- Fast, high-yielding syntheses of silsesquioxanes using acetonitrile as a reactive solvent
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New and efficient methods for the synthesis of cyclopentyl- and cyclohexylsilsesquioxanes are described. In the case of cyclopentylsilsesquioxane, pure trisilanol (c-C5H9J 7-Si7O9(OH)3 was obtained selectively within 18 h in an isolated yield of 64%. The synthesis of cyclohexylsilsesquioxanes also gives high yields, but it is not selective towards a particular structural type [main products: (c-C6H 11)6Si6O9, (c-C6H 11J6Si6O8(OH)2, (c-C 6H11)7Si7O10OH and (c-C6H11)7Si7O9(OH) 3]. We discuss the crucial role of acetonitrile as a reactive solvent in these syntheses. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Pescarmona, Paolo P.,Van Der Waal, Jan C.,Maschmeyer, Thomas
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- Ring opening metathesis polymerization of polyoctahedral oligomeric silsesquioxanes (POSS) incorporated oxanorbornene-5,6-dicarboximide: Synthesis, characterization, and surface morphology of copolymers
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The synthesis and characterization of N-propyl-POSS-7-oxanorbornene-5,6- dicarboximide (NPONDI) and N-3-(trifluoromethyl)phenyl-7-oxanorbornene-5,6- dicarboximide (TFNDI) was reported. The synthesis of the POSS-based (co)polymers were accomplished by ring opening metathesis polymerization (ROMP). The monomers and polymers were characterized using FT-IR, 1H-, 13C-, 29Si-NMR, and GPC techniques. Thermal properties of TFNDI-NPONDI copolymers were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Transmission electron microscopic (TEM) analysis of optically transparent and flexible copolymer films revealed the presence of 50nm-sized POSS agglomerates. Atomic force microscopy analysis of the film surface exhibited a modest increase in surface roughness of TFNDI-NPONDI copolymers as compared with homopoly[N-3(trifluoromethyl)phenyl-7- oxanorbornene-5,6-dicarboximide] (HTFNDI). The POSS incorporated polymers such as 1NPONDI, 2NPONDI, and 3NPONDI increased the hydrophobicity as compared with HTFNDI. This was measured by static contact angle analysis. The study focussed on the dispersion, surface morphology, and the microstructure of POSS in TFNDI-NPONDI copolymer as determined by scanning electron microscopy (SEM). CSIRO 2011.
- Gnanasekaran,Madhavan,Tsibouklis, John,Reddy
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- T8-OSS-ethyldiphenylphosphine: A new functional oligosilsesquioxane ligand
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Oligosilsesquioxanes (OSS) may be considered as molecular sections of silica. The incompletely condensed (cyclopentyl)-T-(OH)3(T=SiO3,2) has been used to generate a phosphine-funetionalized T8-OSS system by reac
- Ruffieux, Vincent,Schmid, Guenter,Braunstein, Pierre,Rose, Jacky
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- Microwave-assisted synthesis of cyclopentyltrisilanol (c-C5H9)7Si7O9(OH)3
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Microwave-assisted synthesis of cyclopentyltrisilanol by the hydrolytic condensation of the cyclopentyltrichlorosilane in aqueous acetone has been successfully performed. The reaction under microwave irradiation is considerably shorter in time in comparison to the traditional procedure and may be utilized for preparation of Si-containing building blocks for nanocomposite materials.
- Janowski, Bart?omiej,Pielichowski, Krzysztof
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- Preparation and reactivity of an O,O-chelating silsesquioxane-palladium complex
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An incompletely condensed silsesquioxane containing trisilanol (c-C 5H9)7Si7O9(OH) 3 reacts with [PdI2(bpy)] (bpy = 2,2′-bipyridine) in the presence of Ag2O to produce a palladium complex with an O,O-chelating silsesquioxanate ligand, [Pd{O11Si7(c-C 5H9)7(OH)}(bpy)] (1). The reaction of Ph 2SiClH with 1 in 2:1 ratio causes disilylations of the silsesquioxanate ligand, forming [PdCl2(bpy)]. Addition of p-cresol to a solution of 1 yields the trisilanol and [Pd(OC6H 4CH3-p)2(bpy)].
- Tanabe, Makoto,Mutou, Kohji,Mintcheva, Neli,Osakada, Kohtaro
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- Mechanistic study of silsesquioxane synthesis by mass spectrometry and in situ ATR FT-IR spectroscopy
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The synthesis of cyclopentylsilsesquioxane a7b3 [(c-C5H9)7Si7O9(OH)3 ] was followed by means of electrospray mass spectrometry (ESI MS) and in situ attenuated total reflection Fourier transform infrared (ATR FTIR) spectroscopy in combination with chemometric analysis methods. This study allowed us to identify silsesquioxane species present in the reaction mixture and to propose a mechanism for the formation of silsesquioxane a7b3. The spectroscopic results proved the existence of short-lived, low molecular weight silsesquioxane precursors and indicated that the final product silsesquioxane a7b3 was only present in very low concentrations in the reaction mixture, suggesting that the high selectivity of the reaction toward silsesquioxane a7b3 is caused by its low solubility.
- Pescarmona, Paolo P.,Raimondi, Maria E.,Tetteh, John,McKay, Ben,Maschmeyer, Thomas
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- Oligomeric silsesquioxanes: Synthesis, characterization and selected applications
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The synthesis, characterization and applications of oligomeric silsesquioxanes were discussed. These were synthesized by hydrolytic condensation of monosilanes. It was observed that high polarity solvents had favourable effect on the synthesis of silsesquioxanes. Another method involving cleavage of Si-O-Si bond of completely condensed silsesquioxanes to synthesize incompletely condensed silsesquioxanes was reported.
- Pescarmona, Paolo P.,Maschmeyer, Thomas
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- Rational design of polyhedral oligomeric silsesquioxane fillers for simultaneous improvements of thermomechanical properties and lowering refractive indices of polymer films
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We describe here the design and synthesis of the polyhedral oligomeric silsesquioxane (POSS)-based dual-functional molecular fillers for simultaneously lowering refractive indices and improving thermomechanical properties of conventional polymers. We prep
- Jeon, Jong-Hwan,Tanaka, Kazuo,Chujo, Yoshiki
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- Organic-inorganic hybrid gels having functionalized silsesquioxanes
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Hybrid terpolymers consisting of polyhedral oligomeric silsesquioxanes (POSS), N,N-dimethylacrylamide, and bipyridine monomer were synthesized by a common radical polymerization method and their structures and thermal properties were studied by FT-IR, 1H NMR, DSC, TGA. The thermal stabilities of the hybrid terpolymers increased on increasing the content of POSS in the feed ratio. New hybrid gels containing POSS were prepared through the coordination of various metal ions to 2,2′-bipyridine-modified hybrid terpolymers. Highly concentrated solutions of terpolymers with iron(II) sulfate or ruthenium(III) chloride gave hybrid gels in good yields. On the other hand, no hybrid gel was formed with nickel(II) chloride even at much higher concentrations of nickel ions due to rapid ligand exchange reactions causing the polymer network to disappear as a result of a change in the nature of the coordination bonds from an intermolecular network to an intramolecular network. The degree of swelling and the thermal stability of the gels in various solvents were dependent on the content of POSS moiety in the hybrid gel and the ruthenium gel was considerably more stable than the iron and nickel gels. The hybrid gels containing POSS had properties characteristic of hydrogels as well as those of lipogel depending on the content of POSS in the hybrid gel. By analysis of the degree of swelling, it was concluded that the amount of POSS moiety in the hybrid gel has a significant effect on the degree of swelling in this system.
- Kim, Kyung-Min,Chujo, Yoshiki
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- Silsesquioxane compound, organic light emitting element, display apparatus, image information processing apparatus, and image forming apparatus
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Provided is an organic light emitting element having high light emitting efficiency. The organic light emitting element includes: an anode; a cathode; an emission layer placed between the anode and the cathode; and a hole transport layer formed between th
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Page/Page column 97; 98
(2017/09/21)
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- Organic-inorganic polymer hybrids using polyoxazoline initiated by functionalized silsesquioxane
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New hybrid polyoxazolines (CubePOZO) were synthesized by ring-opening polymerization of 2-methyl-2-oxazoline initiated by functionalized polyhedral oligomeric silsesquioxane (POSS) with various feed ratios. The hybrid micelles derived from CubePOZO with both seven hydrophobic cyclopentyl groups of POSS and polyoxazoline (POZO) as a hydrophilic segment were prepared in an aqueous phase. Compared to POZO initiated by cyclohexyl iodide or methyl p-toluenesulfonate, increased hydrophobicity caused by the structure of POSS in CubePOZO played a major role in the micelle formation. This depended on the amount of POSS incorporated into the POZO. The CubePOZO100 and CubePOZO200 formed micelles in an aqueous phase with critical micelle concentrations (cmc) of 55 and 100 mg/L, respectively. Transparent polymer hybrids, homogeneous dispersion of hydrophobic POSS bonded covalently to POZO in the silica gel matrix at the molecular level, were obtained through hydrogen-bonding interaction between CubePOZO and silica gel. The obtained polymer hybrids from CubePOZO showed excellent solvent resistance, similar to that of polymer hybrids having an interpenetrating polymer network structure. It was concluded that the solvent-resistant property came from the size of POSS and the hydrophobic interaction between the POSS in the silica gel matrix. In addition, thermal stability of the polymer hybrids from CubePOZO was much increased compared to that of the polymer hybrids from homoPOZO and POSS.
- Kim, Kyung-Min,Keum, Dong-Ki,Chujo, Yoshiki
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p. 867 - 875
(2007/10/03)
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- Silsesquioxanes as ligands for gold clusters
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A new type of gold cluster has been synthesized using the silsesquioxane derivative (cyclopentyl)7Si8O12(CH2) 3SH (T8-OSS-SH) to exchange the PPh3 ligands in (PPh3)12Au55Cl6 by T8-OSS-SH quantitatively. This exchange causes several important changes in the physical and chemical behavior of the compound. Owing to the presence of cyclopentyl substituents, the cluster becomes soluble in non-polar solvents such as pentane. The stability of this compound compared with that of the PPh3-protected cluster is considerably higher meaning that decomposition in solution, and even under the high-energetic irradiation in the microscope, is not observed over longer periods of time. The increase in the total diameter from 2.1 to ca. 4.4 nm is probably responsible for these advantageous properties, supported by strong S-Au bonds. The increase in size is also expressed as an increase in the activation energy for electron-tunneling processes through the ligand shells of neighboring clusters in a densely packed pellet. This increase is from 0.16 eV for (PPh3)12Au55Cl6 to 0.26 eV for the T8-OSS-SH-protected cluster.
- Schmid, Günter,Pugin, Raphael,Malm, Jan-Olle,Bovin, Jan-Olov
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p. 813 - 817
(2007/10/03)
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