Preparation des complexes (M=Ti, Zr; X=Cl, alkyl, aryl, CO). Etude par RMN dynamique de la gene sterique a la rotation des groupements aryle lies au metal

Article abstract of DOI:10.1016/0022-328X(89)85262-3

The new ligand C5Me4H reacts with or to afford the dichloro complexes <(C5Me4H)2MCl2> (M=Ti, Zr) and trichloro complex <(C5Me4H)TiCl3>.Treatment of these complexes with RLi, or their reduction under CO, gives the derivatives <(C5Me4H)2MR2> (R=CH3, C6H5, p-C6H4CH3, CO).The preparation of the new series of compounds, <(C5Me4H)(C5H5)TiR2>, is also described.The electronic effects of the C5Me4H ligand resemble closely those of C5Me5.The coalescence of the 1H and 13C NMR aromatic signals indicates that rotation of the aromatic nucleus around the metal-carbon bond is restricted owing to the large size of the C5Me4H ligand in the aryl complexes.The activation parameters of this rotation have been determined for <(C5Me4H)2Ti(p-C6H4CH3)2>.