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

Abstract

The reaction of Cp*ZrF3 (1) (Cp* = η5-C5Me5) and AlMe3 resulted in the formation of cis-{[Cp*ZrMe(μ2-F)][(μ2-F)2AlMe2]}2 (6) and [(Cp*Zr)3Al6Me8(μ3-CH2)2(μ4-CH)4(μ3-CH)] (7), respectively. Analogously, (η5-C5Me4Et)ZrF3 (3) reacts with AlMe3 in a molar ratio of 1:5 with methane elimination to give the Zr3Al6C7 cluster of composition {[(η5-C5Me4Et)Zr]3Al6Me8(μ3-CH2)2(μ4-CH)4(μ3-CH)} (8), which has been characterized by elemental analysis and 1H NMR and mass spectrometry. Reaction of 2 equiv of AlMe3 with Cp*2ZrF2 (2) leads quantitatively to Cp*2ZrMe2 (12). Reaction of Cp*HfF3 (4) with AlMe3 in an equimolar ratio gives {[Cp*HfMe (μ2-F)][(μ2-F)2AlMe2]}2 (9) stereospecifically as its cis isomer in high yield. 9 crystallizes in the space group P21/c with four molecules in the elemental cell (Z = 16). From the reaction of 1 equiv of Cp*HfF3 (4) with 3 equiv of AlMe3, Cp*HfMe3 (10) can be obtained in a yield of 85%. As a byproduct of this reaction the Hf3Al6C7 cluster [(Cp*Hf)3Al6Me8(μ3-CH2)2(μ4-CH)4(μ3-CH)] (11)...