Abstract
The catalytic dehydrogenative coupling of secondary silanes has been achieved with the combination of Cp2ZrCl2 and 2 equiv of nBuLi in toluene at 90 °C. The products produced from PhMeSiH2 contain disilane through pentasilanes after 2 days, and longer time periods produce oligomeric mixtures up to the octamer. Disilane through tetrasilane have been isolated as distillable, air-stable liquids and are produced as mixtures of stereoisomers. The distribution of oligomers has been determined under various conditions of temperature, time, solvent, and Si/Zr and Zr/Li ratios as well as with a combination of Cp2ZrCl2 with Grignard reagents. Disilane is formed from Ph2SiH2 even at 110 °C, although silafluorene condenses rapidly even at room temperature to a mixture of oligomers. The combination of Cp2TiCl2/nBuLi with PhMeSiH2 provides oligomers from disilane through hexasilane, whereas Cp2HfCl2 produces disilane and trisilane. A possible mechanism for the coupling reaction is presented.
Original language | English (US) |
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Pages (from-to) | 924-930 |
Number of pages | 7 |
Journal | Organometallics |
Volume | 10 |
Issue number | 4 |
DOIs | |
State | Published - Apr 1 1991 |