The catalytic effect obtained by opening the coordination sphere of the organoactinide complex is presented. Replacing the pentamethylcyclopentadienyl ligand in Cp*2ThCl2 (Cp* = C5Me5) by the bridge ligation [Me2SiCp2″]2- 2[Li]+ (Cp″ = C5Me4) affords the synthesis of ansa-Me2SiCp2″ThCl2, which reacts with two equiv of BuLi affording the corresponding dibutyl complex ansa-Me2SiCp2″Th″Bu2. This latter complex was found to be an active catalyst for the dimerization of terminal alkynes, and in the hydrosilylation of terminal alkynes with PhSiH3. In both processes a large chemoselectivity and regioselectivity are achieved due to the hindered equatorial plane, attributed to the disposition of the methyl groups in the bridge ligation, forcing the incoming substrates to react with a specific regiochemistry.
- Organometall ic complexes