Exploring the Reactivity of Perphenylheptasilanes: Synthesis of Terminally Functionalized Derivatives

A series of 1,7‐disubstituted tetradecaphenylheptasilanes was synthesized to prepare model compounds for terminally functionalized perphenylpolysilanes. Starting from perphenylheptasilane Ph‐(SiPh 2 ) 7 ‐Ph, two phenyl groups were substituted with triflate. The resulting triflated heptasilane TfO‐(SiPh 2 ) 7 ‐OTf was then reacted with alkali metal halides to produce the 1,7‐dihalogenides X‐(SiPh 2 ) 7 ‐X (where X = F, Cl, Br, I). Additionally, an alternative synthetic route to the chlorine derivative was developed by reacting Li‐(SiPh 2 ) 5 ‐Li with Cl 2 SiPh 2 , a method that had previously only been briefly mentioned in the literature. All products were subsequently reacted with LiAlH 4 , and in the case of the triflate compound with ( i Bu) 2 AlH, to obtain the 1,7‐dihydrogen derivative H‐(SiPh 2 ) 7 ‐H. Nearly complete conversion to the hydride was observed, except when fluorine or chlorine substituted heptasilanes were used. The compounds were analyzed using IR‐, Raman‐, 29 Si‐, 19 F‐, and 1 H‐NMR spectroscopy, as well as melting point determination. Single crystal structure analyses of H‐(SiPh 2 ) 7 ‐H, Br‐(SiPh 2 ) 7 ‐Br, and I‐(SiPh 2 ) 7 ‐I were performed, supporting the presented results.