(2,5‐Bis{[(2,6‐diisopropylphenyl)imino]methyl}pyrrolyl)yttrium and ‐lutetium Complexes – Synthesis and Structures

The reaction of 2,5‐bis{[(2,6‐diisopropylphenyl)imino]methyl}pyrrole (dip 2 ‐pyr)H with n BuLi and KH resulted in the lithium compound [(dip 2 ‐pyr)Li] and the potassium compound [(dip 2 ‐pyr)K], respectively. Transmetallation of [(dip 2 ‐pyr)Li] with YCl 3 in thf afforded the “ate complex” [(dip 2 ‐pyr)YCl 3 Li(thf) 3 ], in which an additional equivalent of LiCl is coordinated as a four‐membered Li–Cl–Y–Cl metallacycle. In contrast, treatment of [(dip 2 ‐pyr)K] with anhydrous yttrium and lutetium trichloride resulted in [(dip 2 ‐pyr)LnCl 2 (thf) 2 ] (Ln = Y, Lu). Obviously, by using the potassium reagent [(dip 2 ‐pyr)K] the formation of “ate complexes” is inhibited. Reaction of NaC 5 H 5 with [(dip 2 ‐pyr)YCl 3 Li(thf) 3 ] or [(dip 2 ‐pyr)YCl 2 (thf) 2 ] afforded the metallocene [(dip 2 ‐pyr)Y(η 5 ‐C 5 H 5 ) 2 ]. A significant difference in reactivity between the compounds [(dip 2 ‐pyr)YCl 3 Li(thf) 3 ] and [(dip 2 ‐pyr)YCl 2 (thf) 2 ] could not be observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)