Synthesis of a pentasilapropellane. Exploring the nature of a stretched silicon-silicon bond in a nonclassical molecule.
We report on the successful synthesis of Si(5)Mes(6) (Mes = 2,4,6-trimethylphenyl), which consists of an archetypal [1.1.1] cluster core featuring two ligand-free, "inverted tetrahedral" bridgehead silicon atoms. The separation between the bridgehead Si atoms is much longer, and the bond strength much weaker, than usually observed for a regular Si-Si single bond. A detailed analysis of the electronic characteristics of Si(5)Mes(6) reveals a low-lying excited triplet state, indicative of some biradical(oid) character. Reactivity studies provide evidence for both closed-shell and radical-type reactivity, confirming the unusual nature of the stretched silicon-silicon bond in this "nonclassical" molecule.
Nied
Dominik
D
Faculty of Chemistry and Biosciences, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe, Germany.
Köppe
Ralf
R
Klopper
Wim
W
Schnöckel
Hansgeorg
H
Breher
Frank
F