Dynamic Reconfiguration of Pt(II) Supramolecular Assemblies via Ligand Exchange

Supramolecular chemistry enables molecules to dynamically adapt and reorganize in response to their environment, providing a key route to achieving high levels of structural and functional complexity. This work explores a particular strategy for the dynamic and programmable self-assembly of luminescent platinum(II) complexes via sequential coordination-driven and hierarchical processes. The aggregation behavior and optical properties of square-planar Pt(II) complexes bearing a chromophoric terdentate NNN ligand and exchangeable monodentate ligands are highly dependent on the nature of the ancillary ligand, resulting in morphologically and photophysically distinct supramolecular structures. We demonstrate that these preassembled aggregates undergo dynamic ligand exchange reactions in solution, leading to metastable supramolecular states, including emissive gels, that are accessible exclusively through in situ exchange. Real-time fluorescence microscopy and NMR spectroscopy reveal both homogeneous and heterogeneous exchange pathways, governed by the identity of the initial complex and the incoming ligand. Remarkably, the system exhibits a degree of reversibility and structural memory. These findings establish a framework for stepwise self-assembly that bridges coordination chemistry with noncovalent interactions, offering a versatile platform for designing responsive nanostructures with tailored properties and a step toward adaptive, life-like materials with potential applications in sensing and optoelectronics.