Tunable Luminescent Heterometallic Zn2Ln2 Edge-Defective Molecular Cubane with Stimuli-Responsive Properties.

Heterometallic Zn2Ln2 [Ln = Gd (1), Eu (2), Tb (3), Dy (4)] discrete molecules with edge-defective cubane structure are assembled from a multifunctional fluorescent conjugate ligand and LnIII/ZnII mixed-metal ions; they exhibit the tunable luminescence, including ligand-based yellow-green light emission for 1 and 4 and lanthanide-center emission for 2 and 3. The multiple stimuli-responsive photoluminescences were investigated to show a two-step thermal-responsive luminescence increase in the intensity upon cooling and piezochromic luminescence.