A unique tetramer of 4:5 beta-cyclodextrin-ferrocene in the solid state

A single crystal of a unique 4:5 inclusion complex between beta-cyclodextrin and ferrocene was prepared and the structure was determined by X-ray crystallographic analysis, showing that four of the five ferrocenes were included in the cavities of four beta-cyclodextrins along the axial orientation of the tetramer, while another was co-included between two beta-cyclodextrins from the equatorial orientation.