Subtle adjustments for constructing multi-nuclear luminescent lanthanide organic polyhedra with triazole-based chelates

Controlled self-assembly of predetermined multi-nuclear lanthanide organic polyhedra (LOPs) still presents a challenge, primarily due to the unpredictable coordination numbers and labile coordination geometries of lanthanide ions. In this study, through introducing triazole-based chelates to increase the chelating angle of C 2 -symmetric linear ligands and stabilize the coordination geometry of Eu( iii ) centers, M 4 L 6 -type (M = Eu III , L = ligand) tetrahedra were efficiently synthesized, especially a biphenyl-bridged ligand which is well known to form M 2 L 3 -type helicates. A series of LOPs were formed and characterized by high-resolution electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS) and X-ray crystallography. Moreover, the europium complexes exhibit bright emission (luminescence quantum yield up to 42.4%) and circularly polarized luminescence properties (| g lum | up to 4.5 × 10 −2 ). This study provides a feasible strategy for constructing multi-nuclear luminescent LOPs towards potential applications. Subtle chelating arm tweaks facilitate controlled high-nuclear LOP synthesis and enhance lanthanide ion luminescence, offering a unique construction method.