Synthesis and characterisation of microporous bimetallic Fe–Cr–Si–O materials derived from silsesquioxane precursors

Maxim, Nicolae; Overweg, A.R.; Kooyman, Patricia J.; Nagy, Anton J.; Santen, Rutger A. van; Abbenhuis, Hendrikus C. L.

doi:10.1039/b205051j

Cited by 24 publications

(13 citation statements)

References 37 publications

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“…While the formation of micropores by the calcination of POSS molecules has been previously reported [32][33][34][35][36][37][38][39][40][41][42][43][44], an increase in the BET surface area by the calcination of silica-supported POSS was not recognized from the results shown in Table 4, probably because of a low loading level of POSS.…”

Section: Characterization Of the Oxide Catalysts Prepared Using Ti-posscontrasting

confidence: 45%

“…In addition to their activities as homogeneous catalysts, their application to heterogeneous catalysis using metal-containing POSS as precursors has been examined [10,13,15,[24][25][26][27][28][29][30][31]. The preparation of microporous silicas containing well-dispersed metal oxide species by the controlled calcination of metal-containing POSS has been reported [32][33][34][35][36][37][38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

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Ti-bridged silsesquioxanes as precursors of silica-supported titanium oxide catalysts for the epoxidation of cyclooctene

Sakugawa

Wada

Inoue

2010

Journal of Catalysis

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ABSTRACT:Silica-supported titanium oxide catalysts were prepared by the controlled calcination of Ti-bridged polyhedral oligomeric silsesquioxanes (POSS) bearing four Si-O-Ti bonds, Ti[(c-C 5 H 9 ) 7 Si 7 O 11 (OSiMe 2 R)] 2 (1a; R = vinyl, 1b; R = methyl) and Ti[(c-C 5 H 9 ) 8 Si 8 O 13 )] 2 (2), supported on various silicas, and these catalysts showed excellent activities for the epoxidation of cyclooctene by t BuOOH as an oxidant to selectively give cyclooctene oxide in high yields. On the other hand, catalysts prepared using a corner-capped-type Ti-containing POSS, CpTi[(c-C 5 H 9 ) 7 Si 7 O 12 ] (3, Cp = cyclopentadienyl), or tetraisopropoxytitanium (4) showed lower activities. The 2 catalysts prepared from Ti-bridged POSS can be easily separated from the reaction mixture and reused without a significant loss of activity. These catalysts were also applicable for the epoxidation of limonene. A spectroscopic study revealed that calcination of Ti-bridged POSS supported on silica gave isolated tetrahedral Ti(IV) species, which would be responsible for the high activity, while calcination of silicasupported 3 or 4 gave aggregated surface titanium oxide species.

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Section: Characterization Of the Oxide Catalysts Prepared Using Ti-posscontrasting

confidence: 45%

Section: Introductionmentioning

confidence: 99%

Ti-bridged silsesquioxanes as precursors of silica-supported titanium oxide catalysts for the epoxidation of cyclooctene

Sakugawa

Wada

Inoue

2010

Journal of Catalysis

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“…Irrespective of the kinds of precursor molecules, the pore size of the oxides in these studies falls within the range found in the porous materials prepared by the thermal treatment of discrete silsesquioxane molecules, including metallic species or not [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62], and silsesqioxane polymers [81,91]. The thermogravimetric analyses support the idea that complete loss of the counter cation occurs during the heat-up before the formation of micropores started by the combustion of the cyclopentyl groups.…”

Section: Preparation Of Porous Oxide Catalysts Utilizing Metalcontainmentioning

confidence: 60%

“…Microporous amorphous Fe-Si-O materials with adjustable iron content have been prepared by the calcination of mixtures of an iron-containing silsesquioxane and a metal-free one, which show the activity for ammonia oxidation and N 2 O decomposition [60]. The calcination of a three-component mixture of iron and chromium-containing molecules and metal-free molecules yields bimetallic Fe-Cr-Si-O materials [61]. They also reported the formation of Lewis acidic microporous oxides by the calcination of Bro¨nsted acidic aluminosilsesquioxane,…”

Section: Preparation Of Porous Oxide Catalysts Utilizing Metalcontainmentioning

confidence: 99%

Preparation of Novel Materials for Catalysts Utilizing Metal-Containing Silsesquioxanes

Wada

Mitsudo

2005

Catal Surv Asia

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Recent progress of the preparation of novel materials for catalysts utilizing metal-containing silsesquioxanes are reviewed in the following categories: (i) activities of vanadium or titanium-containing silsesquioxanes as homogeneous catalysts for oxidative reactions, (ii) preparation of immobilized or polymeric catalysts, and (iii) preparation of porous oxide catalysts utilizing metalcontaining silsesquioxanes. The present authors found that the liquid phase photo-oxidation of cyclohexane in the presence of a vanadium-containing silsesquioxane as a homogeneous catalyst selectively afforded cyclohexanol and cyclohexanone in high yields. Facile synthetic methods for group 4 metal-containing silsesquioxanes with functionalized silyl (or germyl) groups are presented. Remarkably, titanocene(IV)-containing silsesquioxanes have been synthesized for the first time. The presence of alkenylsilyl substituents shows a promotional effect on the epoxidation of cycloalkenes, which was found to be more significant for titaniumbridged silsesquioxanes. By utilizing these silsesquioxanes, polymeric, starburst-like, and dendritic silsesquioxanes were prepared as well as novel caged or macrocyclic molecules with organic-inorganic hybrid structures. The controlled calcination of these metalcontaining silsesquioxanes at around 823 K produces porous oxides with high BET surface areas of 300-520 m 2 g )1 and uniformlycontrolled micropores of 0.5-0.6 nm diameter. The oxides are found to include a well-dispersed metallic oxide species. From group 13 elements-containing silsesquioxanes Bro¨nsted acidic oxides are produced. Among them, aluminum-containing oxides show excellent activities for the cracking of cumene even at low temperature, 523 K, in spite of their amorphous nature.

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“…Reaction of in situ prepared (c-C 6 H 11 ) 7 Si 7 O 9 (OLi) 3 with anhydrous ErCl 3 in thf solution afforded the large heterometallic (Er/Li) metallasilsesquioxane cluster (c-C 6 H 11 ) 21 Si 21 O 36 (SiMe 3 )Er 2 (thf) 2 -Li 4 Cl 2 (2) in good yield (65 %). The molecular structure of 2…”

mentioning

confidence: 96%

Coupling of Silsesquioxane Cages in the Coordination Sphere of Erbium

et al. 2010

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Keywords: Lanthanides / Silsesquioxanes / Metallasilsesquioxanes / Erbium / Cluster compounds A novel transformation of silsesquioxane cages in the coordination sphere of a lanthanide ion is reported. Reaction of in situ prepared (c-C 6 H 11 ) 7 Si 7 O 9 (OLi) 3 with anhydrous ErCl 3 in thf solution afforded the large heterometallic (Er/Li) metallasilsesquioxane cluster (c-C 6 H 11 ) 21 Si 21 O 36 (SiMe 3 )Er 2 (thf) 2 -Li 4 Cl 2 (2) in good yield (65 %). The molecular structure of 2

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Synthesis and characterisation of microporous bimetallic Fe–Cr–Si–O materials derived from silsesquioxane precursors

Cited by 24 publications

References 37 publications

Ti-bridged silsesquioxanes as precursors of silica-supported titanium oxide catalysts for the epoxidation of cyclooctene

Ti-bridged silsesquioxanes as precursors of silica-supported titanium oxide catalysts for the epoxidation of cyclooctene

Preparation of Novel Materials for Catalysts Utilizing Metal-Containing Silsesquioxanes

Coupling of Silsesquioxane Cages in the Coordination Sphere of Erbium

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