Abstract

A 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.1

Reference:

1. Yeung, J. Y.-W.; Kong, F. K.-W.; Hau, F. K.-W.; Chan, M. H.-Y.; Ng, M.; Leung, M.-Y.; Yam, V. W.-W. Angew. Chem. Int. Ed. 2022, 61, e202207313; Angew. Chem. 2022, 134, e202207313