Structural characterization of potassium salts of the decamethylmanganocene anion Cp*2Mn−†
For the first time the crystal structure of a permethylated metallocene anion has been obtained. The 17 valence electron complex decamethylmanganocene Cp*2Mn is reduced by molten potassium in THF to its extremely air-sensitive anion [Cp*2Mn]−. The potassium salt [K(THF)2]+[Cp*2Mn]− crystallizes upon cooling from hot THF and forms infinite polymeric chains exhibiting strong K⋯C contacts. In the presence of 18-crown-6 the polymeric structure is broken up. Crystals of [K(18-crown-6)(THF)2]+[Cp*2Mn]− were obtained upon slow cooling from THF to −80 °C displaying well separated cations and anions.