Substrate binding and activation via pendant hydrogen-bonding groups as an approach to biomimetic homogeneous catalysis

In a biomimetic approach to organometallic catalysis, pendant hydrogen-bonding groups are shown to influence the chemistry of ligand binding and activation in an iridium complex. Such groups can bind a substrate by hydrogen bonding and so offer the possibility of a biomimetic approach to catalysis where binding is controlled via molecular recognition. Because catalyst design in this area may be challenging, combinatorial and rapid screening methods may be needed to assay potential catalysts and initial progress on developing these methods for hydrosilation of alkenes and imines is described. Catalysis of aldehyde imination and the origin of pK_a changes of bound H₂ are discussed.