The structural diversity triggered by intermolecular interactions between Au(I)S2 groups: aurophilia and beyond

Abstract

The present study is aimed at elucidating the factors that direct the assembly of a specific family of Au(I) species. The assembly of Au(I) centers and dithiocarboxylato or xanthato ligands results in a surprising structural diversity observed by single-crystal X-ray diffraction. However, in solution, just evidences for discrete bimetallic [Au(2)L(2)] species have been observed. Interestingly, when dithiocarboxylato ligands have been used, a reversible supramolecular assembly has been observed forming the supramolecules of formulae [Au(2)L(2)](2) and [Au(2)L(2)](3). Initial studies on luminescent properties have been carried out at variable temperature. All the compounds show red emissions in the solid state at very similar energies, suggesting that the intramolecular interactions play a more relevant role in the luminescent properties than the intermolecular ones. The computational studies indicate that not only Au···Au interactions, but also Au···S and S···S ones play a role in the structure and energetic of the supramolecular species, as well as for the choice between supramolecular association or intramolecular oligomerization.