The polyoctahedral silsesquioxane (POSS) 1,3,5,7,9,11,13,15-octaphenylpentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane (octaphenyl-POSS)

Chinnam, Parameswara Rao; Gau, Michael R.; Schwab, Joseph J.; Zdilla, Michael J.; Wunder, Stephanie L.

doi:10.1107/s2053229614019834

Cited by 9 publications

(7 citation statements)

References 28 publications

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“…The mixture was stirred for 3 h and left to rest at room temperature. The product was separated as single crystals, and the structure was elucidated by single crystal X‐Ray diffraction, being identical with the structure reported in Reference 34. (Yield: 9.03 g; 22.91%).…”

Section: Methodssupporting

confidence: 73%

Octakis(phenyl)‐T8‐silsesquioxane‐filled silicone elastomers with enhanced electromechanical capability

Dascălu¹,

Iacob²,

Tugui³

et al. 2020

J of Applied Polymer Sci

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The first dielectric elastomer actuators based on electroactive nanocomposites with octakis(phenyl)-T8-silsesquioxane (phenyl-T8), obtained ex-situ, used as voltage stabilizer filler for silicone elastomers are reported. The incorporation and homogeneous dispersion of crystalline phenyl-T8 in percentages of 2.5, 3.5, 5, and 10 into the amorphous matrix consisting in a polydimethylsiloxane-α,ω-diol with Mn = 240,000 g/mol was successfully achieved by solution mixing and crosslinking. For the sample with the best actuation performance (that containing 3.5 wt.% filler), an optimized filled elastomer was obtained by dispersing 3.6 wt. % phenyl-T8 in the matrix using a suitable surfactant (Pluronic L81), thus gaining an increased electrical breakdown of 30% compared with the pristine sample. Beside dielectric strength, the matured films were characterized in terms of morphology, mechanical, dielectric and actuation tests. In spite of structural incompatibility between the filler and the matrix, the obtained materials are soft elastomers showing high strain (~800%) and low Young's modulus of 50-100 kPa. The use of phenyl-T8 in a silicone matrix lead to electroactive films with slightly increased lateral actuation strain and electric breakdown strength.

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Section: Methodssupporting

confidence: 73%

Octakis(phenyl)‐T8‐silsesquioxane‐filled silicone elastomers with enhanced electromechanical capability

Dascălu¹,

Iacob²,

Tugui³

et al. 2020

J of Applied Polymer Sci

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“…Test reaction of anionic siliconoid 1 with benzyl bromide to obtain benzyl functionalized hexasilabenzpolarene. pending ethylene moiety (Si7À C39 1.838(3) Å) is identical within the margin of error to the SiÀ C distances involving the T 8phenyl substituents and indistinguishable from those reported for T 8 Ph 8 [27] (1.838(2) to 1.843(2) Å) as well as an octa(pcarboxyphenylethyl)-T 8 (1.840(4) to 1.851(4) Å). [28] The SiO bond lengths of the T 8 cage are between 1.606(2) Å and 1.627(2) Å, thus showing slightly more variance compared to T 8 Ph 8 (1.6166(11) to 1.6258(11) Å).…”

Section: Resultssupporting

confidence: 57%

Interlinkage of a siliconoid with a silsesquioxane: en route to a molecular model system for silicon monoxide

Hunsicker

Poitiers

Hüch

et al. 2022

Zeitschrift anorg allge chemie

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A new potential model system for silicon monoxide (SiO) is synthesized by the interlinkage of an unsaturated silicon cluster (siliconoid) with a polyhedral silsequioxane cage. Two derivatives with variable linker size are obtained by the corner‐capping reaction of Ph7T7(ONa)3 with a trichlorosilane featuring a remote benzylic chloride functionality and the subsequent nucleophilic substitution of the latter by the anionic hexasilabenzpolarene‐type Si6 siliconoid. Based on the recently proposed heterogeneous cluster model for the SiO structure, the stoichiometry between silicon and oxygen reiterates the suboxidic interface of the nano‐composite in a Si : O ratio of 14 : 12.

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“…The structure of O-POSS (Figure A) may be described as a cube-shaped arrangement of Si atoms with interstitial cuboctahedron of connecting O atoms . The D-POSS has been reported with a hexagonal-prismatic arrangement consisting of fused eight- and ten-membered silicon–oxygen rings (Figure B) …”

Section: Resultsmentioning

confidence: 99%

Hydrophobic Polyhedral Oligomeric Silsesquioxane Support Enhanced Methanol Production from CO₂ Hydrogenation

Herrero

Ullah

2023

ACS Appl. Mater. Interfaces

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The abundance of CO 2 from the cement industry, power generation, petroleum production, and combustion of biomass makes it a readily available feedstock to produce chemicals and materials, although it has yet to achieve optimal development. Even though syngas (CO + H 2 ) hydrogenation to methanol is an established industrial process, when the same catalytic system based on Cu/ZnO/Al 2 O 3 is employed with CO 2 , the water formed as a byproduct reduces the activity, stability, and selectivity of the process. Here, we explored the potential of phenyl polyhedral oligomeric silsesquioxane (POSS) as a hydrophobic support of Cu/ZnO for direct CO 2 hydrogenation to methanol. Mild calcination of the copper−zinc-impregnated POSS material affords the formation of CuZn-POSS nanoparticles with Cu and ZnO homogeneously dispersed with an average particle size of 7 and 15 nm supported on O-POSS and D-POSS, respectively. The composite supported on D-POSS was able to reach a 3.8% yield of methanol with a 4.4% of CO 2 conversion and with selectivity as high as 87.5% within 18 h. The structural investigation of the catalytic system reveals that CuO/ZnO are electron withdrawers in the presence of the siloxane cage of POSS. The catalytic system metal-POSS is stable and recyclable under H 2 reduction and CO 2 /H 2 conditions. We tested the use of microbatch reactors in heterogeneous reactions as a rapid and effective tool for catalyst screening. The increased number of phenyls in the structure of POSS results in an increased hydrophobic character that plays a decisive role in the methanol formation after comparison with CuO/ ZnO supported on reduced graphene oxide with 0% selectivity to methanol under the study conditions. The materials were characterized using scanning electron microscopy, transmission electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, Fourier transform infrared analysis, Brunauer− Emmett−Teller specific surface area analysis, contact angle, and thermogravimetry. The gaseous products were characterized by gas chromatography coupled with thermal conductivity detectors and flame ionization detectors.

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The polyoctahedral silsesquioxane (POSS) 1,3,5,7,9,11,13,15-octaphenylpentacyclo[9.5.1.1^3,9.1^5,15.1^7,13]octasiloxane (octaphenyl-POSS)

Cited by 9 publications

References 28 publications

Octakis(phenyl)‐T8‐silsesquioxane‐filled silicone elastomers with enhanced electromechanical capability

Octakis(phenyl)‐T8‐silsesquioxane‐filled silicone elastomers with enhanced electromechanical capability

Interlinkage of a siliconoid with a silsesquioxane: en route to a molecular model system for silicon monoxide

Hydrophobic Polyhedral Oligomeric Silsesquioxane Support Enhanced Methanol Production from CO₂ Hydrogenation

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The polyoctahedral silsesquioxane (POSS) 1,3,5,7,9,11,13,15-octaphenylpentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane (octaphenyl-POSS)

Cited by 9 publications

References 28 publications

Octakis(phenyl)‐T8‐silsesquioxane‐filled silicone elastomers with enhanced electromechanical capability

Octakis(phenyl)‐T8‐silsesquioxane‐filled silicone elastomers with enhanced electromechanical capability

Interlinkage of a siliconoid with a silsesquioxane: en route to a molecular model system for silicon monoxide

Hydrophobic Polyhedral Oligomeric Silsesquioxane Support Enhanced Methanol Production from CO2 Hydrogenation

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Product

Resources

About

The polyoctahedral silsesquioxane (POSS) 1,3,5,7,9,11,13,15-octaphenylpentacyclo[9.5.1.1^3,9.1^5,15.1^7,13]octasiloxane (octaphenyl-POSS)

Hydrophobic Polyhedral Oligomeric Silsesquioxane Support Enhanced Methanol Production from CO₂ Hydrogenation