Synthesis and characterization of cage and bicyclic silsesquioxanes via dehydration of silanols

Unno, Masafumi; Alias, Shamsul Bahri; Arai, Miwako; Takada, Keisuke; Tanaka, Ryoji; Matsumoto, Hideyuki

doi:10.1002/(sici)1099-0739(199904)13:4<303::aid-aoc846>3.0.co;2-#

Cited by 44 publications

(12 citation statements)

References 16 publications

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“…Compound 3 has been already described in the literature together with its spectroscopic data [21]. The 29 Si-chemical shift of T 6 cage 3 at −56.3 ppm in DMSO solution observed by us is very similar to the previously reported one (−54.4, CDCl 3 ) and fits well in the range observed for alkyl substituted T 6 cages [16,21] but resonates at a lower field than the comparable T 8 -cages [10,12,14,16,22]. Compound 3 could be obtained as single crystals suitable for X-ray diffraction and crystallizes in the orthorhombic space group Ccce.…”

Section: Resultssupporting

confidence: 87%

Preparation and Molecular Structure of a Cyclopentyl-Substituted Cage Hexasilsesquioxane T6 (T = cyclopentyl-SiO1.5) Starting from the Corresponding Silanetriol

2017

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Cyclopentyl substituted silanetriol can be prepared and isolated. Its condensation yields the corresponding disiloxanetetrol as a primary condensation product. Further condensation leads to the hexameric polyhedral silsesquioxane cage T 6 . The latter has been mentioned in the literature before however, lacking structural data. All compounds have been characterized with multinuclear NMR spectroscopy and, in addition, the molecular structures have been determined in the case of the disiloxanetetrol and the hexasilsesquioxane via single crystal X-ray diffraction.

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Section: Resultssupporting

confidence: 87%

Preparation and Molecular Structure of a Cyclopentyl-Substituted Cage Hexasilsesquioxane T6 (T = cyclopentyl-SiO1.5) Starting from the Corresponding Silanetriol

2017

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“…The main peak at À65.8 ppm in 29 Si NMR spectra may be assigned to both octahedral [33][34][35][36][37] or ladder structures. [38,39] Decahedra (characteristic peak at about À68 ppm) and dodecahedra (characteristic peaks at À68 and À71 ppm), [35] could also be present but in very small amounts. Therefore, inorganic domains must be present as octahedral, ladder structures, or blends of both types of structures.…”

Section: Resultsmentioning

confidence: 99%

Bridged Silsesquioxanes with Organic Domains Self‐Assembled as Functionalized Molecular Channels

Romeo

Fanovich

Williams

et al. 2007

Macro Chemistry & Physics

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A bridged silsesquioxane was obtained from a precursor synthesized by the reaction of glycidoxypropyl(trimethoxysilane) (2 mol) with cyclohexylamine (1 mol). The polycondensation in the presence of formic acid produced a hybrid material exhibiting a short‐range order based on elongated organic channels accommodating the pendant cyclohexyl fragments, bounded by inorganic domains. The presence of functional groups in the organic channels (tertiary amine, ether, hydroxyl), can be used to retain small organic molecules capable of forming hydrogen bonds. Aspirin was used as a probe to illustrate this possibility.magnified image

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“…In this PhNH 2 -catalyzed system, the high conversion attained in the inorganic polycondensation suggests that silsesquioxane domains are present as polyhedra or ladder structures. [45][46][47][48][49][50] In the previous section where the hydrolysis-condensation process was examined by means of ATR-FTIR technique, it was run that, in the PhSO 3 H-catalyzed composite, the condensation step did not progress to the same extent achieved by PhNH 2 catalyst (see Fig. 1).…”

Section: /28mentioning

confidence: 99%

Ethylene–propylene copolymer/ordered polysilsesquioxane nanocomposites prepared via organic acid‐ or base‐catalyzed binary silica water‐crosslinking reactions

Adachi

Hirano²,

Kasai³

et al. 2009

Polymer International

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BACKGROUND:In-situ silica sol-gel derived organic-inorganic hybrid materials, which comprise a vinyltrimethoxysilane-grafted ethylene-propylene copolymer (EPR-g-VTMS) and n-hexyltrimethoxysilane (HTMS), were successfully prepared in the presence of an organic acid and base catalyst. Benzenesulfonic acid (PhSO 3 H) and aniline (PhNH 2 ) were selected as the organic acid and base catalyst, respectively, to examine the progress and effect of progressive changes in the silane water-crosslinking reaction of EPR-g-VTMS/HTMS composites. RESULTS:The water-crosslinked EPR-g-VTMS/HTMS composites were characterized by means of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), solid-state silicon-29 cross polarization/magic angle spinning-nuclear magnetic resonance ( 29 Si CP/MAS NMR), wide-angle X-ray scattering (WAXS), tensile strength, and field emission-scanning electron microscope (FE-SEM) measurements. CONCLUSION:These results revealed that the type of catalyst has a substantial influence on the nature of siloxane bands and eventually the physical tensile properties of the water-crosslinked EPR-g-VTMS/HTMS composites, which can be explained mainly on the knowledge of the traditional acid-and base-catalyzed silica sol-gel reaction. Moreover, the in-depth analysis for the PhNH 2 -catalyzed composites indicated the formation of ladder-type poly(n-hexyl silsesquoxane)s and the presence of the highly-ordered structure with a thickness equal to the length of two n-hexyl groups in all-trans conformation. In the present study, we demonstrated a potential for future design of highly-ordered silicate-based organic-inorganic hybrid nanocomposites.3/28

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Synthesis and characterization of cage and bicyclic silsesquioxanes via dehydration of silanols

Cited by 44 publications

References 16 publications

Preparation and Molecular Structure of a Cyclopentyl-Substituted Cage Hexasilsesquioxane T6 (T = cyclopentyl-SiO1.5) Starting from the Corresponding Silanetriol

Preparation and Molecular Structure of a Cyclopentyl-Substituted Cage Hexasilsesquioxane T6 (T = cyclopentyl-SiO1.5) Starting from the Corresponding Silanetriol

Bridged Silsesquioxanes with Organic Domains Self‐Assembled as Functionalized Molecular Channels

Ethylene–propylene copolymer/ordered polysilsesquioxane nanocomposites prepared via organic acid‐ or base‐catalyzed binary silica water‐crosslinking reactions

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