Adaptive Pillar[5]arene Co-Crystals Showing Vapochromic Behavior to 5-Membered Heterocyclic Compounds
1Academy of Interdisciplinary Studies on Intelligent Molecules, Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University, Tianjin 300387, P. R. China.
The Journal of Organic Chemistry
|November 13, 2025
Summary
New crystalline materials show selective color changes when exposed to specific vapors. This discovery in supramolecular chemistry could lead to advanced vapor sensors.
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Crystallography
Background:
- Macrocycle-based crystalline materials are explored for solid-state vapor adsorption.
- Pillar[5]arene (P5) and pyromellitic diimide (PDI) derivatives are key components in supramolecular assemblies.
Purpose of the Study:
- To investigate the vapochromic properties of binary adaptive co-crystals formed from P5 and PDI.
- To understand the structural basis for selective vapor detection.
Main Methods:
- Synthesis and characterization of P5-PDIα co-crystals.
- Exposure to various vapors and observation of color changes.
- Powder and single-crystal X-ray diffraction to analyze structural transformations.
- Evaluation of thin film performance for vapor sensing.
Main Results:
- P5-PDIα co-crystals exhibit selective vapochromism towards 5-membered heterocyclic compounds (5-MHCs).
- Color transitions from white to yellow/orange are observed upon vapor exposure.
- Vapor-induced structural rearrangements lead to the formation of charge-transfer (CT) cocrystals.
- Spin-coated thin films demonstrate reversible and stable vapochromic sensing.
Conclusions:
- The P5-PDI system offers a novel platform for selective vapor detection based on solid-state structural changes.
- The observed vapochromism is driven by the formation of charge-transfer interactions within the crystal lattice.
- The material's performance in thin-film form highlights its potential for practical sensor applications.
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