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

## TL;DR

A new three-part system detects zinc ions with high accuracy and speed, offering a better way to monitor zinc in complex environments.

## Contribution

A dual-mode supramolecular system with a three-component assembly for highly specific and fast Zn2+ detection is introduced.

## Key findings

- The system achieves an ultra-low detection limit of 0.199 μM for Zn2+.
- It responds to Zn2+ in less than 3 seconds with high selectivity over other substances.
- The detection mechanism involves Pt-Pt and π-π interactions leading to MMLCT transitions.

## Abstract

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.