Cyclotetrameric supersandwich structure of a structurally confined C1-bridged dilithiobis(cyclopentadienide): a case of supramolecular LiCp-association

The rigid C1-bridged dilithiobis(cyclopentadienide) exhibits a cyclotetrameric (Li2(Cp-R-Cp))4 supramolecular structure. The Li2 is eta(super 5)-coordinated to the exposed face of the tetrahydroindenyl substrate. The projection of the unit cells reveal that 4*tmeda tetramers form a columnar conformation in the crystal. The arrangement in the compound depends upon the nature of the ligand system. The study uses X-ray diffraction and quantum chemical calculations.