Facile Framework Cleavage Reactions of a Completely Condensed Silsesquioxane Framework

Feher, Frank J.; Soulivong, Daravong; Lewis, Gregory T.

doi:10.1021/ja972436t

Cited by 59 publications

(46 citation statements)

References 39 publications

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“…4,14-18 A smaller peak in the region -54 to -62 ppm, with maxima at -58.8 and -60.3 ppm, was assigned to Si atoms bonded to three other Si atoms through Si-O-Si bonds, present in strained Si 3 O 3 rings, and to Si atoms bonded to two other Si atoms through Si-O-Si bonds and to an OH group (or eventually a methoxy group). 4,19,20 Small peaks at -42.52 and -50.83 ppm were assigned to the monomer and dimer that are still present in the final products. 19,21 FTIR spectra showed that a relatively low amount of SiOH groups still persisted as revealed by the presence of a small band at 3485 cm -1 .…”

Section: Resultsmentioning

confidence: 99%

Cagelike Precursors of High-Molar-Mass Silsesquioxanes Formed by the Hydrolytic Condensation of Trialkoxysilanes

et al. 2000

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High-molar-mass silsesquioxanes (SSQO) based on (3-glycidoxypropyl)trimethoxysilane (GPMS) and (3-methacryloxypropyl)trimethoxysilane (MPMS) were synthesized. The hydrolytic condensation of GPMS was performed using HCOOH (0.1 N) as catalyst, keeping the molar ratio H 2O/Si ) 3. A first step was performed in tetrahydrofuran (THF) at 50°C, followed by a second step in diglycidyl ether of bisphenol A (DGEBA), where temperature was increased in steps up to 140°C. The hydrolytic condensation of MPMS was performed in bulk with HCOOH 98%, at T ) 50 or 70°C, using molar ratios of HCOOH/Si ) 3 or 6. Homogeneous solutions were obtained for both silanes. The reaction was followed by size exclusion chromatography (SEC), and final products were characterized by matrix-assisted ultraviolet laser desorption/ionization time-of-flight mass spectrometry (UV-MALDI-TOF MS), FTIR, and 1 H and 29 Si NMR. Molar-mass distributions showed the presence of clusters corresponding to products formed in different generations. With the aid of UV-MALDI-TOF MS, the different species present in every cluster could be identified for one of the silsesquioxanes derived from MPMS. During the initial stage of the hydrolytic condensation, species with 7-12 Si atoms were produced. They mainly consisted of incompletely condensed polyhedra (species with 1-3 OH per molecule) and ladder-type structures (species with 4 OH per molecule). Species with more OH groups were condensed with a higher probability, giving place to a second generation of products. This process accounts for the presence of a cluster of species with 14-24 Si atoms and the enrichment of the first cluster in the more condensed structures (T 7(OH), T8(OH)2, and T9(OH)). Third and fourth generations of condensation products were also present. Structures of different species may be depicted as combinations of incompletely condensed polyhedra with ladder fragments.

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Section: Resultsmentioning

confidence: 99%

Cagelike Precursors of High-Molar-Mass Silsesquioxanes Formed by the Hydrolytic Condensation of Trialkoxysilanes

et al. 2000

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“…The stoichiometry of these compounds shows each silicon atom bonded to one-and-a-half oxygens (sesqui-) and to a hydrocarbon (-ane), which leads to (RSiO 1.5 ) units. [1][2][3] Besides fully con-densed polyhedral silsesquioxanes, which are essentially centred on cubic R 8 3 ], which can generally be obtained by direct synthesis from specific chlorosilanes [1][2][3][4][5] or by cleavage of completely condensed POSS, [6][7] are far more interesting due to the possibility of further functionalisation both with specific organosilanes and with heteroelements. In particular, these compounds ( Figure 1) are suitable for reaction with a variety of transition metal complexes (in the form of alkoxides or chlorides) to form completely condensed metal-silsesquioxanes (M-POSS).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterisation of Metal Isobutylsilsesquioxanes and Their Role as Inorganic–Organic Nanoadditives for Enhancing Polymer Thermal Stability

et al. 2007

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Metal isobutylsilsesquioxanes (M-POSS) with TiIV and V V metal centres have been prepared by direct corner-capping of trisilanolisobutyl-POSS (1). The synthetic procedure has been followed in solution by FTIR spectroscopy and samples have been characterised by 29 Si{ 1 H} NMR, FTIR, FT-Raman and UV/Vis spectroscopy in order to study the structure and the chemical properties of the transition metal centres incorporated in the synthesised compounds. The corner-capping reaction basically lead to tetrahedrally coordinated metal centres inserted in the siliceous cage. The hybrid inorganicorganic nature of these compounds and the possibility of dispersing catalytically active metal centres in a highly efficient way within organic matrices have been investigated by dispersing the title compounds at 3 wt.-% in a polypropylene

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“…Reports regarding modified incompletely condensed silsesquioxanes are scarce . However, these compounds exhibit distinct physicochemical properties and different reactivities .…”

Section: Introductionmentioning

confidence: 99%

Vinyl‐Functionalized Silsesquioxanes and Germasilsesquioxanes

2017

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We report herein an efficient procedure for the synthesis of new polyhedral oligomeric silsesquioxane (POSS) derivatives as multifunctional reagents. This study concerns the incompletely condensed silsesquioxanes and germasilsesquioxanes with vinyl‐substituted silyl and germyl functional groups, which allow further modification. Furthermore, our experiments have been extended to the synthesis of a new subclass of completely condensed vinylgermasilsesquioxanes. These hybrid building blocks were obtained selectively within a few hours and isolated with excellent yields.

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Facile Framework Cleavage Reactions of a Completely Condensed Silsesquioxane Framework

Cited by 59 publications

References 39 publications

Cagelike Precursors of High-Molar-Mass Silsesquioxanes Formed by the Hydrolytic Condensation of Trialkoxysilanes

Cagelike Precursors of High-Molar-Mass Silsesquioxanes Formed by the Hydrolytic Condensation of Trialkoxysilanes

Synthesis and Characterisation of Metal Isobutylsilsesquioxanes and Their Role as Inorganic–Organic Nanoadditives for Enhancing Polymer Thermal Stability

Vinyl‐Functionalized Silsesquioxanes and Germasilsesquioxanes

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