A recyclable polyoxometalate-based supramolecular chemosensor for efficient detection of carbon dioxide

A new type of supramolecular chemosensor based on the polyoxometalate (POM) Na₉DyW₁₀O₃₆ (DyW₁₀) and the block copolymer poly(ethylene oxide-b-N,N-dimethylaminoethyl methacrylate) (PEO₁₁₄-b-PDMAEMA₁₆) is reported. By taking advantage of the CO₂ sensitivity of PDMAEMA blocks to protonate the neutral tertiary amino groups, CO₂ can induce the electrostatic coassembly of anionic DyW₁₀ with protonated PDMAEMA blocks, and consequently trigger the luminescence chromism of DyW₁₀ due to the change in the microenvironment of Dy³⁺. The hybrid complex in dilute aqueous solution is very sensitive to CO₂ content and shows rapid responsiveness in luminescence. The luminescence intensity of the DyW₁₀/PEO-b-PDMAEMA complex increases linearly with an increasing amount of dissolved CO₂, which permits the qualitative and quantitative detection of CO₂. The complex solution also shows good selectivity for CO₂, with good interference tolerance of CO, N₂, HCl, H₂O and SO₂. The supramolecular chemosensor can be recycled through disassembly of the hybrid complex by simply purging with inert gases to remove CO₂.