Hetero- and Metallasiloxanes Derived from Silanediols, Disilanols, Silanetriols, and Trisilanols

Murugavel, Ramaswamy; Voigt, Andreas; Walawalkar, Mrinalini G.; Roesky, Herbert W.

doi:10.1021/cr9500747

Cited by 597 publications

(335 citation statements)

References 196 publications

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“…Octahedral derivatives are the most representative ones of this family. POSSs have been extensively studied as a starting substrate to construct nanocomposites with precise control of nanoarchitecture and properties [5][6][7][8][9][10][11]. However, the procedure of blending POSS in a polymer matrix often meets severe problems with aggregation of POSS units, limiting the POSS amount introduced deteriorating the properties [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Green Nanocomposites from Renewable Plant Oils and Polyhedral Oligomeric Silsesquioxanes

Tsujimoto

Uyama

Kobayashi

et al. 2015

Metals

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Abstract:Green nanocomposites based on renewable plant oils and polyhedral oligomeric silsesquioxanes (POSS) have been developed. An acid-catalyzed curing of epoxidized plant oils with oxirane-containing POSS derivatives produced transparent nanocomposite coatings with high gloss surface, in which the organic and inorganic components were linked via covalent bonds. The hardness and mechanical strength were improved by the incorporation of the POSS unit into the organic polymer matrix. Nanostructural analyses of the nanocomposites showed the formation of homogeneous structures at the micrometer scale. On the other hand, such improvements of the coating and mechanical properties were not observed in the composite without covalent bonds between the plant oil-based polymer and POSS unit. The study demonstrates the correlation between the nanostructure of composites and macroscopic properties.

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Section: Introductionmentioning

confidence: 99%

Green Nanocomposites from Renewable Plant Oils and Polyhedral Oligomeric Silsesquioxanes

Tsujimoto

Uyama

Kobayashi

et al. 2015

Metals

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“…실리카에 있는 실란올의 반응성은 규소 원소에 치환된 −OH 기의 수가 증가할수록 커지는 것으로 알려져 있다. 3,4 또한 실리카는 실란 커플링제에 의해 표면이 개질될 수 있으며, 실란 커플링제는 용매 내에서 가수분해반응과 축합반응이 일어나는 것으로 알려져 있다. 5 유기계 실란 커플링제는 유기와 무기의 특성을 모두 가진 구조로서 일 반식은 R n -Si-(OR') 3 로 나타낸다.…”

Section: 서 론unclassified

Quantitative Analysis of Silanization Degree of Silica Nanoparticles Modified with Bis[3-(trimethoxysilyl)propyl]amine Coupling Agent

Jeon¹,

Kim²,

Ha³

2012

Polymer Korea

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In this study, we treated silica nanoparticles with bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to modify their surfaces. We investigated the effects of BTMA hydrolysis time, BTMA concentration and BTMA treatment time on the degree of silanization reaction of silica nanoparticles. We used Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to obtain quantitative data. We found the decrease of isolated Si-OH peak intensity at 3747 cm −1 and the increase of −CH 2 stretching and bending peaks with increasing hydrolysis time, concentration and treatment time of BTMA. EA analysis results also supported this trend. We found a strong effect of BTMA concentration on the degree of silanization of the silica particles, but weak effects of the hydrolysis time and the treatment time.

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“…Indeed, several heterometallic metallasiloxanes of attractive cage-like molecular geometry were described [14][15][16][17]. Importantly, Fe-containing siloxanes may be regarded as the most attractive representatives of metallasiloxanes, being artificial models of catalytically prospective silicates, zeolites and iron oxides.…”

Section: Introductionmentioning

confidence: 99%

“…As a pair of metal ions, a Fe/Na combination has been chosen because of the following reasons. It is known that sodiumcontaining heterometallic cage siloxanes provide exceptional variety of architecture [14][15][16][17] as well as catalytic activities [16,17,19,20] and magnetic (spin glass) properties [21][22][23][24]. It is explained by the participation of specific siloxanolate [RSi(O)ONa] ligand in cage construction, giving rise to multiple metallasiloxane architectures [17].…”

Section: Introductionmentioning

confidence: 99%

High Catalytic Activity of Heterometallic (Fe6Na7 and Fe6Na6) Cage Silsesquioxanes in Oxidations with Peroxides

Yalymov

Bilyachenko

Levitsky

et al. 2017

Preprint

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Two types of heterometallic (Fe(III),Na) silsesquioxanes [Ph5Si5O10]2[Ph10Si10O21]Fe6(O2‒)2Na7(H3O+)(MeOH)2(MeCN)4.5.1.25(MeCN), I, and [Ph5Si5O10]2[Ph4Si4O8]2Fe6Na6(O2‒)3(MeCN)8.5(H2O)8.44, II, were obtained and characterized. X-Ray studies established distinctive structures of both products, with pair of Fe(III)-O-based triangles surrounded by siloxanolate ligands, giving fascinating cage architectures. Complex II proved to be catalytically active in the formation of amides from alcohols and amines, thus becoming a rare example of metallasilsesquioxanes performing homogeneous catalysis. Benzene, cyclohexane and other alkanes, as well as alcohols, can be oxidized in acetonitrile solution to phenol, the corresponding alkyl hydroperoxides and ketones, respectively, by hydrogen peroxide in air in the presence of catalytic amounts of complex II and trifluoroacetic acid. Thus, the cyclohexane oxidation at 20 °C gave oxygenates in very high for alkanes yield (48% based on alkane). The kinetic behaviour of the system indicates that the mechanism includes the formation of hydroxyl radicals generated from hydrogen peroxide in its interaction with diiron species. The latter are formed via monomerization of starting hexairon complex with further dimerization of the monomers.

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Hetero- and Metallasiloxanes Derived from Silanediols, Disilanols, Silanetriols, and Trisilanols

Cited by 597 publications

References 196 publications

Green Nanocomposites from Renewable Plant Oils and Polyhedral Oligomeric Silsesquioxanes

Green Nanocomposites from Renewable Plant Oils and Polyhedral Oligomeric Silsesquioxanes

Quantitative Analysis of Silanization Degree of Silica Nanoparticles Modified with Bis[3-(trimethoxysilyl)propyl]amine Coupling Agent

High Catalytic Activity of Heterometallic (Fe<sub>6</sub>Na<sub>7 </sub>and Fe<sub>6</sub>Na<sub>6</sub>) Cage Silsesquioxanes in Oxidations with Peroxides

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