Dynamic Microcrystal Assembly by Nitroxide Exchange Reactions

Schulte, Birte; Tsotsalas, Manuel; Becker, Maike; Studer, Armido; Cola, Luisa De

doi:10.1002/anie.201002851

Cited by 81 publications

(60 citation statements)

References 51 publications

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“…[17] In this study,weexamine the impact of alkali distribution in amorphous precursors of zeolite L( LTL), ao ne-dimensional large pore zeolite with cylindrical morphology (Figure S1 in the Supporting Information). Zeolite Li su sed commercially as ac atalyst and is ap romising material for applications in photonics [18] and drug delivery. [19] Unlike the vast majority of zeolite frameworks,z eolite Li sp repared without organics using potassium as the sole structuredirecting agent (SDA).…”

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confidence: 99%

Ultrasmall Zeolite L Crystals Prepared from Highly Interdispersed Alkali‐Silicate Precursors

Linares

Sutjianto

et al. 2018

Angew Chem Int Ed

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The preparation of nanosized zeolites is critical for applications where mass-transport limitations within microporous networks hinder their performance. Often the ability to generate ultrasmall zeolite crystals is dependent upon the use of expensive organics with limited commercial relevance. Herein, we report the generation of zeolite L crystals with uniform sizes less than 30 nm using a facile, organic-free method. Time-resolved analysis of precursor assembly and evolution during nonclassical crystallization highlights key differences among silicon sources. Our findings reveal that a homogenous dispersion of potassium ions throughout silicate precursors leads to the formation of a metastable nonporous phase, which undergoes an intercrystalline transformation to zeolite L. The generation of highly interdispersed alkali-silicate precursors is seemingly critical to enhancing the rate of nucleation and facilitating the formation of ultrasmall crystal.

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confidence: 99%

Ultrasmall Zeolite L Crystals Prepared from Highly Interdispersed Alkali‐Silicate Precursors

Linares

Sutjianto

et al. 2018

Angew Chem Int Ed

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“…The incorporation of alkoxyamine units in simple macromolecular architectures enables to prepare through nitroxide exchange reactions more sophisticated architectures such as star polymers,63,64 polymer hybrids,65,66 macrocycles,67 and polymer brushes68 and to control crystal assembly 69. In the same manner, linear polymers containing several alkoxyamine functions have appeared as versatile polyinitiators43 to synthesize multiblock copolymers.…”

Section: Discussionmentioning

confidence: 99%

A styryl tipno‐based nitroxide as efficient mediator for the synthesis of multiblock polystyrenes and well‐grafted polymers

Souchal

Roels

Hémery

et al. 2012

J. Polym. Sci. A Polym. Chem.

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The chloromagnesium exchange of 4‐chlorostyrene provides an easy access to a new versatile polymerizable 2,2,5‐trimethyl‐4‐phenyl‐3‐azahexane‐3‐nitroxide (TIPNO)‐based nitroxide. Indeed, first, its alkoxyamine based on the α‐methyl benzyl radical fragment efficiently mediates the polymerization of styrene (respectively n‐butyl acrylate) to yield branched polystyrene [respectively poly(n‐butyl acrylate)] with alkoxyamine function as branch point and well‐defined branches. Second, the self‐condensing of this polymerizable nitroxide by manganese coupling affords a mixture of oligomeric linear polyalkoxyamines. Polymerization of styrene mediated with these polyalkoxyamines gives multiblock polystyrenes with alkoxyamine group as linker between polystyrene blocks and exhibits the following features: the synthesis of the polystyrene blocks is controlled as their average molecular weight Mn(block) increases linearly with conversion and their average dispersity Mw/Mn(block) decreases with it. At a given temperature, the molecular weight and the dispersity of the polyalkoxyamines weakly impact Mn(block) and Mw/Mn(block). In contrast, the molecular weight of the multiblock polystyrene increases linearly with conversion until reaching a constant value. The number of block is independent of the molecular weight of the polyalkoxyamines. These unusual results can be explained by the fact that during polymerization, mediating TIPNO‐based polymeric nitroxides with different lengths are generated and are exchanged. Finally the dispersity of the multiblock polystyrene is quite broad and lies between 1.7 and 2.8. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

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“…Experience, however,tells adifferent story.T he diversity of guest-ZL composites exhibiting al arge range of properties is impressive. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] It emerges from the fact that the variety of molecules that fit into these narrow channels is large, and that confinement favors the formation of sandwich-types tructures (Scheme 1), includingt he possibility for rational stopcock modification. [1,5,11,[15][16][17] The size and morphology of the ZL host crystals can be tuned from about 30 nm to severalm icrometers,a nd from elongatedt od iskshaped.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular Organization of Dye Molecules in Zeolite L Channels: Synthesis, Properties, and Composite Materials

Cao

Khorev

Devaux

et al. 2016

Chemistry A European J

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Sequential insertion of different dyes into the 1D channels of zeolite L (ZL) leads to supramolecular sandwich structures and allows the formation of sophisticated antenna composites for light harvesting, transport, and trapping. The synthesis and properties of dye molecules, host materials, composites, and composites embedded in polymer matrices, including two-and three-color antenna systems, are described. Perylene diimide (PDI) dyes are an important class of chromophores and are of great interest for the synthesis of artificial antenna systems. They are especially well suited to advancing our understanding of the structure-transport relationship in ZL because their core fits tightly through the 12-ring channel opening. The substituents at both ends of the PDIs can be varied to a large extent without influencing their electronic absorption and fluorescence spectra. The intercalation/insertion of 17 PDIs, 2 terrylenes, and 1 quaterrylene into ZL are compared and their interactions with the inner surface of the ZL nanochannels discussed. ZL crystals of about 500 nm in size have been used because they meet the criteria that must be respected for the preparation of antenna composites for light harvesting, transport, and trapping. The photostability of dyes is considerably improved by inserting them into the ZL channels because the guests are protected by being confined. Plugging the channel entrances, so that the guests cannot escape into the environment is a prerequisite for achieving long-term stability of composites embedded in an organic matrix. Successful methods to achieve this goal are described. Finally, the embedding of dye-ZL composites in polymer matrices, while maintaining optical transparency, is reported. These results facilitate the rational design of advanced dye-zeolite composite materials and provide powerful tools for further developing and understanding artificial antenna systems, which are among the most fascinating subjects of current photochemistry and photophysics.

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Dynamic Microcrystal Assembly by Nitroxide Exchange Reactions

Cited by 81 publications

References 51 publications

Ultrasmall Zeolite L Crystals Prepared from Highly Interdispersed Alkali‐Silicate Precursors

Ultrasmall Zeolite L Crystals Prepared from Highly Interdispersed Alkali‐Silicate Precursors

A styryl tipno‐based nitroxide as efficient mediator for the synthesis of multiblock polystyrenes and well‐grafted polymers

Supramolecular Organization of Dye Molecules in Zeolite L Channels: Synthesis, Properties, and Composite Materials

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