The preparation, molecular structure and catalytic relevance of Ti(OSiPh3)4 and Ti(OGePh3)4

Johnson, Brian F. G.; Klunduk, Marek C.; Martin, Caroline M.; Sankar, Gopinathan; Teate, Simon J.; Thomas, John Meurig

doi:10.1016/s0022-328x(99)00744-5

Cited by 33 publications

(17 citation statements)

References 25 publications

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“…Other Ti-containing POSS, 1b and 2 (see Scheme 2), showed similar activities (entries 3 and 4). The activities of Ti-containing POSS as homogeneous catalysts for the epoxidation by organic peroxides have been previously reported [16][17][18][19][20][21][22][23]. Silica-tethered 1a showed a catalytic activity similar to that of 1a, indicating that 1a was tethered without a loss of activity (entry 5).…”

Section: Methodssupporting

confidence: 54%

“…In particular, the catalytic activities of Ti-containing POSS for the epoxidation of alkenes have been examined [16][17][18][19][20][21][22][23]. 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].…”

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: Methodssupporting

confidence: 54%

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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“…The synthesis and structural characterization of compound 2 have been reported previously, 1,13,27 but to the best of our knowledge the synthesis and characterization of 1, 3 and 4 have not been reported so far.…”

Section: Resultsmentioning

confidence: 91%

Synthesis, characterization and thermal behaviour of four homoleptic titanium silanolates

Mansfeld

Schürmann

Mehring

2005

Applied Organom Chemis

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“…With regard to the group 4 transition metal-containing silsesquioxanes, the catalytic activities for various reactions, i.e. the epoxidation of alkenes [2][3][4][5][6][7][8][9][21][22][23][25][26][27][28] and polymerization of small alkenes [2,3,16,17,[35][36][37][38], have been reported. In the course of our study on the preparation of novel group 4 metal-containing silsesquioxanes, we have successfully synthesized titanocenecontaining silsesquioxanes (2a-c) for the first time (equation 3) [39].…”

Section: Activities Of Vanadium or Titanium-containing Silsesquioxanementioning

confidence: 99%

“…These studies revealed that the molecules containing tripodal silsesquioxane ligands and a monomeric titanium species, which include three Si-O-Ti bondings between one silsesquioxane cage and one titanium center, act as active catalysts. After these reports, interest is focused on the utilization of metalcontaining silsesquioxanes as homogeneous oxidation catalysts [19][20][21][22][23][25][26][27][28]. Especially, a number of silsesquioxanes containing group 4 and 5 metallic species, mainly a titanium species, have been synthesized and their catalytic activities were evaluated.…”

Section: Introductionmentioning

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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The preparation, molecular structure and catalytic relevance of Ti(OSiPh3)4 and Ti(OGePh3)4

Cited by 33 publications

References 25 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

Synthesis, characterization and thermal behaviour of four homoleptic titanium silanolates

Preparation of Novel Materials for Catalysts Utilizing Metal-Containing Silsesquioxanes

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