Single-site homogeneous and heterogeneized gold(III) hydrogenation catalysts: mechanistic implications.

Au(III)-Schiff base complexes are active hydrogenation catalysts, giving turnover frequencies similar to those of the corresponding complexes of Pd(II), which has the same d8 electronic structure as Au(III). The mechanism of the reaction has been studied in detail by a combination of kinetic experiments and theoretical calculations. It is predicted and tested that the nature of the solvent plays a critical role for the heterolytic cleavage of H2 (controlling step). Taking this into account, and by properly selecting the nature of solid supports (polarity and proton-donating ability), it was possible to strongly increase the activity of the homogeneous Au(III) and Pd(II) catalysts by grafting them onto the surface.

Homogeneous and heterogenized Au(III) Schiff base-complexes as selective and general catalysts for self-coupling of aryl boronic acids.

A series of homogeneous and heterogenized gold metal complexes show high activity and selectivity for the homocoupling of a large variety of aryl boronic acids, being of general utility for the synthesis of C2-symmetric biaryls.