With silsesquioxane core

Star-like PFs 236 with a silsesquioxane core have been prepared by Ni-mediated copolymerization of 2,7-dibromo-9,9-dioctylfluorene with octa(2-(4-bromophenyl)ethyl)octasilses-quioxane [333]. The polymer is thermally stable up to 424°C (TGA). In both chloroform solution and films, its absorption and PL spectra are very close to that for PFO 196, although a somewhat higher PL efficiency is observed in films (64 and 55%, respectively). The polymer 236, however, demonstrates a better PL color stability during thermal annealing. An ITO/PEDOT/236/Ca/Ag device can be turned on at 6.0 V, and shows a brightness of 5430 cd/m2 (at 8.8 V) with F] =0.44%, almost twice as high as that for the corresponding PFO device (Chart 2.60). 

This approach has also been employed for synthesis of highly enan-tiomerically enriched cychc silanes with sihcon-centered chirahty [141]. Zhang et al. [142] prepared second-generation dendrimers based on polyhedral silsesquioxane cores with up to 72 terminal groups at their surface (Scheme 13). 

Crivello, J.V. Malik, R. Synthesis and photoini-tiated cationic polymerization of monomers with the silsesquioxane core. J. Polym. Sci. Polym. Chem. 1997, 35, 407. 

The PDMAEMA stars are weak cationic polyelectrolytes. But they can be easily transformed into strong cationic polyelectrolytes poly [2-(methacryloyloxy)ethyl] trimethylammonium iodide] (PMETAI) stars by quaternization with methyl iodide. Asymmetric field flow fractionation (AFFF) measurements showed that the silsesquioxane core remained intact. The PMETAI brushes were also subjected to... 

A carbosilane dendrimer decorated with Ru(bpy)3 units has been prepared and electrochemical studies reported. " " Newkome has reported first-generation stars with surface polyoxometallate decoration. " A silsesquioxane core has been functionalized and a series of dendritic systems bearing Frechet-type dendritic wedges and pendant Ru(tpy)(bpy)2 decoration has been described. Up to 32 of these units containing didentate tpy ligands have been attached to the surface. ... 

The synthesis and properties of star polymers and dendrimers functionalized with ferrocene units has attracted a great deal of attention. The synthesis of high-generation dendrimers functionalized with chiral ferrocenyl units in their structures has been reported. The chiroptical properties of this class of dendrimer was dependent on the number of ferrocenyl groups and their chemical environment, but not on their position within the dendrimer. Deschenaux has reported the synthesis of hquid crystalline ferrocene-based polymers prossessing an enantiotropic smectic A phase. Ferrocene-functionahzed cyclic siloxane (29) and silsesquioxane branched polymers have also been reported. A hyperbranched polymer with a cubic silsesquioxane core was used to mediate the electrocatalytic oxidation of ascorbic acid. 

A series of octafunctional epoxy and 1-propenyl ether monomers bearing the Tg silsesquioxane core have been prepared and characterized. Despite the high functionality and reactivity of these monomers, the efficiency with which the monomers undergo crosslinking is considerably less than expected. Instead, due to steric inhibition effects and the proximity of the functional groups to one another, photoinduced cationic polymerization proceeds mainly by an intramolecular process. 

Polymers and Higher Order Structures with Cage Oligomeric Silsesquioxane Core. 208... 

The first silsesquioxane derivative of copper was made in our laboratory according to Scheme 65. The reaction of the monosilylated disilanol precursor 12 with tetrameric copper(I)-r-butoxide in a molar ratio of 2 1 afforded the colorless copper(I) silsesquioxane complex 187, in which the CU4O4 core of copper(I)-t-but-oxide is retained. 

Ethylene oxide/propylene oxide triblock copolymers have been successfully used to template pore formation in ultra low-k films, and dielectric constants as low as 1.5 have been observed with polymer loading levels of 50 wt% (5). These films have good mechanical properties, a high breakdown voltage and a low moisture uptake. We have characterized the films with high-resolution solid-state proton NMR and found that the triblock copolymers form nm-sized core-shell structures with the propylene oxide block at the interface between the ethylene oxide block and the methyl silsesquioxane matrix (14). 

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