223411-76-5Relevant academic research and scientific papers
Triphenylsilanolato complexes of Group 4 metals: Syntheses, X-ray crystal structures and catalytic cyclization reaction of 1,5-hexadiene
Schweder, Bernd,Goerls, Helmar,Walther, Dirk
, p. 14 - 23 (1999)
Complexes of the type [(Ph3SiO)2MCl2(thf)2](toluene) 2 (M=Zr (1), Ti (2), Hf (3)) were prepared from MCl4(thf)2 and two equivalents Ph3SiOLi in thf. In the presence of additional ligands L the compounds [(Ph3SiO)2ZrCl2(L)](tol)n (L=tmen (5), diphos (6), bpy (7)) were isolated. The X-ray structures of 1-3 show in all cases a distorted octahedral coordination around the metals containing the silanolate ligands in cis-positions and the chloride ligands in axial positions. Reaction of solvent-free [(Ph3SiO)2ZrCl2]n (4) with CH3Li in the presence of 2,2′-bipyridine yielded the organometallic compound [(Ph3SiO)2Zr(CH3) 2(bpy)](toluene)2 (8) whose molecular structure has been determined by X-ray crystallography. With an excess of methylalumoxane (MAO) the complexes form Ziegler-Natta catalysts, which convert 1,5-hexadiene into methylenecyclopentane and several dimers depending on the nature of the pre-catalyst and the reaction conditions. The highest rate and selectivity of the catalytic cyclization has been observed when compound 8 acts as the starting complex.
