Novel bicyclic Si-ring systems

Abstract Two diphenylated bicyclic silanes bi(3-phenyldecamethylcyclohexasilanyl) and bi(4-phenyldecamethylcyclohexasilanyl) were synthesized by action of Na/K alloy on the mixed substituted monocycles 1-chloro-3-phenyl- or 1-chloro-4-phenyldecamethylcyclohexasilane. UV absorption spectra are reported compared with the spectra of ( cyclo -Si 6 Me 11 ) 2 and its monophenylated derivatives. Reaction of the di-Grignard reagent BrMg C 6 H 4 MgBr with chloroundecamethylcyclohexasilane ( cyclo -Si 6 Me 11 )Cl and bromononaphenylcyclopentasilane ( cyclo -Si 5 Ph 9 )Br afforded the 1,4-bis(cyclosilanyl) substituted benzene derivatives 1,4-bis(undecamethylcyclohexasilanyl)benzene ( cyclo -Si 6 Me 11 ) 2 C 6 H 4 and 1,4-bis(nonaphenylcyclopentasilanyl)benzene ( cyclo -Si 5 Ph 9 ) 2 C 6 H 4 . Both were investigated by 29 Si CP/MAS NMR. The single crystal structure and the cyclic voltammogram of ( cyclo -Si 6 Me 11 ) 2 C 6 H 4 are reported.