(DIPHENYLPHOSPHINO)METHYL COMPLEXES OF TITANIUM AND ZIRCONIUM - SYNTHESIS AND CHARACTERIZATION - MOLECULAR-STRUCTURE OF CPCP-STAR-TI(CH2PPH2)2 (CP = C5H5, CP-STAR = C5ME5)

The reaction of [C5(CH3)5](C5H5)MCl2 (M = Ti, Zr) with 2 equiv of LiCH2PPh2.TMEDA offers a convenient method for the preparation of the corresponding dialkyl derivatives [C5(CH3)5](C5H5)M(CH2PPh2)2 where M = Ti and Zr in 95-100% yield. However, when this reaction is carried out with 1 equiv of LiCH2PPh2.TMEDA in the same conditions, the chloro alkyl complex of titanium [C5(CH3)5](C5H5)TiCl(CH2PPh2) is formed, whereas a mixture of the starting material and the dialkyl derivative is obtained for zirconium. These new complexes have been characterized by H-1, C-13, and P-31{H-1} NMR measurements and elemental analysis. The H-1 NMR spectra show a clear diastereotopic behavior for the methylene protons of the CH2 groups. The molecular structure of [C5(CH3)5](C5H5)Ti(CH2PPh2)2 as determined by X-ray diffraction methods is reported. The complex crystallizes in the space group P2(1)/c (No. 14), a = 17.323 (2) angstrom, b = 12.549 (1) angstrom, c = 16.497 (2) angstrom, beta = 103.71 (2)-degrees, Z = 4. The geometry around the Ti atom is normal. A weak agostic interaction Ti...H(4) can be proposed to be present in the structure of the solid state of this compound.