Recyclable organocatalysts based on hybrid silicas

Ferré, Meritxell; Pleixats, Roser; Man, Michel Wong Chi; Cattoën, Xavier

doi:10.1039/c5gc02579f

Cited by 121 publications

(85 citation statements)

References 219 publications

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“…[37] Silica NPs are slowly degraded in water by dissolution into biocompatible and bioadsorbed silicic acid products, [38] and silica NPs are renally excreted. [39][40][41] The unique properties of MSN and silica hybrid NPs have been implemented in catalysis, [37,42] separation, [43][44][45] bio-imaging, [33,[46][47][48] and in cargo delivery applications, [34][35][36][37][49][50][51] to name a few. Large-pore silica and silica hybrid NPs have also been designed for biomedical applications.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Biodegradable Magnetic Silica@Iron Oxide Nanovectors with Ultra-Large Mesopores for High Protein Loading, Magnetothermal Release, and Delivery

Omar

Croissant

Alamoudi

et al. 2017

Journal of Controlled Release

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Abstract:The delivery of large cargos of diameter above 15 nm for biomedical applications has proved challenging since it requires biocompatible, stably-loaded, and biodegradable nanomaterials. In this study, we describe the design of biodegradable silica-iron oxide hybrid nanovectors with large mesopores for large protein delivery in cancer cells. The mesopores of the nanomaterials spanned from 20 to 60 nm in diameter and post-functionalization allowed the electrostatic immobilization of large proteins (e.g. mTFP-Ferritin, ~534 kDa). Half of the content of the nanovectors was based with iron oxide nanophases which allowed the rapid biodegradation of the carrier in fetal bovine serum and a magnetic responsiveness. The nanovectors released large protein cargos in aqueous solution under acidic pH or magnetic stimuli. The delivery of large proteins was then autonomously achieved in cancer cells via the silica-iron oxide nanovectors, which is thus a promising for biomedical applications.

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Section: Accepted M Manuscriptmentioning

confidence: 99%

Biodegradable Magnetic Silica@Iron Oxide Nanovectors with Ultra-Large Mesopores for High Protein Loading, Magnetothermal Release, and Delivery

Omar

Croissant

Alamoudi

et al. 2017

Journal of Controlled Release

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“…The immobilization of homogeneous catalysts on various insoluble supports such as a siliceous material makes the immobilized catalyst insoluble in the reaction solution, providing great advantages for the easy separation of the catalyst from the reaction mixture, the fast isolation of the reaction products, and catalyst recovery and recycling by simple filtration . The immobilization of homogeneous catalysts also allows insoluble catalysts, which would otherwise be aggregated, to be well dispersed in the reaction medium such as water, resulting in the significant enhancement in the catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

2018

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In the homogenous phase, redox catalysts are often deactivated by bimolecular reactions. For example, the charge‐separated state of photoredox catalysts decayed via bimolecular back electron transfer reactions between the charge‐separated molecules to decrease the lifetimes of the catalytically active species. When photoredox catalysts are immobilized on solid supports, the lifetime of the charge‐separated state was remarkably elongated to enhance the photocatalytic activity. Immobilization of photoredox catalysts on electrodes is required for photocurrent generation, leading to development of solar cells. Metal‐oxygen intermediates, which are active for oxidation of various substrates including water oxidation, are also deactivated via bimolecular reactions to produce inactive forms such as dinuclear metal bis‐μ‐oxo complexes. Immobilization of metal complex catalysts on solid supports prohibits the bimolecular deactivation, enhancing the catalytic activity and stability. This Review focuses on recent development of immobilization of both organic and inorganic molecular catalysts on various supports for enhancement of the catalytic activity, selectivity and stability in thermal and photoinduced redox reactions.

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“…Two different monosilylated proline sulphonamide precursors 1 and 2 (Schemes 1 and 2) were envisaged for the preparation of sol‐gel derived organocatalysts, which differ in the derivatization site on the catalytic moiety, and also in the nature and length of the linker. These structural features can exert an influence on the selectivity which will be discussed later …”

Section: Resultsmentioning

confidence: 99%

“…Despite the mentioned sustainable features of organocatalysis, the preparation of more complex organic catalysts may involve several steps, the reactions often require high catalyst loadings (up to 30 mol%) and the chromatographic purification of products becomes tedious. A straightforward step to ensure low environmental impact and to facilitate an easy separation, recovery and recycling is to tether organocatalysts on solid organic or inorganic polymeric supports in order to benefit from the usual advantages of heterogeneous catalysis . The formation of hybrid silica materials is attractive as a means to achieve supported catalysts, as these materials combine the advantages of a silica matrix (high surface area, thermal and mechanical stability and presumed chemical inertness) with the properties of the organic moiety .…”

Section: Introductionmentioning

confidence: 99%

Recyclable Silica‐Supported Proline Sulphonamide Organocatalysts for Asymmetric Direct Aldol Reaction.

et al. 2016

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We describe the preparation of several organosilicas based on proline sulphonamide scaffolds from two chiral monosilylated precursors following sol‐gel and grafting procedures. The materials were characterised by using 29Si solid‐state NMR spectroscopy, N2 sorption measurements, powder X‐ray diffractogram (p‐XRD) and elemental analysis. The catalytic performances and reusability of these hybrid silica materials have been evaluated in direct intermolecular asymmetric aldol reactions between ketones and aromatic aldehydes and in a Robinson annulation using simple and green conditions (water, room temperature). Good conversions and recyclability, and from moderate to good diastereo‐ and enantioselectivities have been achieved. The characteristics of the matrix, and structural features such as the nature and length of the linker, and the derivatisation site on the catalytic organic moiety have an influence on the activity and selectivity of the silica‐supported organocatalysts.

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Recyclable organocatalysts based on hybrid silicas

Abstract: International audienc

Cited by 121 publications

References 219 publications

Biodegradable Magnetic Silica@Iron Oxide Nanovectors with Ultra-Large Mesopores for High Protein Loading, Magnetothermal Release, and Delivery

Biodegradable Magnetic Silica@Iron Oxide Nanovectors with Ultra-Large Mesopores for High Protein Loading, Magnetothermal Release, and Delivery

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

Recyclable Silica‐Supported Proline Sulphonamide Organocatalysts for Asymmetric Direct Aldol Reaction.

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