What is "hemilability"

In coordination chemistry and catalysis hemilability ( hemi - half, lability - a susceptibility to change) refers to a property of many polydentate ligands which contain at least two electronically different coordinating groups, such as hard and soft donors. These hybrid or heteroditopic ligands form complexes where one coordinating group is easily displaced from the metal centre while the other group remains firmly bound; a behaviour which has been found to increase the reactivity of catalysts when compared to the use of more traditional ligands.