the (R) enantiomer. The re face will simply hit the chiral fence. Note that when the ligand is replaced by its mirror image the other enantiomer will form and that a racemic mixture of ligand will once again yield a racemic product. Also note that if the steric bulk of both carbonyl substituents is very similar the strategy will fail. Other C2-symmetric complexes Many C2-symmetric complexes are known. Some arise not from C2-symmetric ligands, but from the orientation or disposition of high symmetry ligands within the coordination sphere of the metal. Notably, EDTA and triethylenetetraamine form complexes that are C2-symmetric by virtue of the way the ligands wrap around the metal centers. Two isomers are possible for (indenyl)2MX2, Cs- and C2-symmetric. The C2-symmetric complexes are optically stable. Asymmetric ligands Ligands containing atomic chirality centers such asymmetric carbon, which usually do not have C2-symmetry, remain important in catalysis. Examples include cinchona alkaloids and certain phosphoramidites. P-chiral monophosphines have also been investigated. See also Chiral anion catalysis Further reading References Coordination chemistry Stereochemistry Organometallic chemistry Ligands