PREPARATION AND CHEMICAL BEHAVIOUR OF HALOCYCLOPENTADIENYL-ZIRCONIUM(III) AND -HAFNIUM(III)

Article abstract of DOI:10.1016/0022-328X(85)80246-1

Reduction of (η⁵-C5H5)2MCl2 (M=Zr, Hf) with one equivalent of Na/Hg gives <(η⁵-C5H5)2M(μ-Cl)>2.The zirconium(III) complex is also obtained from reactions between LiCp and 2>2 (L₂=2P-n-Bu3, dppe) or solutions of ZrCl4 previously reduced with Na/Hg.These zirconium(III) and hafnium(III) complexes are oxidized by AgBF4 or TlBF4 to the cationic <(η⁵-C5H5)2M(μ-Cl)>2²⁺ complexes, which react with monodentate ligands to give <(η⁵-C5H5)MClL>⁺ (L=OPPh3, NHPh2) and with bidentate ligands to give dinuclear cationic derivatives<<(η⁵-C5H5)2MCl>2(μ-L-L)>²⁺ (L-L-dppe, 2,2'-bipyridine).Similar complexes can also be obtained from (η⁵-C5H5)2MCl2 by halide abstraction with a silver salt.Oxidation of zirconium(III) and hafnium(III) derivatives with halogens gives (η⁵-C5H5)MClX (X=Cl, Br) and <(η⁵-C5H5)2ZrCl(OPPh3)>I3.Conductivity, magnetic susceptibility and IR and NMR data are discussed.