Synthese, Aufbau und Eigenschaften käfigartiger vinyl- und allylsilylierter Kieselsäuren

By silylation of tetramethylammonium silicate (Pu'(CH,),),Si,O,, . 69 H,O with vinyldimethylehlorosilane (I) and divinyltetramethyldisiloxane, respectively, or allyldimethylchloro - silane there were synthesized the crystalline silicic esters (CH,=CH(CHz),Si),Si,0,, and (CH,=CH-- CH,(CH,),Si),Si,O,,. By means of gas chromatography, mass spectrometry, lH and 29Si NMR the two compounds were identified to be cage-like double four-ring(D4R-)silicic esters containing right vinyldimethylsilyl- or allyldimethylsilyl groups. Silylation with a mixture of I and trimethylchlorosilane yields in dependence on the ratio of silanes vinyldimethylsilyltrimethylsilyl DZR silicic esters with average numbers of unsaturated groups t8.