Dong-Heon Lee

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

Abstract 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 pKa changes of bound H2 are discussed.

Heterolytic dihydrogen activation in an iridium complex with a pendant basic group

Experimental and theoretical studies show that H2 reacts with an Ir phosphine complex having a basic pendant amino group to give either an H2 or an Ir–H···H–N hydrogen-bonded hydride complex, depending on the basicity of the phosphine ligands.

Hydrides and Hydrogen Bonding

Publisher Summary This chapter deals with many metal hydrides. These metal hydrides can be protonated to give dihydrogen complexes. In some cases, kinetic protonation takes place on an M–H bond of a complex to give an M–(H2) complex, even when the thermodynamically most favored protonation site is the metal itself. A combination of theoretical and experimental approaches provides an improved understanding of several aspects of hydride chemistry. A new type of hydrogen bond between a proton and a hydride is shown to influence the properties of a number of main group and transition-metal compounds. It seems to be important in case of protonation of hydrides by acids AH. The chapter also describes Pendant group effects that allow stabilization of an HF complex and observation of heterolytic H2 activation.Publisher Summary This chapter deals with many metal hydrides. These metal hydrides can be protonated to give dihydrogen complexes. In some cases, kinetic protonation takes place on an M–H bond of a complex to give an M–(H2) complex, even when the thermodynamically most favored protonation site is the metal itself. A combination of theoretical and experimental approaches provides an improved understanding of several aspects of hydride chemistry. A new type of hydrogen bond between a proton and a hydride is shown to influence the properties of a number of main group and transition-metal compounds. It seems to be important in case of protonation of hydrides by acids AH. The chapter also describes Pendant group effects that allow stabilization of an HF complex and observation of heterolytic H2 activation.