 and 8 nm. In some applications, such as in biocatalysis or controlled drug release, larger mesopores are required to allow the diffusion, adsorption or immobilization of large biomolecules such as enzymes, proteins or drugs. To date, the synthesis of ethenylene-bridged PMOs with mesopores larger than 15 nm has not been reported, so with this goal in mind, we probed the possibility of adapting pluronic P123 as a template, in combination with 1,3,5-trimethylbenzene (TMB) as a sweller.Recently we reported a novel synthesis of diastereoisomeric, hexagonally ordered ethenylene-bridged PMOs. 7,8 Here we report on a new and easy method to develop ultra-large pore isomeric PMOs with unprecedented pore volumes consisting of various pore systems, including foam-like pore structures with uniformly sized mesopores, 3D stacked spherical pores and nodular strings, i.e. cylinders built from linearly connected spheres. In a typical synthesis, 1.0 g of P123 was diluted in a solution containing 48.7 ml of H 2 O, 1.2 ml of n-butanol and 2.1 ml of concentrated HCl. The mixture was stirred at room temperature until P123 was fully dissolved, after which a varying amount of TMB was added. This solution was stirred for 0.5 h, after which 1.86 ml of the homemade E-1,2-bis-(triethoxysilyl)ethene was added. 7 Finally, the mixture was stirred for 3 h at 35 1C and aged for 24 h in an autoclave at 100 1C. The PMO was filtrated and the template removed by means of extraction with acetone. Following this procedure a series of 4 PMOs were synthesized by varying the amount of TMB, while keeping all other parameters constant. The results are given in Table 1.By varying the amount of TMB, the pore size can be engineered from approximately 8.1 to 28.3 nm. Moreover, by increasing the amount of TMB, PMOs with extremely high pore volumes can be attained. When employing 7.76 mmol of TMB, a PMO with a pore diameter of 28.3 nm and a total pore volume of 2.25 cm 3 g À1 was acquired, which, to the best ...

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“…1a). Similarly, the 13 C NMR signal characteristic of the CC bond (d = 145 ppm) disappears (spectrum not shown). In the 11 B NMR spectrum, only one broad signal at d = -1.4 ppm is found, which is markedly different from the reducing agent catecholborane (d = 5.9 ppm).…”

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confidence: 99%

“…[13] The previous work described the synthesis of a mesoporous material by the cocondensation route involving a bis-alkoxysilane with a chiral vanadyl salen complex as the bridging organic ligand along with tetraethoxysilane (TEOS). [13] The maximum amount of the chiral bis-alkoxysilane used was 15 %, and the new sol-gel precursor contains a potentially labile thioether group. A cocondensation process was probably necessary in order to incorporate the large and hydrophobic salen complex into the mesoporous framework.…”

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confidence: 99%

“…In order to overcome the increased hydrophobicity, the authors used ethanol as a co-solvent. [13] The key to obtaining a PMO material from a single precursor is therefore the synthesis of a bis-alkoxysilane with a chiral bridging organic group that is as small as possible, while also being potentially hydrophilic. Fairly well-ordered PMO materials have been prepared using (R′O) 3 Si-CH 2 CH 2 -Si(OR′) 3 as a precursor.…”

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Preparation of a Periodically Ordered Mesoporous Organosilica Material Using Chiral Building Blocks

Polarz

Kuschel

2006

Advanced Materials

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Chiral bis‐alkoxysilanes are used as building blocks for the synthesis of new periodically ordered mesoporous organosilica materials (see figure). A bis‐alkoxysilane molecule with a chiral group as a bridging organic ligand is prepared via enantioselective organometallic catalysis using a ruthenium catalyst with 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthalene as a ligand. The synergistic co‐assembly is then used to prepare a high‐surface‐area mesoporous material with an average pore size of about 3 nm.

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Synthesis and catalytic activity of a chiral periodic mesoporous organosilica (ChiMO)

Cited by 238 publications

References 10 publications

Biomimetic Polymers for Chiral Resolution and Antifreeze Applications

Biomimetic Polymers for Chiral Resolution and Antifreeze Applications

Ethenylene-bridged periodic mesoporous organosilicas with ultra-large mesopores

Preparation of a Periodically Ordered Mesoporous Organosilica Material Using Chiral Building Blocks

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