Synthesis and characterization of Zr(IV) and Y(III) complexes with monocyclopentadienyl ligands containing an additional site tethered by a coordinating 2,6-pyridine bridge. X-ray crystal structures of the zirconium complexes

A new monocyclopentadienyl ligand containing an additional site tethered by a coordinating 2,6-pyridine unit has been prepared, rac-2-(1′-hydroxy-2′,2′-dimethylpropyl)-6-(1″,1″-dimethyl-cyclopentadienylmethyl) pyridine dilithium salt, LLi2 (rac-4) that is analogous to the ligands present in CGC. After reacting the dilithium salt of the ligand with ZrCl4 in a molar ratio of 1:1 in THF the complex LZrCl2·THF (rac-5) was obtained which forms an insoluble oligomeric species after the loss of THF upon purification. From the mater liquor two crystalline species of the formula LHZrCl3 (rac-6) and LH2ZrCl4·THF (rac-7) were isolated, whose X-ray crystal structures are reported. The reaction of LLi2 with Y(OTf)3 afforded the probably dimeric species [LYOTf]2 (rac-8) from which the complex [LY(CH2Si(CH3)3)]2 (rac-9) was obtained after reaction with LiCH2Si(CH3)3.