Stereocontrolled Self-Assembly of Ln(III)-Pt(II) Heterometallic Cages with Temperature-Dependent Luminescence.

Structurally well-defined discrete d/f heterometallic complexes show diverse application potential in electrooptic and magnetic materials. However, precise control of the component and topology of such heterometallic compounds with fine-tuned photophysical properties is still challenging. Herein, we report the stereocontrolled syntheses of a series of Ln-Pt heterometallic cages through coordination-driven self-assembly of enantiopure alkynylplatinum-based metalloligands (L, L) with lanthanide ions (Ln = Eu, Yb, Nd, Lu). Taking advantage of the metal-to-ligand charge transfer (MLCT) excited state on the designed alkynylplatinum ligands, the excitation window for the sensitized near-infrared (NIR) luminescence on the Yb- and Nd-containing cages can be extended to the visible region (up to 500 nm). Linear temperature-dependent red and NIR emissions observed on the Ln(L) (Ln = Eu and Yb, respectively) complexes suggest their potential applications as luminescent temperature sensors, with sensitivities of -0.54% (Ln = Eu, 77-250 K) and -0.17% (Ln = Yb, 77-300 K) per K achieved. This work not only offers a good strategy to prepare new d/f heterometallic supramolecular cages but also paves the way for the design of stimuli-responsive luminescent materials.