Ion exchange in bimetallic cage organosiloxanes incorporating copper and alkali metal atoms

The globular metallic cage organosiloxanes [RSiO₂]₁₂[Cu₄M₄] (where R=Me, CH₂=CH or Ph and M=Na or K) can be converted to the corresponding alkaline Li derivatives in an ion-exchange reaction with LiCl under mild conditions (in up to 79% yields). The [RSiO₂]₁₂Cu₄Li₄ compounds have been synthesised and their structures have been studied by X-ray diffraction analysis.