Reactions of (eta(5)-C(5)Me(5))ZrF3, (eta(5)-C(5)Me(4)Et)ZrF3, (eta(5)-C(5)Me(5))(2)ZrF2, (eta(5)-C(5)Me(5))HfF3, and (eta(5)-C(5)Me(5))TaF4 with AlMe(3). Structure of the first hafnium-aluminium-carbon cluster

The reaction of Cp*ZrF3 (1) (Cp* = eta(5)-C(5)Me(5)) and AlMe(3) resulted in the formation of cis-{[Cp*ZrMe(mu(2)-F)][(mu(2)-F)(2)AlMe(2)]}(2) (6) and [(Cp*Zr)(3)Al(6)Me(8)(mu(3)-CH2)(2)(mu(4)-CH)(4)(mu(3)-CH)] (7), respectively. Analogously, (eta(5)-C(5)Me(4)Et)ZrF3 (3) reacts with AlMe(3) in a molar ratio of 1:5 with I methane elimination to give the Zr3Al6C7 cluster of composition {[(eta(5)-C(5)Me(4)Et)Zr](3)Al(6)Me(8)(mu(3)-CH2)(2)(mu(4)-CH)(4)(mu(3)-CH)} (8), which has been characterized by elemental analysis and H-1 NMR and mass spectrometry. Reaction of 2 equiv of AlMe(3) with CP*2ZrF2 (2) leads quantitatively to Cp*(2)ZrMe(2) (12). Reaction of Cp*HfF3 (4) with AlMe(3) in an equimolar ratio gives {[Cp*HfMe (mu(2)-F)][(mu(2)-F)(2)AlMe(2)]}(2) (9) stereospecifically as its cis isomer in high yield. 9 crystallizes in the space group P2(1)/c with four molecules in the elemental cell (Z = 16). From the reaction of 1 equiv of Cp*HfF3 (4) with 3 equiv of AlMe(3), Cp*HfMe(3) (10) can be obtained in a yield of 85%. As a byproduct of this reaction the Hf3Al6C7 cluster [(Cp*Hf)(3)Al(6)Me(8)(mu(3)-CH2)(2)(mu(4)-CH)(4)(mu(3)-CH)] (11) can be isolated in a yield of 5%. The characterization of 11 by single-crystal X-ray diffraction and H-1, C-13 NMR and mass spectroscopic data will be discussed. Cp*TaF4 (5) reacts with a 5-fold excess of AlMe(3), leading quantitatively to Cp*TaMe(4) (13) without further decomposition via C-H activation processes.