Dual Emission with Efficient Phosphorescence Promoted by Intermolecular Halogen Interactions in Luminescent Tetranuclear Zinc(II) Clusters
Fumiya Kobayashi, Yuta Takatsu, Daisuke Saito, Masaki Yoshida, Masako Kato, Makoto Tadokoro
Abstract
High Resolution Image Download MS PowerPoint Slide The development of Zn-based phosphorescent materials, associated with a ligand-centered (LC) transition, is extremely limited. Herein, we demonstrated dual emissions including fluorescence and phosphorescence in luminescent tetranuclear Zn(II) clusters [Zn 4 L I 4 (μ 3 -OMe) 2 X 2 ] ( HL I = methyl-5-iode-3-methoxysalicylate; X = I, Br, Cl), incorporating iodine-substituted ligands. Single-crystal X-ray structural analyses and variable-temperature emission spectra studies revealed the presence of iodine substitutions, and intermolecular halogen interactions produced the internal/external heavy-atom effects and yielded strong green phosphorescence with a long emission lifetime (λ max = 510–522 nm, Φ em = 0.28–0.47, τ av = 0.78–0.95 ms, at 77 K). This work provided a new example that the introduction of halogen interactions is an advantageous approach for inducing phosphorescence in fluorescent metal complexes.