Synthesis and characterization of 2-pyridylalkoxide complexes of titanium,zirconium and tantalum. Crystal structures of TiCp*Me-2(OCMePy2) and TaCp*Cl-3(OCPy3) (Cp* = eta(5)-C5Me5, Py = C5H4N)

The methyltitanium derivative TiCp*Me-3 (Cp*=eta(5)-C5Me5) reacted with tri s(2-pyridyl)methyl alcohol, HOCPy3, to yield the alkoxide complex TiCp*Me-2 (OCPy3) 1. The reaction of TiCp*Me-3 with di-2-pyridyl ketone, Py2CO, yield ed, through an insertion process, the corresponding alkoxide derivative TiC p*Me-2(OCMePy2) 2. In order to establish the co-ordination mode of the alko xide ligand, X-ray diffraction studies were carried out on complex 2. Inser tion of di-2-pyridyl ketone into a Ta-Me bond of TaCp*Me-4 gave the corresp onding alkoxide compound TaCp*Me-3(OCMePy2) (3). Metathesis reaction of tit anium and zirconium complexes MCp*Cl-3 with the lithium alkoxide LiOCRPy2 l ed to the corresponding derivatives MCp*Cl-2(OCRPy2) [M=Ti, R=Me (4) or Py (5); M=Zr, R=Me (6) or Py (7)]. In an analogous way, tantalum derivatives T aCp*Cl-3(OCRPy2) [R=Me (8) or Py (9)] can also be synthesized by reaction o f TaCp*Cl-4 with the appropriate lithium alkoxide LiOCRPy2. The crystal str ucture of complex 9 has been determined by X-ray diffraction.