Crystal structure of the formal 20 electron zirconocene pentafulvene complex Cp 2 Zr( 5, 1-adamantylidenepentafulvene):toluene: N-hexane = 1:0.125:0.125

The crystal structure of a solvated zirconocene pentafulvene complex with a bulky adamantylidene substitution pattern, namely ( 5, 1-adamantylidenepentafulvene)bis( 5-cyclopentadienyl)zirconium(IV)-toluene-n-hexane (8/1/1), [Zr(C 15 H 18)(C 5 H 5) 2 ]0.125C 7 H 8 0.125C 6 H 14, is reported. Reducing zirconocene dichloride with magnesium results in the formation of a low-valent zirconocene reagent that reacts readily with adamantylidenepentafulvene to give the aforementioned complex. Single crystal X-ray diffraction proves the dianion-like 5: 1 binding mode of the fulvene ligand to the central Zr IV atom. The asymmetric unit contains four independent molecules of [ 5: 1-adamantylidenepentafulvene]bis[( 5)-cyclopentadienyl]zirconium(IV), together with half a molecule of toluene disordered with half a molecule of n-hexane (the solvent molecules have no direct influence on the complex). In each of the four complex molecules, the central Zr IV atom has a distorted tetrahedral coordination environment. The measured crystal consisted of two domains with a refined ratio of 0.77:0.23.