ETA(6)-ARENE DERIVATIVES OF TITANIUM(IV), ZIRCONIUM(IV) AND HAFNIUM(IV)

The structure of the ionic product [Ti(eta(6)-Me(6)C(6))Cl-3]AlCl4 I h as been determined by an X-ray diffraction experiment: orthorhombic; a = 12.890(4), b = 8.609(2), c = 9.168(3) Angstrom; V = 1017.4(6) Angst rom(3), Z = 2; d(calc) = 1.584 g cm(-3). Tetrachlorogallates of titani um(IV) of general formula [Ti(eta(6)-arene)Cl-3]GaCl4 (arene = 1,2,4,5 -Me(4)C(6)H(2), Me(6)C(6)), have been obtained by reaction of TiCl4 wi th the appropriate arene in the presence of GaCl3 in toluene, Formatio n of complexes with less methyl-substituted arene ligands (MeC(6)H(5), 1,4-Me(2)C(6)H(4) and 1,3,5-Me(3)C(6)H(3)) has been established by C- 13-NMR spectroscopy. The MCl(4)/Me(6)C(6)/benzene system gives, either in the presence or in the absence of aluminium trichloride, covalent (M = Zr) or ionic (M = Hf) compounds of Formula Zr(eta(6)-Me(6)C(6))Cl -2(mu-Cl)(3)ZrCl3 4 and [Hf(eta(6)-Me(6)C(6))Cl-3]Hf2Cl9 5. Compounds 4 and 5 have been Fully characterized by conventional methods includin g X-ray crystallography, Compound 5: orthorhombic; a = 17.662(6), b = 8.960(3), c = 17.683(6) Angstrom; V = 2798.4(16) Angstrom(3), Z = 4; d (calc) = 2.666 g cm(-3).