SYNTHESIS, CHARACTERIZATION, AND REACTIVITIES OF THE POLYSILOXANE-BRIDGED BINUCLEAR METALLOCENES RAMETHYLDISILOXANEDIYLBIS(CYCLOPENTADIENYLTITANIUM TRICHLORIDE) AND AMETHYLTRISILOXANEDIYLBIS(CYCLOPENTADIENYLTITANIUM TRICHLORIDE)

The reaction of dithallium salts of tetramethyldisiloxanediylbis(cyclo pentadienyl) 3, and hexamethyltrisiloxanediylbis(cyclopentadienyl), 4, with two equivalents of TiCl4 gives the title compounds ramethyldisil oxanediylbis(cyclopentadienyltitanium trichloride), 5 and amethyltrisi loxanediylbis(cyclopentadienyltitanium trichloride), 6 respectively. T he stoichiometric reaction of 5 and 6 with water results in the format ion of new oxygen-bridged metallocenes 2)(mu(2)-O)-(eta(5)-C5H4)(2)-mu (2)-(SiMe(2))(2)O], 7, and [(TiCl2)(2)(mu(2)-O)- (eta(5)-C5H4)(2)-mu(2 )-(SiMe(2))(3)O-2}] 8, In addition, further reaction of 7 and 8 with a nother one equivalent of water or the treatment of 5 and 6 with an exc ess amount of water gives rise to the formation of the metallocene com pounds having Ti4O4 rings [(TiCl)(2)(mu(2)-O)-(eta(5)- C5H4)(2)-mu(2)- (SiMe(2))(2)O](2)(mu(2)-O)(2) 9, and [(TiCl)(2)( 5)-C5H4)(2)-mu(2)-(Si Me(2))(3)O-2](2)(mu(2)-O)(2), 10. All the new kinds of metallocenes pr epared have been characterized by IR, NMR, mass spectrometry, or eleme ntal analysis, Especially an investigation of the de values in H-1 NMR and a comparison between the theoretical and observed isotopic ratio in a mass spectra among the synthesized bridged compounds have been ve ry conveniently utilized to study their structures, Polymerization exp eriments with the dinuclear complexes in the presence of methylalumino xane as a cocatalyst indicate that the compounds 5 and 6 do exhibit ca talytic activity for syndiotactic polymerization of styrene.