Mesoporous silica-supported zirconocene catalysts for highly isotactic polypropyleneElectronic supplementary information (ESI) available: N2 absorption data, solid state NMR (13C, 29Si) and SEM micrographs of polymer samples. See http://www.rsc.org/suppdata/cc/b4/b403043e/

Miller, Catherine J.; O’Hare, Dermot

doi:10.1039/b403043e

Cited by 32 publications

(4 citation statements)

References 17 publications

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“…Shimada et al used this kind of reactivity for the immobilization of complex organic functionalities on silica surfaces . Despite the fact that immobilized indenyl groups are widely used as ligands in heterogeneous catalysis, ,− the herein described elimination reaction has not been considered until now.…”

Section: Resultsmentioning

confidence: 99%

Advanced Surface Functionalization of Periodic Mesoporous Silica: Kinetic Control by Trisilazane Reagents

et al. 2006

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The surface reactions of mesoporous silica MCM-41 with a series of new trisilylamines (trisilazanes) (SiHMe2)2NSiMe2R and (SiMe2Vin)2NSiMe2R (R = indenyl, norpinanyl, chloropropyl, 3-(N-morpholin)propyl; Vin = vinyl), disilylalkylamine (SiHMe2)iPrNSiMe2(CH2)3Cl, and monosilyldialkylamines Me2NSiMe2R (R = indenyl, chloropropyl, 3-(N-morpholin)propyl) were investigated. 1H, 13C, and 29Si MAS NMR spectroscopy, nitrogen adsorption/desorption, infrared spectroscopy, and model reactions with calix[4]arene as a mimic for an oxo surface were used to clarify the chemical nature of surface-bonded silyl groups. The trisilylamines exhibited a comparatively slow surface reaction, which allowed for the adjustment of the amount of silylated and nonreacted SiOH groups and led to a stoichiometric distribution of surface functionalities. The 2:1 integral ratio of SiHMe2 and SiMe2R moieties of such trisilazanes was found to be preserved on the silica surface as indicated by microanalytical as well as 13C and 29Si MAS NMR spectroscopic data of the hybrid materials. For example, the reaction of MCM-41 with (SiHMe2)2NSiMe2(CH2)3Cl, (SiHMe2)iPrNSiMe2(CH2)3Cl, and Me2NSiMe2(CH2)3Cl provided bi- and monofunctional hybrid materials with one-third, one-half, or all chemically accessible silanol groups derivatized by chloropropyl groups, respectively. Thus, a molecular precursor strategy was developed to efficiently control the relative amount of three different surface species, SiHMe2 (or SiVinMe2), SiMe2R, and SiOH, in a single reaction step. The reaction behavior of indenyl-substituted monosilazanes and trisilazanes (R = Ind) with calix[4]arene proved that the indenyl substituent can act as a leaving group forming a dimethylsilyl species, which is anchored bipodally on the silica surface, that is, via two Si-O bonds.

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Section: Resultsmentioning

confidence: 99%

Advanced Surface Functionalization of Periodic Mesoporous Silica: Kinetic Control by Trisilazane Reagents

et al. 2006

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“…A lot of research has been done to activate SBA-15 with various transition metal oxides in order to obtain large pore catalysts allowing high diffusion rates and a catalytic activity for bulky molecules. − Recently, a more mechanically stable analogue of SBA-15, namely plugged hexagonal templated silica (PHTS), was developed. The material is synthesized by an increased silica/surfactant ratio during the SBA-15 synthesis, which creates microporous amorphous nanoparticles (plugs) inside of the mesoporous channels of SBA-15. − Similar to SBA-15, it is composed of hexagonally ordered mesopores with thick pore walls, perforated with micropores.…”

Section: Introductionmentioning

confidence: 99%

Vanadium Silicalite-1 Nanoparticles Deposition onto the Mesoporous Walls of SBA-15. Mechanistic Insights from a Combined EPR and Raman Study

et al. 2006

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Continuous Wave (CW) and pulsed Electron Paramagnetic Resonance (EPR) spectroscopy in conjunction with Raman spectroscopy are used to investigate the properties of Vanadium Silicalite-1 (VS-1) nanoparticles dispersed onto the mesoporous walls of SBA-15 silica. The properties of the deposited zeolite nanoparticles are found to be remarkably different from those of the full grown VS-1 zeolite. Monitoring of the local VO2+ environment in the noncalcined nanoparticles in SBA-15 reveals that, in contrast to the full grown zeolite case, these sites are highly hydrophilic. Also, the stability of the TPAOH template is found to be affected by acidification of the nanoparticles. These results promise to be of great importance in elucidating the formation mechanism of TPAOH-templated zeolitic nanoparticles and their incorporation in mesoporous silica materials

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“…Recently, significant achievements in the preparation of ultrahigh molecular weight sPS nanofibrils in MAO-modified silica nanotube reactors with halftitanocen catalyst have been obtained [20]. Tethering a catalytic complex via a covalent anchoring of metallocene complexes on organic and inorganic supports, have been used extensively for the immobilization of single site catalyst in ethylene and propylene polymerization [21][22][23][24]. In this way, the active centers are firmly anchored to the support at all times with the hope that the catalyst will not leach or have enough freedom to deactivate via a bimolecular species during polymerization.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Tethered Half-Titanocene Complex on Syndiotactic Poly(styrene-co-p-methylstyrene) for Using in Syndiospecific Polymerization of Styrene

Rahmani

Entezami

2011

Catal Lett

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In this work the syndiotactic polystyrene copolymer, poly (styrene-co-p-methylstyrene) was prepared by the copolymerization of styrene and p-methylstyrene with cyclopentadienyltitanium trichloride/methylaluminoxane catalyst. This copolymer was functionalized with silylhydride groups. The structure of copolymer and functionalized copolymer were characterized by FT-IR, 1 H-NMR and 13 C-NMR spectroscopy. The obtained results revealed that the functionalization reaction successfully proceeds at low temperatures. Tethering of half-titanocene complex on polymeric support was done by the hydrosilylation reaction of 1-allylindenyltrichlorotitanium with silyl-hydride functionalized copolymer in the presence of Karstedt catalyst as a coupling reagent. The polymer-supported catalyst was tested for syndiospecific polymerization of styrene using methylaluminoxane as a cocatalyst. The results of styrene polymerization showed that the polymer-supported catalyst exhibited high activity for syndiospecific polymerization of styrene. The polymer prepared with supported catalyst was characterized by carbon nuclear magnetic resonance ( 13 C-NMR) and differential scanning calorimetry (DSC). The results confirmed the syndiotacticity of obtained polymers. X-ray diffraction (XRD) analysis showed the d-form crystalline structure of obtained syndiotactic polystyrene.

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Mesoporous silica-supported zirconocene catalysts for highly isotactic polypropyleneElectronic supplementary information (ESI) available: N2 absorption data, solid state NMR (13C, 29Si) and SEM micrographs of polymer samples. See http://www.rsc.org/suppdata/cc/b4/b403043e/

Cited by 32 publications

References 17 publications

Advanced Surface Functionalization of Periodic Mesoporous Silica: Kinetic Control by Trisilazane Reagents

Advanced Surface Functionalization of Periodic Mesoporous Silica: Kinetic Control by Trisilazane Reagents

Vanadium Silicalite-1 Nanoparticles Deposition onto the Mesoporous Walls of SBA-15. Mechanistic Insights from a Combined EPR and Raman Study

Preparation of Tethered Half-Titanocene Complex on Syndiotactic Poly(styrene-co-p-methylstyrene) for Using in Syndiospecific Polymerization of Styrene

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