Biplane Ion‐Pairing Induced Supramolecular Assembly for High‐Performance Uranium Detection

Abstract It is still challenging to directly recognize the anionic species [UO2(CO3)3]4−, the dominant species in the environment (82%‐93%), using current optical probes because of the adverse effects of its thick hydration shell on binding interactions. In this study, a water‐soluble Pt(II) methylated terpyridine complex ([Pt(CH3‐tpy)NCO]+) supramolecular probe is designed to directly target [UO2(CO3)3]4− by a new strategy of thick hydration shell overlapping arrangement. The optical response demonstrates excellent selectivity among ≈30 investigated interfering substances, along with rapid response (≈15 s), high sensitivity (64.1 nm) and dual‐signals. It is confirmed both experimentally and theoretically that the superior detection performance is attributed to the formation of a unique supramolecular structure featuring biplane‐like building block, bicolumnar stacking and water‐bridged anionic networks, via the overlap of thick hydration shells of aligned [UO2(CO3)3]4− to boost a superentropic driving force, and the distinguishable dual‐signals arises from the emergence of four types of Pt‐Pt interactions, generating low‐energy metal‐to‐metal charge transfer adsorption/emission. In addition, a [Pt(CH3‐tpy)NCO]+‐based hydrogel platform is constructed for detecting both anionic and cationic uranium, with a detection limit of 14.89 fg. This work unlocks not only a way to directly detect [UO2(CO3)3]4−, but also a new idea for sensing ions with extreme thick hydration layers.