Octakis octasilsesquioxan

Neumann and coworkers [6] reported the first synthesis and characterization of a novel POSS, possessing eight isocyanate groups (XVIII) (Scheme 5) via the hydrosilylation of m-isopropenyl-Q ,Q -dimethylbenzyl isocyanate (m-TMI) (XVII) by octakis(dimethylsiloxy)octasilsesquioxane (Q8M8 ) (XVI). 

To sum up, octakis(3-hydroxypropyldimethylsiloxy)octasilsesquioxane (OHPS) has also been synthesized by direct hydrosilylation of allyl alcohol with octakis(dimethylsiloxy)octasilsesquioxane, (HSiMe20)8Si80i2... 

For solid-state Si NMR spectra, other referencing techniques are required. Usually a crystalline organosilicon compound is used (e.g. QgMg , octakis(tri-methylsiloxy)octasilsesquioxane), which gives sharp and intensive Si NMR signals under MAS conditions and H decoupling. Since the 8 Si values of this material are known (—109.3, +11.7) relative to SiMc4, it serves as a reliable secondary reference. 

Summary The synthesis and structure of octakis[4-(trimethylsilylethynyl)phenyl]-octasilsesquioxane (1), the first representative of a new class of octasilsesquioxanes bearing ridid n-conjugated substituents, is described. Furthermore we present the synthesis and structure of octakis(tetracarbonylcobaltio)octasiIsesquioxane (2). In combination with triphenylphosphine, 2 shows catalytic activity in the hydro-formylation of 1-hexene. 

Laine and coworkers have studied a new class of nanocomposites containing multifunctional epoxy-POSS, octakis(glycidyldimethylsiloxy)octasilsesquioxane... 

Synthesis of octakis 3-[(2-hydroxYethYljdimethylammonio]propyl octasiisesquioxane chloride via nucleophilic substitution 148 Synthesis of heptaisobutyl[2- 4-(1-naphthyljphenYl ethenyl]octasilsesquioxane via siiyiative coupiing of monovinylheptaisobutylsilsesquioxane with T(4-vinylphenyl)naphthalene 149... 

Synthesis of Itetrakislf 1,1,2,2,3,3,4,4-octafluoropentyloxypropyl dimethylsiloxy)) tetrakis 3-glycidoxypropyl dimethylsiloxy)octasilsesquioxane via hydrosilylation of allyl-glycidyl ether and 1,1,2,2,3,3,4,4-octafluoropentyl allyl ether with octakis(hydridodimethylsiloxy)octasilsesquioxane 153... 

Synthesis of octakis 3-[(2-hydroxyethyljdimethylammonio]propyl octasilsesquioxane chloride via nucleophilic substitution Reaction Scheme 1 ... 

Octakis 3-chloropropyl)octasilsesquioxane, 2-(dimethylamino) ethanol. Octakis 3-chloropropyl)octasilsesquioxane was prepared according to the procedure described elsewhere (13). 

Octakis(3-chloropropyl)octasilsesquioxane (3 g, 2.7 mmol) and 2-(dimethylamino)ethanol with 100% excess (3.8 g, 4.3 mL, 43 X 10 mol) were placed together in a reaction flask. The reaction was carried out at 100°C for 24 h with stirring. The excess of 2-(dimethylamino)ethanol was removed from the postreaction mixture by vacuum evaporation to give a product as a white solid. 

Octakis(dimethylsiloxy)octasilsesquioxane (5 g, 4.9 x 10 mol), allyl-glycidyl ether (2.3 mL, 19.6 x 10 mol) together with 50 mL of toluene were placed in a three-neck round-hottom flask equipped with thermometer, reflux condenser, heating mantle, and magnetic bar. Next [ Rh(n-OSiMe3)(cod) 2l complex (0.75 mg, 2.5 X 10 mol Rh) was added at room temperature and the solution was heated to 110°C and kept at this temperature for 4 h. After that time, 5-(allyloxy)-l,l,2,2,3,3,4,4-octafluoropentane with 10% excess (6 g, 21.5 x 10 mol) was added and the reaction was carried out for another 4 h. Then the reaction mixture was cooled down and pimfied with column chromatography (silica gel 60/toluene) to remove rhodium complex. Next, the solvent and the excess of olefin were evaporated imder vacuum to give the product as a viscous oil. 

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