Salen ligand

A Salen ligand is a dianionic and tetradendate chelating ligand in a coordination complex. Salen is a contraction for salicylic aldehyde and ethylene diamine which are the reactants for the ligand. The actual composition of the ligand depends on the various substituents. For example Salph is a salen ligand with a Phenyl core group from the imine forming reaction of salicylic aldehyde with o-diaminobenzene.

The chiral version of this ligand has been reported using chiral 1,2-diamine. The salen derived from C2-symmetric 1,2-cyclohexyl diamine and 3,5-Di-tert-butyl salicylaldehdye with different metals (Cr, Mn, Co, Al)has been used for different asymmetric transformation. Eric Jacobsen (Harvard) is famous for using this catalyst for different reactions, see for example the Jacobsen epoxidation.

サレン