Reactions of (η⁵-C₅Me₅)ZrF₃, (η⁵-C₅Me₄Et)ZrF₃, (η⁵-C₅Me₅)₂ZrF₂, (η⁵-C₅Me₅)HfF₃, and (η⁵-C₅Me₅)TaF₄ with AlMe₃. Structure of the First Hafnium−Aluminum−Carbon Cluster

The reaction of Cp*ZrF 3 ( 1 ) (Cp* = η 5 -C 5 Me 5 ) and AlMe 3 resulted in the formation of cis -{[Cp*ZrMe(μ 2 -F)][(μ 2 -F) 2 AlMe 2 ]} 2 ( 6 ) and [(Cp*Zr) 3 Al 6 Me 8 (μ 3 -CH 2 ) 2 (μ 4 -CH) 4 (μ 3 -CH)] ( 7 ), respectively. Analogously, (η 5 -C 5 Me 4 Et)ZrF 3 ( 3 ) reacts with AlMe 3 in a molar ratio of 1:5 with methane elimination to give the Zr 3 Al 6 C 7 cluster of composition {[(η 5 -C 5 Me 4 Et)Zr] 3 Al 6 Me 8 (μ 3 -CH 2 ) 2 (μ 4 -CH) 4 (μ 3 -CH)} ( 8 ), which has been characterized by elemental analysis and 1 H NMR and mass spectrometry. Reaction of 2 equiv of AlMe 3 with Cp* 2 ZrF 2 ( 2 ) leads quantitatively to Cp* 2 ZrMe 2 ( 12 ). Reaction of Cp*HfF 3 ( 4 ) with AlMe 3 in an equimolar ratio gives {[Cp*HfMe (μ 2 -F)][(μ 2 -F) 2 AlMe 2 ]} 2 ( 9 ) stereospecifically as its cis isomer in high yield. 9 crystallizes in the space group P 2 1 / c with four molecules in the elemental cell ( Z = 16). From the reaction of 1 equiv of Cp*HfF 3 ( 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 Hf 3 Al 6 C 7 cluster [(Cp*Hf) 3 Al 6 Me 8 (μ 3 -CH 2 ) 2 (μ 4 -CH) 4 (μ 3 -CH)] ( 11 ) can be isolated in a yield of 5%. The characterization of 11 by single-crystal X-ray diffraction and 1 H, 13 C NMR and mass spectroscopic data will be discussed. Cp*TaF 4 ( 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.