Studies of octameric vinylsilasesquioxane by carbon-13 and silicon-29 cross polarization magic angle spinning and inversion recovery cross polarization nuclear magnetic resonance spectroscopy

Bonhomme, Christian; Tolédano, P.; Maquet, Jocelyne; Livage, Jacques; Bonhomme-Coury, Laure

doi:10.1039/a700700k

Cited by 55 publications

(49 citation statements)

References 31 publications

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“…The macromolecules presented in this section and sharing the common formula [RSiO 1,5 ] 8 , that is, octavinylsilsesquioxane (OVS, R = C 2 H 3 ) and octaphenylsilsesquioxane (OPS, R = C 6 H 5 ), have previously been investigated . In this article, we will give a detailed interpretation of the valence region of the XPS spectra of polycrystals in the solid state.…”

Section: Methodsmentioning

confidence: 99%

“…[55] R 5 AC 6 H 5 ), have previously been investigated. [58][59][60][61] In this article, we will give a detailed interpretation of the valence region of the XPS spectra of polycrystals in the solid state. We correlated the calculated valence levels and spectral maxima in the range of 23 to 230 eV.…”

Section: Macromolecular Octavinylsilsesquioxane and Octaphenylsilsesqmentioning

confidence: 99%

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Application of DFT for the modeling of the valence region photoelectron spectra of boron and d‐element complexes and macromolecules

Osmushko

Vovna

Tikhonov

et al. 2015

Int J of Quantum Chemistry

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Using density functional theory (DFT) in conjunction with ultraviolet (UPS) and X‐ray photoelectron spectroscopy (XPS), we investigated a number of complexes and macromolecules. We have shown on a large set of UPS, XPS, and DFT data that the calculated Kohn–Sham energies of organic and metalorganic complexes can be used as approximate ionization energies (IEs). It is possible to evaluate IEs with an accuracy of 0.1 eV with the density functional approximation (DFA) defect approach. This method has been successfully tested on a large number of boron β‐diketonates and d‐metal chelate and sandwich complexes. We interpreted the bands in the valence region of the XP spectra of macromolecular organosilicon compounds in the solid state by taking into account the density of states and the ionization cross‐sections. According to DFT calculation results, the one‐electron states in the valence region of the model compounds correlate with the positions of the spectral band maxima. © 2015 Wiley Periodicals, Inc.

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Section: Methodsmentioning

confidence: 99%

Section: Macromolecular Octavinylsilsesquioxane and Octaphenylsilsesqmentioning

confidence: 99%

Application of DFT for the modeling of the valence region photoelectron spectra of boron and d‐element complexes and macromolecules

Osmushko

Vovna

Tikhonov

et al. 2015

Int J of Quantum Chemistry

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“…4 For in stance, the acidic hy dro ly sis of (CH2=CH)Si(OEt)3 leads to Si 8 O 12 (CH=CH 2 ) 8 , 5 in which the 8 branch-end vi nyl groups are equiv a lently at tached to the rigid core, each Si posi tion be ing mimic to a cor ner Si-atom of sil ica sur face.…”

Section: Introductionmentioning

confidence: 99%

Octasilsesquioxane Chemistry I. Attachment of Four Surface Bridges to Octasilsesquioxane Quasi‐cube Framework

Liu

Chu

Slanina

et al. 2002

J Chinese Chemical Soc

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The Pt/C cat a lyzed hydrosilylation of Si8O12(CH=CH2)8 and 8 equiv of HSiMe2Cl pro duced Si8O12(CH2CH2SiMe2Cl)8 that was de-hydrochlorinated with 4 equiv of Z-HOCH2CH2=CHCH2OH in the pres ence of ex cess TMEDA. This prep a ra tion re sulted in the at tach ment of four sur face bridges (-CH 2 CH 2 SiMe 2 OCH 2 CH=CHCH 2 OSiMe 2 CH 2 CH 2 -Z-) on the quasi-cube Si 8 O 12 frame work. As a par al lel study, the the o ret i cal cal cu la tions of Si8O12(-CH2CH2SiH2OCH2CH=CHCH2OSiH2CH2CH2-Z-)4 were carried out at PM3 semi-empirical level to find op ti mized ge om e tries for use in four sub se quent ab in itio com puta tions us ing stan dard ba sis sets of 3-2lG* and 6-31G*. The cal cu la tions sug gest that one should ex pect about equimolar mix ture of the tetra-adducts pro duced by the bridg ing over the edges of the quasi-cube, ei ther over four par al lel edges or over two or thogo nal pairs of par al lel edges, but not by bridg ing across the faces of the quasi-cube. IN TRO DUC TIONPoly he dral oligomeric silsesquioxanes with a gen eral for mula (RSiO3/2)n have a pre cisely de fined in or ganic core, where R maybe hy dro gen, or ganic or in or ganic sub stitu ents, and n is an even num ber greater than 4. They are top o log ically ideal in the prep a ra tion of in ti mate nanocomposite ma te ri als.1 With a quasi-cube shape sil ica core, 2,3 the beststudied octasilsesquioxanes Si 8 O 12 R 8 are com monly ob tained in the hydrolytic polycondensation of RSiCl3 or RSi(OEt)3. 4 For in stance, the acidic hy dro ly sis of (CH2=CH)Si(OEt)3 leads to Si 8 O 12 (CH=CH 2 ) 8 , 5 in which the 8 branch-end vi nyl groups are equiv a lently at tached to the rigid core, each Si posi tion be ing mimic to a cor ner Si-atom of sil ica sur face.With an elec tron-withdrawing sil ica core, the selfmetathesis of Si8O12 (CH=CH2) and Ph sub stitu ents or the for ma tion of metallacyclobutanes con tain ing two ad ja cent Si8O12 frame works. In ad di tion to the large steric en ergy, Si8O12(CH=CH2)8 has the most densely pop u lated ter mi nal olefins on its surface. It is surely of in ter est to build mul ti ple rings on the Si8O12 frame work, mak ing use of the vinylic func tions for chem i cal elab o ra tion. This re port deals with the cal cu la tions of Si8O12(-CH2CH2SiH2OCH2CH=CHCH2OSiH2CH2CH2-Z-)4 1, and the ex per i men tal prep a ra tion of Si8O12 (-CH2CH2-SiMe 2 OCH 2 CH=CHCH 2 OSiMe 2 CH 2 CH 2 -Z-) 4 2, each be ing with 4 macrocyclic rings based on Si8O12 quasi-cage. As the cen tral Si8O12 quasi-cage is looped with four chains, structural iso mers (e.g., 1a, 1b, and 1c, vide in fra) arise, that are com puted in or der to clar ify the rel a tive energetics. Cage com pounds have fre quently been com puted 10 as spe cies of fo cused in ter est of both ex per i ment and the ory. CAL CU LA TIONSAll ge om e try optimizations of 1a, 1b, and 1c were carried out at the PM3 semi-empirical level us ing the Spar tan pro gram pack age.11 The optimizations were per formed with Jour nal of the Chi nese Chem i cal So ci ety, 2002, 49, 943-9...

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“…In 1958, Olsson's group reported their pioneering report of synthesizing VPOSS; after 20 years later, Andrianov and associates presented their investigation on synthesizing VPOSS with a yield of 6% through the hydrolytic polycondensation of vinyltrichlorosilane . The recent effort was utilizing vinyltrichlorosilane as the substrate to produce VPOSS with a significantly improved yield (20–41%); however, the reaction process is very complicated . Therefore, how to develop a new method to synthesize VPOSS with shorter time and higher yield is still a challenge and interesting subject.…”

Section: Introductionmentioning

confidence: 99%

High efficiency synthesis of octavinylsilsesquioxanes and its high performance hybrids based on bismaleimide‐triazine resin

Jiang

et al. 2011

Polymers for Advanced Techs

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An improved method is developed to synthesize octavinylsilsesquioxanes (VPOSS) with shorter time and higher yield, and then VPOSS is used to prepare new hybrids based on bismaleimide‐triazine (BD/CE) resin, coded as VPOSS/BD/CE. The effect of the content of VPOSS on the key properties including curing behavior, thermal, mechanical, and dielectric properties as well as water resistance of VPOSS/BD/CE hybrids were systematically discussed. Compared with BD/CE resin, hybrids show similar curing behavior but different chemical structures and thus macro‐performance. These key properties of hybrids are dependent on the content of VPOSS, all hybrids show significantly improved dielectric properties, water resistance, and dimensional stability; moreover, the hybrids with suitable content of VPOSS have bigger impact strengths. Specifically, with the addition of 7 wt% VPOSS to BD/CE resin, the dielectric constant decreases from 3.7 to 3.2, the dielectric loss decreases 55%, and the coefficient of thermal expansion reduces 23%; moreover, the glass transition temperature and initial decomposition temperature increase about 15°C. The attractive integrated properties suggest that VPOSS/BD/CE hybrids have great potential to be used as structural and functional materials for many cutting‐edge fields. Copyright © 2011 John Wiley & Sons, Ltd.

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Studies of octameric vinylsilasesquioxane by carbon-13 and silicon-29 cross polarization magic angle spinning and inversion recovery cross polarization nuclear magnetic resonance spectroscopy

Cited by 55 publications

References 31 publications

Application of DFT for the modeling of the valence region photoelectron spectra of boron and d‐element complexes and macromolecules

Application of DFT for the modeling of the valence region photoelectron spectra of boron and d‐element complexes and macromolecules

Octasilsesquioxane Chemistry I. Attachment of Four Surface Bridges to Octasilsesquioxane Quasi‐cube Framework

High efficiency synthesis of octavinylsilsesquioxanes and its high performance hybrids based on bismaleimide‐triazine resin

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