Hierarchical Assemblies of Unsymmetric Pt Complexes with Ag Ions: Two Types of Assembly Modes Depending on the Remote Ancillary Groups in the Bridging Ligands

Self-assembly via noncovalent interactions can amplify small structural differences in small molecular units, producing large supramolecular architectures with structure-dependent complexity and characteristics. In this paper, the unique self-assembly behaviors of mononuclear Pt(II) complex units accommodating Ag(I) ions are reported. The Pt complex with the N^C chelating ligand and two different kinds of pyrazole ligands gave two regioisomers, whose structural difference was only the position of the N and C donor atoms in the N^C chelating ligands. This small structural difference influences the assembled structures with Ag ions, producing two different types of heteropolynuclear complexes with different clustering motifs. This was further amplified via a hierarchical assembly process incorporating additional Ag ions to afford two different types of Pt-Ag cluster-of-cluster complexes. This study proves that the self-assembly of unsymmetrical fragments can endow significant complexity and perturbation in molecular systems, enabling the observation of unique molecular behaviors.