η6-Arene derivatives of titanium(IV), zirconium(IV) and hafnium(IV)

Article abstract of DOI:10.1016/0022-328X(96)06194-3

The structure of the ionic product [Ti(η⁶-Me₆C₆)Cl₃]AlCl₄ 1 has been determined by an X-ray diffraction experiment: orthorhombic; a = 12.890(4), b = 8.609(2), c = 9.168(3) A; V= 1017.4(6) A³, Z = 2; d_calc = 1.584 g cm^-3. Tetrachlorogallates of titanium(IV) of general formula [Ti(η⁶-arene)Cl₃]GaCl₄ (arene = 1,2,4,5-Me₄C₆H₂, Me₆C₆), have been obtained by reaction of TiCl₄ with the appropriate arene in the presence of GaCl₃ in toluene. Formation of complexes with less methyl-substituted arene ligands (MeC₆H₅, l,4-Me₂C₆H₄ and 1,3,5-Me₃C₆H₃) has been established by ¹³C-NMR spectroscopy. The MCl₄/Me₆C₆/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(η⁶-Me₆C₆)Cl₂(μ-Cl)₃ZrCl₃ 4 and [Hf(η⁶-Me₆C₆)Cl₃]Hf₂Cl₉ 5. Compounds 4 and 5 have been fully characterized by conventional methods including X-ray crystallography. Compound 5: orthorhombic; a = 17.662(6), b= 8.960(3), c= 17.683(6) A; V = 2798.4(16) A³, Z =4; d _calc = 2.666 g cm^-3.