Synthesis, Characterization, and Catalytic Activity of Gold Complexes Bearing Bicyclic Silicon and Germanium Anionic Ligands

Silanides ([R₃Si^–]) and germanides ([R₃Ge^–]) are attracting attention as donor ligands for transition metals, but their use as supporting ligands in catalysis is limited, often due to their high reactivity. In this study, we report the preparation and characterization of gold(I) complexes bearing the anionic silanide and germanide ligands tmimSi^– and tmimGe^– (tmimH₃ = tris(3-methylindol-2-yl)methane), which are stabilized by a bicyclic cage structure. Both the silanide and germanide complexes catalyze the hydroamination of 1-ethynyl-4-fluorobenzene with aniline. The germanide complexes are more efficient than their silanide analogues, likely due to their more electrophilic character. These results show that both ligand types can be used as supporting ligands in catalysis, which warrants further investigations.