Gas detection by structural variations of fluorescent guest molecules in a flexible porous coordination polymer

The development of a new methodology for visualizing and detecting gases is imperative for various applications. Here, we report a novel strategy in which gas molecules are detected by signals from a reporter guest that can read out a host structural transformation. A composite between a flexible porous coordination polymer and fluorescent reporter distyrylbenzene (DSB) selectively adsorbed CO 2 over other atmospheric gases. This adsorption induced a host transformation, which was accompanied by conformational variations of the included DSB. This read-out process resulted in a critical change in DSB fluorescence at a specific threshold pressure. The composite shows different fluorescence responses to CO 2 and acetylene, compounds that have similar physicochemical properties. Our system showed, for the first time, that fluorescent molecules can detect gases without any chemical interaction or energy transfer. The host–guest coupled transformations play a pivotal role in converting the gas adsorption events into detectable output signals. Methodologies capable of directly visualizing and detecting gases are important for a wide variety of applications that involve instantaneous decision-making in complex environments and locations. A strategy for the capture and detection of gases by co-operative structural transformations of a flexible porous coordination polymer and fluorescent reporter molecules is now reported.