Crystal structure of the formal 20 electron zirconocene penta-fulvene complex Cp2Zr(η5,η1-adamantyl-idene-penta-fulvene):toluene:n-hexane = 1:0.125:0.125

The crystal structure of a solvated zirconocene penta-fulvene complex with a bulky adamantyl-idene substitution pattern, namely (η5,η1-adamantyl-idene-penta-fulvene)bis-(η5-cyclo-penta-dien-yl)zirconium(IV)-toluene-n-hexane (8/1/1), [Zr(C15H18)(C5H5)2]·0.125C7H8·0.125C6H14, is reported. Reducing zirconocene dichloride with magnesium results in the formation of a low-valent zirconocene reagent that reacts readily with adamantyl-idene-penta-fulvene to give the aforementioned complex. Single crystal X-ray diffraction proves the dianion-like η5:η1 binding mode of the fulvene ligand to the central ZrIV atom. The asymmetric unit contains four independent mol-ecules of [η5:η1-adamantyl-idene-penta-fulvene]bis-[(η5)-cyclo-penta-dien-yl]zirconium(IV), together with half a mol-ecule of toluene disordered with half a mol-ecule of n-hexane (the solvent mol-ecules have no direct influence on the complex). In each of the four complex mol-ecules, the central ZrIV atom has a distorted tetra-hedral coordination environment. The measured crystal consisted of two domains with a refined ratio of 0.77:0.23.

Crystal structures of titanium-aluminium and -gallium complexes bearing two μ2 -CH3 units

The isotypic crystal structures of two titanocene complexes containing an EMe3 unit (E = Al, Ga; Me = meth-yl) with two μ2-coordinating methyl groups, namely [μ-1(η5)-(adamantan-1-yl-2κC1)cycylo-penta-dien-yl]di-μ2-methyl-methyl-2κC-[1(η5)-penta-methyl-cyclo-penta-dien-yl]aluminiumtitanium(III), [AlTi(CH3)3(C10H15)(C15H18)], and [μ-1(η5)-(adamantan-1-yl-2κC1)cycylo-penta-dien-yl]di-μ2-methyl-methyl-2κC-[1(η5)-penta-methyl-cyclo-penta-dien-yl]galliumtitanium(III), [GaTi(CH3)3(C10H15)(C15H18)], are reported. Reacting a dinuclear nitro-gen-bridged low-valent titanium(III) complex with the Lewis acids AlMe3 or GaMe3 results in the loss of mol-ecular di-nitro-gen and the formation of two monomeric titanocene(III) fragments bearing two μ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a new E-C bond involving the penta-fulvene ligand while the bridging and terminal methyl groups remain intact.