Disilene R*XSi=SiXR* (R*=SitBu3) mit siliciumgebundenen H- und Hal-Atomen X: Bildung, Isomerisierung, Reaktionen

摘要: Abstract Dehalogenations of 1,2-disupersilyldisilanes R*H2SiSiHalHR*, R*HHalSiSiHalHR*, R*HHalSiSiHal2R* and R*Hal2SiSiHal2R* in THF with equimolar amounts supersilyl sodium NaR* (R*=SitBu3=Supersilyl) lead slowly at room temperature (Hal=Cl) or fast even −78°C (Hal=Br, I) under exchange one halogen Hal for Na to yellow–orange disilanides R*H2SiSiNaHR*, R*HHalSiSiNaHR*, R*HHalSiSiNaHalR* R*Hal2SiSiNaHalR* (identification by protonation, methylation, silylation). These then, the latter three cases, eliminate NaHal formation trans-1,2-disupersilyldisilenes R*XSiSiXR* silicon-bound H atoms as X. Actually produced are R*HSiSiHR*, R*HSiSiBrR*, R*ClSiSiClR*, R*BrSiSiBrR* R*ISiSiIR*. The intermediate existence disilenes could be proved trapping them diphenylacetylene (formation [2+2] cycloadducts), anthracene [4+2] benzophenone and/or 2,3-dimethylbutadiene cycloadducts well ene reaction products). Obviously, isomerization R*HalSiSiHalR* silylenes R*Hal2SiSiR* is possible, which may trapped Et3SiH. In absence mentioned traps, R*HSiSiHR* thermolizes cyclotrisilanes R*3Si3H3 R*3Si3H2R R=SiH2R* cyclotetrasilanes R*4Si4H4, whereas R*HSiSiBrR* react an unidentified mixture substances. disilene R*ClSiSiClR* forms presence its source R*Cl2SiSiNaClR* R*4Si4Cl4 obviously way insertion into SiNa bond followed elimination NaCl. Finally, R*ISiSiIR* goes over cyclotrisilane R*3Si3I2R R=SiI2R*, take place [2+1] cycloaddition isomer R*I2SiSiR*. NaR*, endo,exo- endo,endo-bicyclotetrasilanes R*4Si4H2. Thereby, pure endo,endo transforms equilibrium endo,exo mole ratio 1:9 (the reactions R*4Si4H2 I2 R*3Si3HIR R=SiHIR* R*4Si4H2I2). On other hand, (Hal=Cl, Br, quantitatively transform, possibly via disilenides R*HalSiSiNaR* cyclotetrasilenes R*4Si4Hal2, tetrahedrotetrasilane R*4Si4 tetrahedrane reacts O2, I2, R*4Si4O2, R*4Si4I2, R*4Si4Na2). X-ray structure analyses presented cis,cis,trans-R*4Si4H2I2 cis,trans,cis-R*4Si4Cl4 Ph2CO CH2CMeCMeCH2.