Unique Three-Component Supramolecular Assembly for Highly Specific Detection of Zinc Ions

The detection of zinc ions plays an essential role in protecting public health and maintaining ecological balance. However, traditional fluorescent probes for Zn²⁺ are limited in their specificity, especially under complex environments, due to their single-mode optical signal and inadequate recognization capacities. Herein we report a dual-mode supramolecular sensing system constructed from a unique three-component assembly involving a terpyridine platinum (II) complex, oxalate, and Zn²⁺, enabling highly specific detection performance for Zn²⁺. The supramolecular sensing system exhibits excellent selectivity among various interfering substances, accompanied by ultra-low detection limit (0.199 μM) and fast response (<3 s). The high recognization capacity comes from tri-component-based supramolecular assembly, while the dual-mode response arises from the generation of intermelcular Pt-Pt and π-π interactions, which yields absorption and emission originating from low-energy metal-metal-to-ligand charge transfer (MMLCT) transitions. This work marks a pioneering demonstration for highly specific detection of Zn²⁺ and inspires an alternative strategy for designing cation probes.