Supramolecular assembly of diplatinum species through weak Pt^II⋅⋅⋅ Pt^II intermolecular interactions: A combined experimental and computational study

The present study elucidates the factors that govern the spontaneous self-assembly of a family of dimetal [Pt₂L₄] (L=dithiocarboxylato ligand) complexes. Experimental data show that variables such as temperature, concentration, solvent and the nature of the ligand L have a critical effect on the reversible self-assembly of supramolecular [Pt₂L₄]n entities. In solution, new UV/Vis spectroscopic features emerge at low temperatures and/or high concentrations, which are attributed to the formation of oligomeric [Pt₂L₄]n species. The description of intermolecular Pt⋅⋅⋅Pt interactions, the main driving force for the association, was addressed from a computational perspective. The contributions from intermolecular Pt⋅⋅⋅S and S⋅⋅⋅S interactions to these supramolecular assemblies were found to be repulsive. Experimental UV/Vis data have been interpreted by means of computational spectroscopy.