Ligand-Tuned Perylene Diimide-Based Versatile Coordination Polymers for Photoluminescent Sensing and Optoelectronics

Chiral self-sorting is essential for the establishment of structures in nature and chemistry. Owing to similarities among recognition sites of enantiomers and shared conformational labilities, high-fidelity chiral self-sorting constitutes a substantial challenge. Coordination polymers (CPs) with a high surface area and chemical tunability have potential applications in luminescent probes and optoelectronics. However, it is difficult to synthesize micro-/nano-scale CPs with high conductivity for optoelectronics. Here, a series of perylene diimide (PDI)-based CPs with large π-planes is synthesized by tuning ligands for use in various sensors. A cadmium (Cd)-based coordination polymer with leucine (LeuPDI-Cd) exhibits a unique chiral self-recognition phenomenon when two enantiomeric ligands are mixed with the metal source because homochiral CPs are thermodynamically more stable than their heterochiral analogs. In addition, photoluminescent (PL) LeuPDI-Cd CPs can detect ethylenediamine with high sensitivity and selectivity. Micro-/nano-sized CPs with methionine (MetPDI-Cd) are used in photodetectors and chemiresistive sensors for the detection of toxic phenylhydrazine. Theoretical calculations reveal that the enhanced conductivity is related to the reduced energy gap, which occurs after adsorption of phenylhydrazine onto the CP surface. These results demonstrate the feasibility and versatility of PDI-based CPs for applications in PL sensing and optoelectronics through the tuning of PDI ligands.