Solvent‐Dependent Supramolecular Host–Guest Assemblies of Platinum(II) Tweezers and a Guest System: From Discrete Molecules to High‐Ordered Oligomers

Abstract

AbstractA series of platinum(II) calix[4]arene‐based molecular tweezers was synthesized. The studies of the host–guest association with a charge‐neutral cyclometalated platinum(II) complex showed a drastic color change and the turning on of near‐infrared emission resulting from Pt⋅⋅⋅Pt and π–π interactions. Control of the host–guest assembly process by varying the solvent composition can lead to a change from discrete host and guest molecules to high‐ordered host–guest oligomers with the formation of sheet‐like nanostructures, demonstrating a rare example of three‐state supramolecular host–guest system with high solubility in solvents of diverse polarity. The change in host–guest assembly behaviors could be probed by drastic color changes from yellow to orange to green. The present study provides insights into the systematic design of solvent‐responsive molecular materials using molecular tweezers‐directed host–guest assembly, with potential applications in colorimetric sensing of changes in the micro‐environment.