The cyclopentadienyl ligand is an important ligand in organometallic chemistry because it will complex a wide range of transition metals. Recently there has been an increased attention to cyclopentadiene ligands containing pendant groups that are capable of coordinating to a metal centre as well. Examples of these bidentate ligands are cyclopentadiene ligands containing amine[2,3], ether, amido[5,6] and alkoxy  pendant groups.
The asymmetric catalytic properties of cyclopentadiene metal complexes are also receiving more attention. Different strategies have been developed to introduce asymmetry in cyclopentadiene metal complexes. Examples of these strategies are the use of cyclopentadiene ligands with a chiral substituent connected to the cyclopentadiene ring , the use of annulated chiral cyclopentadiene ligands [1,10] and the use of ansa-bridged bis-indenyl ligands in which the group bridging the two indenyls is either achiral  or chiral. Chiral cyclopentadiene ligands containing a pendant donor have been described in only a few papers.[4,13] Recently the synthesis of a chiral cyclopentadiene ligand based on ephedrine and pseudo ephedrine was described.
Back to the main page