Zirconium alkyls with ancillary cyclooctatetraenyl ligands. X-ray crystal structures of [Li(tmed)][(C8H8)Zr(p-C6H4Me)Cl2] and (C8H8)Zr[CH(SiMe3)2

Abstract

Several new group 4 alkyl and aryl compounds have been synthesized that possess ancillary cyclooctatetraene ligands. Most of the complexes isolated are anionic and have stoichiometries of [Li(tmed)2][(C8H8)MRCl2], [Li(tmed)x][(C8H8)MR2Cl], or [Li(tmed)x][(C8H8)MR3], where M = Zr or Hf, and R = Me, Ph, p-Tol, or CH(SiMe3)2. Two neutral 14-electron compounds have also been prepared, (C8H8)M[CH(SiMe3)2]2, where R = Zr or Hf. The compound (C8H8)Zr[CH(SiMe3)2]2 appears to react reversibly with 7 atm of carbon monoxide but does not react with dihydrogen even at 70 atm. IR, 1H and 13C NMR data are reported, along with the crystal structures of two of the new compounds.