Multiresponsive Cyclometalated Crown Ether Bearing a Platinum(II) Metal Center

Abstract

Multiresponsive materials can adapt to numerous changes in their local environment, which makes them highly valuable for various applications. Although nanostructured and polymeric multiresponsive materials are plentiful, small-molecule analogues are scarce. This work presents a compact cyclometalated platinum(II) complex that bears a crown ether cavity (<b>18C6</b>-Pt^II); the intimate ring/emitter connectivity is key to unlocking multiresponsiveness. Complex <b>18C6</b>-Pt^II responds to (i) cationic guests, producing changes in luminescence in both solution and the solid state, (ii) solvent molecules, which perturb the packing of the complex in the solid state and cause reversible color changes, and (iii) solvent polarity, which leads to controlled aggregation. These responses may enable <b>18C6</b>-Pt^II to function as a sensor for ions and solvents, or as a functional unit for the fabrication of hybrid supramolecular polymers and metallogels.