Yingjie Li, Yali Hou, Shijin Jian, Haonan Peng*, Zhaohui Wang*, and Mingming Zhang*. J. Phys. Chem. B 2026, 130, 10609-10618. DOI: 10.1021/acs.jpcb.6c04747

Coordination-driven self-assembly has emerged as a powerful strategy for the construction of discrete supramolecular coordination complexes with well-defined geometries and topologies. Perylene diimide (PDI) derivatives are especially attractive fluorescent building blocks; accordingly, PDI-based metallacycles have shown significant potential in fluorescence sensing, particularly for picric acid (PA). However, the systematic construction of homologous fluorescent metallacycles with progressively increasing topological complexity through multicomponent self-assembly remains largely underexplored.

Herein, by simply varying the geometry and connectivity of auxiliary carboxylate ligands, discrete monocyclic, bicyclic, and tricyclic PDI metallacycles were controllably assembled and confirmed by NMR, ESI-MS, and single-crystal X-ray diffraction. 4d adopts a three-dimensional tricyclic architecture with a distorted, partially enclosed cavity. All four remain highly emissive, and 4d displays a pronounced donor–acceptor electronic structure. PA induced progressive quenching with topology-dependent LODs of 4.1, 5.2, 3.2, and 2.3 μmol/L; 4d shows the highest sensitivity via a static association-assisted quenching mechanism.

In summary, topological engineering through multicomponent heteroleptic self-assembly provides an effective strategy for tuning the electronic properties and sensing performance of discrete coordination architectures.

Figure 1. Single-crystal structures of PDI-based metallacycles 4a–4d

Figure 2. Absorption and emission spectra and frontier molecular orbital calculations of the metallacycles

Figure 3. Fluorescence sensing response of metallacycle 4d toward picric acid and investigation of the sensing mechanism

First Author: Li Yingjie, doctoral candidate, Shaanxi Normal University

Correspondence Authors: Prof. Peng Haonan, Shaanxi Normal University; Prof. Zhang Mingming, Xi’an Jiaotong University; Prof. Wang Zhaohui, Tsinghua University

Full Text Link: https://doi.org/10.1021/acs.jpcb.6c04747