present a highly efficient method for the synthesis of functionalized silsesquioxanes mediated by scandium(III) triflate, which opens up the possibility of introducing a wide variety of functional groups into this class of organosilicon compounds under mild conditions with excellent yields. We also investigated the differences in the activity of the Lewisacid (Sc(OTf)3) and the hidden Brønsted acid (TfOH)
Proton-conducting electrolyte film of double-decker-shaped polyhedral silsesquioxane containing covalently bonded phosphonic acid groups
作者:Asuman C. Kucuk、Jun Matsui、Tokuji Miyashita
DOI:10.1039/c2jm15779a
日期:——
As described in this paper, phosphonic-acid-containing double-decker-shaped polyhedral silsesquioxane (PHOS-DDSQ) was synthesized and the proton conductivity of the PHOS-DDSQ cast film was studied under humid and non-humid conditions. To synthesize PHOS-DDSQ, double-decker-shaped polyhedral silsesquioxane (DDSQ) was initially reacted with di(ethylene glycol) (DEG) vinyl ether using hydrosilylation reaction to attach four DEG units to one DDSQ (4DEG-DDSQ). Subsequently, a phosphate esterification of hydroxyl groups in 4DEG-DDSQ was carried out using POCl3. NMR, XPS, and MALDI-TOF MS spectra and titration measurements revealed that the phosphate esterification connected two DEG units to form a crown-ether-like structure. This structure prevents hydrolysis of the phosphate ester bond. PHOS-DDSQ showed high thermal stability, with decomposition temperature exceeding 220 °C, because of its inorganic DDSQ core. A uniform film of PHOS-DDSQ can be fabricated by drop casting. The cast film showed high proton conductivity (0.12 S cm−1) under humid conditions, which is comparable to that of a Nafion® membrane. Moreover, the cast film offered good proton conductivity under non-humid conditions (3.6 × 10−4 S cm−1 at 170 °C). The conductivity and thermal stability indicate that PHOS-DDSQ is a good candidate for use as a proton-conductive membrane in hydrated type fuel cells as well as fuel cells operated at intermediate temperatures (100–200 °C) under non-humid conditions.
A Highly Effective Route to Si−O−Si Moieties through
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‐Silylation of Silanols and Polyhedral Oligomeric Silsesquioxane Silanols with Disilazanes
作者:Krzysztof Kuciński、Grzegorz Hreczycho
DOI:10.1002/cssc.201802757
日期:2019.3.7
A simple and highly practical catalyst‐free O‐silylation of silanols with commercially available disilazanes has been developed under mild conditions. In the case of polyhedral oligomeric silsesquioxane (POSS) silanols and some other silanols, it was necessary to usecatalyticamounts of inexpensive Bi(OTf)3 as additional catalyst. This efficient chlorine‐free protocol involves the synthesis of a wide
An organic–inorganic hybrid amorphous molecular material; carbazole-substituted double-decker-shaped silsesquioxane (DDSQ-4Cz) was synthesized, and an organic light-emitting diode was fabricated using the spin-coated DDSQ-4Cz film as a hole transport layer.