The strong organoborane Lewis acid B(C6F5)(3) catalyzes the polymerization of phenylsilane at elevated temperatures forming benzene and SiH4 as side-products. The resulting polymer is a branched polysilane with an irregular substitution pattern, as revealed by 2D NMR spectroscopy. Having explored the mechanism of this novel metal-free polymerization by computational chemistry methods at the DFT level, we have suggested that unusual cationic active species, namely monomer-stabilized silyl cations, propagate the polymerization. Hydride abstraction of SiH3 moiety by the catalyst in the initiation step was found to be kinetically preferred by around 9kcalmol(-1) over activation by coordination of the monomer at the aromatic ring. The formation of linear SiSi bonds during propagation was calculated to be less favorable than branching and ligand scrambling, which accounts for the branched and highly substituted form of the polymer that was obtained. This novel type of polymerization bears the potential for further optimization with respect to degree of polymerization and structure control for both primary as well as secondary silanes, which can be polymerized by sterically less hindered boranes.     «

The strong organoborane Lewis acid B(C6F5)(3) catalyzes the polymerization of phenylsilane at elevated temperatures forming benzene and SiH4 as side-products. The resulting polymer is a branched polysilane with an irregular substitution pattern, as revealed by 2D NMR spectroscopy. Having explored the mechanism of this novel metal-free polymerization by computational chemistry methods at the DFT level, we have suggested that unusual cationic active species, namely monomer-stabilized silyl cations...     »

ISI Document Delivery No.: 209CH Times Cited: 0 Cited Reference Count: 79 Feigl, Andreas Chiorescu, Ion Deller, Katrin Heidsieck, Sven U. H. Buchner, Magnus R. Karttunen, Virve Bockholt, Andreas Genest, Alexander Roesch, Notker Rieger, Bernhard Wacker Chemie AG; Fonds der Chemischen Industrie This work was supported by Wacker Chemie AG and Fonds der Chemischen Industrie (N.R., B.R.). We gratefully acknowledge a generous allotment of computing resources by Leibniz Rechenzentrum Munchen. 0 Wiley-v c h verlag gmbh Weinheim     «

ISI Document Delivery No.: 209CH Times Cited: 0 Cited Reference Count: 79 Feigl, Andreas Chiorescu, Ion Deller, Katrin Heidsieck, Sven U. H. Buchner, Magnus R. Karttunen, Virve Bockholt, Andreas Genest, Alexander Roesch, Notker Rieger, Bernhard Wacker Chemie AG; Fonds der Chemischen Industrie This work was supported by Wacker Chemie AG and Fonds der Chemischen Industrie (N.R., B.R.). We gratefully acknowledge a generous allotment of computing resources by Leibniz Rechenzentrum Munchen. 0 Wiley-...     »