Synthesis and crystal structure of a new lanthanide cyclooctatetraene complex (η8-C8H8)Er(µ-η8-C8H8)K(µ-η8-C8H8)Er(µ-η8-C8H8)K(THF)4

Abstract
The tetranuclear nearly-linear complex (η8-C8H8)Er(µ-η8-C8H8)K(µ-η8-C8H8)Er(µ-η8-C8H8)K(THF)4(THF = tetrahydrofuran) is first synthesised by the reaction of benzylcyclopentadienyl erbium dichloride (PhCH2C5H4)ErCl2·3THF with cyclooctatetraenyl potassium K2C8H8 in 1 : 1 molar ratio in THF; a single crystal X-ray study has shown that the complex has the tetralayer-sandwich structure and that the adjacent Er3+ and K+ ions are bridged by η8-cyclooctatetraenyl group.