Efficient and reversible luminescence detection for CO2 without solvent assistance is of great significance but still remains challenging to achieve, due to the lack of efficient interaction between CO2 molecules and the host emitting center. Benefiting from the abundant host-guest interactions, metal clusters provide a platform for detecting small molecules. However, the insufficient chemical stability of most metal clusters limits the practical applications. Here, we report a hydrophobic Cu(I) cluster (denoted as CuIDPO) with one-dimensional channels. Notably, it displays exceptional chemical stability in both acidic and alkaline aqueous solutions (pH = 1-14). More importantly, CuIDPO shows remarkable CO2-induced luminescence enhancement (up to 385% in 1 bar CO2), which can be applied to analyze CO2 content (LOD = 7.7 mbar). Crystallographic analysis and theoretical calculations suggest the mechanism of CO2-locking rotation of the phenyl groups in the Cu(I) cluster through guest-host π‒π interaction, which is quite unique when compared to the known acid-base neutralization and framework flexibility adjustment mechanisms. Such luminescence CO2 sensing shows advantages like ultrafast response and well reversibility. Additionally, CuIDPO-loaded membranes were fabricated for spatially resolved 2D visual detection.
