Guest-adaptive molecular sensing in a dynamic 3D covalent organic framework

Molecular recognition is an attractive approach to designing sensitive and selective sensors for volatile organic compounds (VOCs). Although organic macrocycles and cages have been well-developed for recognising organics by their adaptive pockets in liquids, porous solids for gas detection require a deliberate design balancing adaptability and robustness. Here we report a dynamic 3D covalent organic framework (dynaCOF) constructed from an environmentally sensitive fluorophore that can undergo concerted and adaptive structural transitions upon adsorption of gas and vapours. The COF is capable of rapid and reliable detection of various VOCs, even for non-polar hydrocarbon gas under humid conditions. The adaptive guest inclusion amplifies the host-guest interactions and facilitates the differentiation of organic vapours by their polarity and sizes/shapes, and the covalently linked 3D interwoven networks ensure the robustness and coherency of the materials. The present result paves the way for multiplex fluorescence sensing of various VOCs with molecular-specific responses.

Automated summary

The development of porous solids that can rapidly and selectively detect volatile organic compounds (VOCs) is of significant importance in sensor design. In this study, a dynamic 3D covalent organic framework (dynaCOF) was constructed, which can undergo structural transitions upon the adsorption of different gases and vapours. The framework can detect and differentiate organic vapours based on their polarity and sizes/shapes, providing a potential way for multiplex fluorescence sensing of various VOCs.