P-H FUNCTIONAL ZIRCONOCENE-PHOSPHIDO COMPLEXES - SYNTHESIS OF CP2ZR(PH(2,4,6-TBU3C6H2))(X) (CP=C5H5, X=CL, PH(2,4,6-TBU3C6H2)) AND MOLECULAR-STRUCTURE OF CP2ZR(PH(2,4,6-TBU3C6H2))2

The reaction of Cp2ZrCl2 (Cp = C5H5) with solvent-free LiPH(2,4,6-tBu3C6H2) yields the terminal zirconocene phosphido complexes Cp2Zr(Cl){PH(2,4,6-tBu3C6H2)) (1) (1:1 reaction) or Cp2Zr{PH(2,4,6-tBu3C6H2)}2 (2) (1:2 reaction). 2 is more readily obtained from the reaction of Cp2ZrCl2 With H2P(2,4,6-tBu3C6H2) in the presence of Mg. 1 and 2 were characterized spectroscopically (NMR, IR, MS). An X-ray structure determination of 2 shows that the Zr-P bond lengths (Zr-P1 2.681(5) angstrom, Zr-P2 2.682(5) angstrom) are identical. 1 and 2 exhibit dynamic NMR behaviour (H-1) indicating rotation around the P-C bond and inversion of the phosphido group.