Structural studies of lanthanide ion complexes of pure gold, pure silver and mixed metal (gold–silver) dicyanides

Abstract

Crystal structures of four lanthanide complexes of La[Au(CN)₂]₃·3H₂O, La[Ag(CN)₂]₃·3H₂O, La[Ag_0.83Au_0.17(CN)₂]₃·3H₂O, and La[Ag_0.39Au_0.61(CN)₂]₃·3H₂O are reported. Studies reveal that all the structures reported are isostructural. All systems were found to be in the hexagonal crystal system, space group P6₃/mcm. The metal–metal distance for the pure gold system is 3.332 (1) Å versus 3.359(1) Å for the pure silver system. The mixed-metal systems have shown no distinct differences in the location of the metal atoms, with the La[Ag_0.83Au_0.17(CN)₂]₃·3H₂O complex having a metal–metal Ag–Au separation of 3.346(1) Å, and 3.344(1) Å for the La[Ag_0.39Au_0.61(CN)₂]₃·3H₂O complex. The crystal structures of the pure and mixed La complexes have been solved to provide evidence of Ag–Au heterometallic interactions and as a basis for understanding the interesting optical properties of the systems.