Regulating aggregation and optical properties of rigid-flexible ligand via metal coordination for multifunctional applications

Abstract

Non-covalent interactions typically drive molecular aggregation, but precisely controlling supramolecular interactions to regulate molecular stacking configurations and expand practical applications remains challenging. Herein, we design and synthesize a rigid-flexible ligand Tpy-Py, incorporating one terpyridine (Tpy) and two pyrenes (Py) moieties. Whose aggregation state is regulated by metal coordination, thereby significantly modulating its optical properties. Tpy-Py exists as monomers in solution and forms excimers in the solid state, with emission shifting from blue to green. Single-crystal analysis reveals that Tpy-Py molecules form H- and J-aggregates via π–π stacking in the crystal, while coordination with Zn²⁺ and Cu²⁺ further tunes the molecular packing, leading to red-shifted emission or quenching. Moreover, the photochromic properties of Tpy-Py are effectively utilized in fingerprint detection, anti-counterfeiting, and visual detection of heavy metal ions. This work provides a new approach for regulating aggregation via non-covalent interactions and highlights the potential of Tpy-Py in multifunctional applications.