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Updated: Dec 11, 2025
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Macrocycle Co-Crystals Showing Vapochromism to Haloalkanes
Bin Li1,2, Lei Cui1, Chunju Li1,2
1College of Science, Center for Supramolecular Chemistry and Catalysis, Shanghai University, Shanghai, 200444, P. R. China.
Abstract:
Organic co-crystal engineering is a promising method to make multifunctional materials. Here, the marriage of macrocyclic chemistry and co-crystal engineering provides a smart strategy to build vapochromic materials. The macrocycle co-crystals (MCCs) were constructed from π-electron rich pillar[5]arene (P5) and an electron-deficient pyromellitic diimide derivative (PDI) on a 10 g scale. MCCs of P5-PDI are in red owing to the formation of a charge-transfer (CT) complex. After solvent removal, a white crystalline solid with a new structure (P5-PDIα) is yielded, which exhibits selective vapochromic responses to volatile organic compounds (VOCs) of haloalkanes, accompanied by color changes from white to red or orange. Powder and single-crystal X-ray diffraction analyses reveal that the color changes are attributed to the vapor-triggered solid-state structural transformation to form CT co-crystals. Coating films of P5 and PDI on glass showed a visible vapochromic behavior with good reversibility.
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