text: In organometallic chemistry, a transition metal indenyl complex is a coordination compound that contains one or more indenyl ligands.  The indenyl ligand is formally the anion derived from deprotonation of indene. The η-indenyl ligand is related to the ηcyclopentadienyl anion (Cp), thus indenyl analogues of many cyclopentadienyl complexes are known.  Indenyl ligands lack the 5-fold symmetry of Cp, so they exhibit more complicated geometries.  Furthermore, some indenyl complexes also exist with only η-bonding mode.  The η- and η-bonding modes sometimes interconvert.