Generalised syntheses of ordered mesoporous oxides: the atrane route

Cabrera, Saúl; Haskouri, Jamal El; Guillem, Carmen; Latorre, Julio; Beltrán-Porter, Daniel; Marcos, M. Dolores; Amorós, Pedro

doi:10.1016/s1293-2558(00)00152-7

Cited by 222 publications

(206 citation statements)

References 43 publications

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“…9 The small mesoporous system is generated with the help of the template effect of the surfactant (it very likely might be modulated by changing the length of its chains). The large pores (in the border between the meso-and macro-pore domains) are generated as the nucleation and growth of the primary mesoporous nanoparticles proceeds.…”

Section: T H I S J O U R N a L I S © T H E R O Y A L S O C I E T Y Omentioning

confidence: 99%

“…9 In fact, TEAH3 derivatives have been also used as hydrolytic precursors in the synthesis of mesoporous silicas through nonsurfactant-assisted procedures. 10 In a typical synthesis leading to the UVM-7 pure silica, 4.23 g of CTABr were added at 60 °C to a solution of TEAH3 (23 ml) containing 0.045 mol of a silatrane derivative of TEAH3 (e.g.…”

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confidence: 99%

“…This mixture was aged at room temperature for 2 h. The resulting powder was collected by filtration, washed with water and ethanol, and airdried. To prepare the final porous material, the as-synthesised solid was calcined at 500 °C for 5 h. Heteroelement incorporation is achieved by simply adding variable amounts of the respective metal-atrane complexes 9 to the silatrane containing solution, and following then the same general procedure. Table 1 summarizes the main synthesis variables and physical data.…”

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confidence: 99%

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Silica-based powders and monoliths with bimodal pore systemsElectronic supplementary information (ESI) available: UV–Vis spectrum of sample 3. See http://www.rsc.org/suppdata/cc/b1/b110883b/

et al. 2002

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Porous pure and doped silicas with pore sizes at two length scales (meso/macroporous) have been prepared and shaped both as powders and monoliths through a one-pot surfactant assisted procedure by using a simple template agent and starting from atrane complexes as inorganic precursors.High surface porous materials showing tailor-made pore sizes and shapes are especially interesting in a variety of applications where molecular recognition is needed. 1 The discovery of the M41S family of mesoporous silicas was a breakthrough finding in this field by opening a new way towards ordered uniform mesoporous systems, which in turn implied an opportunity for expanding the available pore sizes typical of zeolites. 2 Once the preparation of MCM-41 related solids began to be controlled, a new key objective was to achieve the incorporation of different elements to the silica materials to modulate their catalytic properties. 3 Among the many problems associated to this goal, those related with accessibility to the active sites have meant, in some cases, non-attainment of the catalytic performances which could be a priori expected on the basis of the intimate nature of a given material. Several strategies have been developed to overcome such a limitation. Thus, the site accessibility (and, therefore, the catalytic response) can be enhanced through insertion of active elements in mesoporous solids having relatively small particle sizes (HMS solids) 4 or displaying interconnected 3-D channel systems (MCM-48). 5 In some cases, this goal can be simply achieved by expansion of the pore sizes. 6 Recently, it has been reported on the preparation of bimodal (meso-macro or micro-macro) porous materials having enhanced site accessibility. 7 In this last case, the synthesis strategy includes the use of additional templates (besides the proper surfactant), such as latex spheres and microemulsions. This is a polished successful approach.However, besides its apparent singularity, it necessarily implies previous somewhat cumbersome processes of preparation and stabilisation of the large-scale template.We report here on a new direct and reproducible one-pot surfactant-assisted procedure that has allowed us to prepare silica-based materials, both as powders and monoliths (denoted UVM-7 and M-UVM-7), having bimodal pore systems (mesolarge mesoporous or meso-macroporous) and containing a diversity of dopant elements (M = Al, Ti, V, Zr). 8 Modulation of pore sizes depends on both the surfactant (small pores) and the procedural (synthesis and ageing) conditions (large pores).The procedure is based on the use of a simple structural directing agent (CTABr = cetyltrimethylammonium bromide) and a complexing polyalcohol (2,2A,2B-nitrilotriethanol, TEAH3) able to adequately regulate the rates of the hydrolysis and condensation processes involving the different inorganic components (or heteroelements) of the final material. 9 In fact, TEAH3 derivatives have been also used as hydrolytic precursors in the synthesis of mesoporous silicas through nonsurfactan...

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Section: T H I S J O U R N a L I S © T H E R O Y A L S O C I E T Y Omentioning

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Silica-based powders and monoliths with bimodal pore systemsElectronic supplementary information (ESI) available: UV–Vis spectrum of sample 3. See http://www.rsc.org/suppdata/cc/b1/b110883b/

et al. 2002

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“…As stated above in classical self-immolative chemistry a single activation event usually leads to the release of a single group whereas the design of self-immolative systems for the delivery of multiple groups is usually difficult and requires the preparation of rather complex challenging molecules from a synthesis point of view. [15] In this scenario, the anchoring as cap of a simple molecule such as 1 in MSNs allows to design systems in which a single activation in 1 induced the release of a large number of cargo molecules (in our case a dye). In fact, one reported advantage of gated materials is the existence of amplification features.…”

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Self‐Immolative Linkers as Caps for the Design of Gated Silica Mesoporous Supports

Juárez

Añón

Giménez

et al. 2016

Chemistry A European J

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Synthesis, characterization and controlled release behavior of a new hybrid material based on silica mesoporous nanoparticles caped with a self-immolative gate is reported.There is a significant interest in the development of methodologies of controlled release for a diverse range of applications. [1] For this reason, a large diversity of drug nanocarriers having different size, structure and surface properties, such as liposomes and polymeric or inorganic nanoparticles, have been developed over the last decades. [2] Among these, mesoporous silica nanoparticles (MSNs) have attracted great attention in recent years due to their unique features such as stability, biocompatibility, large load capacity and the possibility of easy functionalizing their surface to obtain targeting and drug release systems. [3] In this scenario, an appealing concept when using MSNs is the possibility to functionalize the external surface with gated ensembles. The development of gated systems able to retain the payload yet releasing it upon the presence of a predefined stimulus has been proved to be an excellent approach to develop advanced nanodevices for controlled delivery applications. [4] In fact, through decoration of the mesoporous material with a wide collection of organic and biological entities or inorganic capping agents, researchers have prepared recently gated MSNs that can be triggered by target chemical (such as selected anions, cations neutral molecules, redox-active molecules, pH changes and biomolecules), physical (such as light, temperature, magnetic fields or ultrasounds) and biochemical (such as enzymes, antibodies, or DNA) stimuli. [5] From a different point of view, self-immolative molecules are covalent aggregates that, upon application of an external trigger, initiate a disassembly reaction, through a cascade of electronic elimination processes, leading ultimately to the release of its building blocks. [6] This chemical phenomenon is usually driven by a cooperative increase in entropy coupled with the irreversible formation of thermodynamically stable products. These molecules have been extensively used in several applications including the design of prodrugs, [7] sensors [8] and drug delivery systems. [9] Self-immolative processes can commonly be found for polysubstituted, electron-rich aromatic species containing an electron-donating substituent in conjugation (ortho or para) with a suitable leaving group located in a benzylic position. [10] In classical self-immolative linkers a single activation event leads to the release of a single group. This release can be described as non-amplified. In contrast the evolution of this technology has resulted in recent years in the design of self-immolative systems in which a single activation event leads to the delivery of multiple groups. This has been described as amplified release. [11] Scheme 1. (a) Schematic representation of the prepared gated nanoparticles S1, (b) synthesis of self-immolative molecular gate 1 and the cascade electronic eliminatio...

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“…To further expand the pore size of the nanoparticles N,N-dimethylhexadecylamine (DMHA) and 1,3,5-trimethylbenzene (TMB) as swelling agents were used to synthesize pore-expanded materials. [44,45] Once the final templated material is prepared, CTAB was removed from the silicate lattice by calcination or by solvent extration. Calcination is the burning out of the template under conditions which do not greatly affect the integrity of silicate structure.…”

Section: Scheme 12mentioning

confidence: 99%

Nanotechnology and supramolecular chemistry in controlled release and molecular recognition proceses for biomedical applications"

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CERTIFY:That the work "Nanotechnology and supramolecular chemistry in controlled release and molecular recognition processes for biomedical applications" has been AgradecimientosComo en cualquier carrera de fondo, lo importante de llegar a meta es todo lo que aprendes en el camino. Llegados a este punto, donde me encuentro en la recta final para cruzar la línea de meta, es importante echar la vista atrás y agradecer a todas esas personas que dia a dia te ayudan a continuar caminando, a no detenerte y a afrontar los distintos obstáculos que te encuentras.En primer lugar, agradecer a mi director, el Profesor Ramón Matinez Mañez por darme la oportunidad de realizar la tesis doctoral en su grupo de investigación. Gracias por confiar en mi desde el primer momento, siempre recordaré la entrevista en la que me comentabas que realizaría ensayos en células porque la doctora que se ocupa de ellos se marchaba en breve y yo te contesté, con total sinceridad, que no tenía ningún conocimiento de cultivos celulares pero que aprendería sin problemas (en ese momento en mi cabeza pensaba : "y yo que estudié dibujo técnico en lugar de biología en Bachillerato…mare meua!"). Gracias por darme la oportunidad de crecer "químicamente", por la libertad e independencia que me has dado durante este periodo ya que gracias a ello he aprendido a superar los obstáculos y problemas que surgen, a "buscarme las castañas".Como no, agradecer a Félix Sancenón por ser mi segundo director, por ser el filtro de todos los papers, la persona que siempre está disponible para responder tus dudas experimentales, para corregirte lo que necesites y siempre con una eficiencia difícil de mejorar. Considero que todo el trabajo realizado ha sido posible gracias a tu ayuda y a tus consejos y positividad. Haces las cosas mucho más fáciles, al principio, durante y ahora en la recta final, ayudándome con todos los trámites de la tesis.También agradecer la ayuda prestada a Loles, Jose Vicente, Jose Ramón Murguía y Luis Villaescusa (y sus clases y conversaciones en la sala del Rayos X). AgradecimientosGracias a Quique y Eva, por todos los trámites que nos facilitais, por solucionar los lios de compras en los que nos metemos a veces y por vuestra eficiencia.Muchisimas gracias a Mar Orzaez y Enrique Pérez Payá, por todo lo que me habéis enseñado y por la paciencia que tuvisteis conmigo en los inicios de la tesis.Gracias por aceptarme en vuestro laboratorio y hacer que fuera una más en él.Gracias a Maria José Alcaraz y a su laboratorio, en especial a Carmen Terencio.Gracias por lo que me has enseñado, por como me has tratado, de tú a tú y por la confianza que has puesto en mi. Gracias a Reynaldo por las colaboraciones que hemos realizado y el trabajo en equipo que tan bien organiza.Inifinitas gracias a Eduardo Ruiz, por recibirme con los brazos abiertos en su laboratorio de Dublin. "Una actitud positiva causa una reacción en cadena de pensamientos, sucesos y resultados positivos". Esta frase te define a la perfección.Durante el tiempo que estuvimos trabajando juntos des...

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Generalised syntheses of ordered mesoporous oxides: the atrane route

Cited by 222 publications

References 43 publications

Silica-based powders and monoliths with bimodal pore systemsElectronic supplementary information (ESI) available: UV–Vis spectrum of sample 3. See http://www.rsc.org/suppdata/cc/b1/b110883b/

Silica-based powders and monoliths with bimodal pore systemsElectronic supplementary information (ESI) available: UV–Vis spectrum of sample 3. See http://www.rsc.org/suppdata/cc/b1/b110883b/

Self‐Immolative Linkers as Caps for the Design of Gated Silica Mesoporous Supports

Nanotechnology and supramolecular chemistry in controlled release and molecular recognition proceses for biomedical applications"

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