A two-and-a-half-layer sandwich: potassium salt of anionic (η4-tetrasilacyclobutadiene)(η5-cyclopentadienyl)ruthenium

Abstract

An anionic ruthenium sandwich complex featuring the tetrasilacyclobutadiene ligand, [η⁴-tetrakis(di-tert-butylmethylsilyl)tetrasilacyclobutadiene](η⁵-pentamethylcyclopentadienyl)ruthenium was synthesized and isolated as its potassium salt [(η⁴-R₄Si₄)RuCp*]⁻·[K⁺(thf)₂] (R = SiMet-Bu₂, Cp* = η⁵-Me₅C₅), 1⁻·[K⁺(thf)₂], by the reaction of the tetrasilacyclobutadiene dianion dipotassium salt [R₄Si₄]²⁻·[K⁺(thf)₂]₂ with 0.25 equiv. of [Cp*RuCl]₄ in THF. In its crystalline form, 1⁻·[K⁺(thf)₂] features a nearly square-planar tetrasilacyclobutadiene ligand.