Polyferrocenylsilan‐basierte Polymersysteme

Bellas, Vasilios; Rehahn, Matthias

doi:10.1002/ange.200604420

Cited by 79 publications

(30 citation statements)

References 304 publications

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“…[24,59] With the aim of exploiting the sensitivity of PFDMS towards acids, which leads to cleavage of the main chain, we incorporated a photoacid generator (PAG), 2-(4-methoxystyryl)-4,6-bis-A C H T U N G T R E N N U N G (trichloromethyl)-1,3,5-triazine, by dissolution of both the star-block copolymer and the PAG in THF (mass ratio 1:1) followed by subsequent addition of EtOH (Figure 8). During vesicle formation, a certain amount of PAG should be trapped inside the capsules.…”

Section: Resultsmentioning

confidence: 97%

“…The properties of PFS homopolymers depend strongly on the substituents present at silicon: Symmetrically substituted materials are, in general, semicrystalline [24,44,45] whereas PFSs with two different substituents are amorphous. [46] The polymerization of the organometallic monomer was carried out for 72 h and, after two-fold reprecipitation of the resulting orange materials to remove any unreacted PEO star macroinitiator, a four-arm star-block copolymer with a moderate PDI was obtained.…”

Section: Resultsmentioning

confidence: 99%

“…[15,16] In recent years several groups have reported on self-assembly phenomena with crystalline-coil block copolymers in which solvent quality and temperature play important roles. [17][18][19][20][21][22][23][24] We have established that where the core of a micelle is crystalline, epitaxial growth processes can be exploited to create a variety of well-defined supramolecular structures. For example, polyferrocenylsilane (PFS)-based systems with a crystalline PFS core allow the formation of monodisperse cylinders of controlled length, block co-micelles, and hierarchical architectures with spatially defined functionality by crystallization-driven living self-assembly.…”

Section: Introductionmentioning

confidence: 99%

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Responsive Vesicles from the Self‐Assembly of Crystalline‐Coil Polyferrocenylsilane‐block‐Poly(ethylene Oxide) Star‐Block Copolymers

Schacher¹,

Elbert²,

Patra³

et al. 2011

Chemistry A European J

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We demonstrate the synthesis and characterization of star-shaped crystalline-coil block copolymers with four arms consisting of an inner block of poly(ethylene oxide) and an outer semicrystalline compartment of poly(ferrocenyldimethylsilane), [PEO(50) -b-PFDMS(35)](4). The materials were synthesized by transition-metal-catalyzed ring-opening polymerization of dimethylsila[1]ferrocenophane in the presence of silane-functionalized four-arm PEO stars as macroinitiators and they exhibited a moderate polydispersity (PDI≅1.4). Self-assembly in mixtures of THF and different alcohols as selective solvents for the PEO block resulted in the formation of semicrystalline vesicles (ethanol, 1-butanol) or large, rather ill-defined, spherical structures (methanol). Further, both the rate of addition of the selective co-solvent and the overall solvent/non-solvent ratio drastically affected the size and stability of the self-assembled particles. We could also show that a photoacid generator, as a model for an active substance, can be encapsulated and the UV-induced generation of HCl resulted in a straightforward degradation of the organometallic vesicles.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Responsive Vesicles from the Self‐Assembly of Crystalline‐Coil Polyferrocenylsilane‐block‐Poly(ethylene Oxide) Star‐Block Copolymers

Schacher¹,

Elbert²,

Patra³

et al. 2011

Chemistry A European J

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“…A particularly elegant method to incorporate main-group elements into a polymer backbone is that of ring-opening polymerization (ROP) of strained sandwich compounds. [2] Significant advances in the synthesis and purification of monomers and in polymerization methods were made during the last two decades, in particular for the class of ferrocenophanes (FCPs). [3] The most developed strained sandwich compounds are silicon-bridged [1]FCPs (A; Figure 1), which can undergo living polymerization, [2,4] allowing the preparation of block copolymers.…”

Section: Introductionmentioning

confidence: 99%

Chiral Bora[1]ferrocenophanes: Syntheses, Mechanistic Insights, and Ring‐Opening Polymerizations

Sadeh

Bhattacharjee

Sarbisheh

et al. 2014

Chemistry A European J

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A series of new boron-bridged [1]ferrocenophanes ([1]FCPs) was prepared by salt-metathesis reactions between enantiomerically pure dilithioferrocenes and amino(dichloro)boranes (Et2 NBCl2 , iPr2 NBCl2 , or tBu(Me3 Si)NBCl2 ). The dilithioferrocenes were prepared in situ by lithium-bromine exchange from the respective planar-chiral dibromides (Sp ,Sp )-[1-Br-2-(HR2 C)H3 C5 ]2 Fe (R=Me or Et). In most of the cases, mixtures of the targeted [1]FCPs 4 and the unwanted 1,1'-bis(boryl)ferrocenes 5 were formed. The product ratio depends on the bulkiness of the amino group, the speed of addition of the amino(dichloro)borane, the alkyl group on Cp rings, and in particular on the reaction temperature. The formation of strained [1]FCPs is strongly favored by increased reaction temperatures. Secondly, CHEt2 groups at Cp rings favored the formation of the targeted [1]FCPs stronger than CHMe2 groups. These discoveries open up new possibilities to further suppress the formation of unwanted byproducts by a careful choice of the reaction temperature and through tailoring the bulkiness of CHR2 groups on ferrocene. Thermal ring-opening polymerizations of selected boron-bridged [1]FCPs gave metallopolymers with a Mw of 10 kDa (GPC).

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“…For example, well-defined BCs consisting of polyisoprene and polymers with laterally bonded alkyl-silane groups were recently prepared by sequential anionic polymerization and have been used as membranes for gas separation applications [22]. The anionic ring opening polymerization (ROP) of ring-strained cyclic silanes, carbosilanes and metal-containing carbosilanes has also been reported and lead to well-defined polymers [23][24][25][26][27][28][29][30][31][32]. Out of all cyclic carbosilanes, 1,1-dimethylsilacyclobutane (DMSB) is a well-known monomer, due to its convenient chemical and also commercial availability.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of Poly(1,1-dimethysilacyclobutane) by Means of Anionic Ring-Opening Polymerization on Organic Nanoparticles and Reinvestigation of Crystallization

Gallei

Elbert

et al. 2013

Polymers

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Abstract:In the present study, the synthesis of poly(1,1-dimethylsilacyclobutane) (PDMSB) by anionic ring opening polymerization (ROP) is reinvestigated, leading to narrowly distributed molar masses (polydispersities 1.04-1.15) in the range of 2.3 to 60 kg mol −1. Investigations of thermal behavior for low molar mass PDMSB revealed an untypical multiple peaks melting phenomenon, which at first glance, seems to be of the same origin as low molar mass poly(ethylene oxide)s. Small angle X-ray scattering (SAXS) and X-ray diffraction (XRD) measurements are done, proving the fast crystallization and subsequent recrystallization for investigated low molar mass samples. Synthetic attempts are expanded to the surface-initiated anionic ROP of 1,1-dimethylsilacyclobutane (DMSB) monomer from the surface of cross-linked polystyrene (PS) nanoparticles. Novel polycarbosilanes (PCS)/organic core/shell particles are obtained, which are investigated by using transmission electron microscopy (TEM) and dynamic light scattering (DLS) experiments. First insights into the crystallization behavior OPEN ACCESSPolymers 2013, 5 285 of surface-attached PDMSB chains reveal that crystallization seems to be hindered.

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Polyferrocenylsilan‐basierte Polymersysteme

Cited by 79 publications

References 304 publications

Responsive Vesicles from the Self‐Assembly of Crystalline‐Coil Polyferrocenylsilane‐block‐Poly(ethylene Oxide) Star‐Block Copolymers

Responsive Vesicles from the Self‐Assembly of Crystalline‐Coil Polyferrocenylsilane‐block‐Poly(ethylene Oxide) Star‐Block Copolymers

Chiral Bora[1]ferrocenophanes: Syntheses, Mechanistic Insights, and Ring‐Opening Polymerizations

Immobilization of Poly(1,1-dimethysilacyclobutane) by Means of Anionic Ring-Opening Polymerization on Organic Nanoparticles and Reinvestigation of Crystallization

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