Lanthanide (Ln3+) luminescence has valuable features including long lifetimes (τ), large effective Stokes shifts, and aversion to photo-bleaching. Sensitization of molecular Ln3+ complexes requires them to have antenna ligands for energy transfer to Laporte forbidden f-f transitions. Reported herein, is a salen type Zn2+ complex with a peripheral binding site for Ln3+ coordination. The ligand was synthesized by condensing 2,3-diaminonapthalene with o-vanillin, which was subsequently metallated with zinc(II) acetate in pyridine. Complexes of various Ln3+ (La3+, Nd3+, Er3+, Yb3+) have been synthesized and characterized by X-ray crystallography. Structures were found to be isotypic with only slight variation in coordination number (CN = 9 - 11) based on Ln3+ size. Electronic absorption displayed two major transitions (λ = 325, 425 nm) that are ligand based; these transitions are conserved through choice of metal and Ln3+ complexes absorb most strongly (ε = ca. 5 x 104). Characteristic near-infrared emission is observed from each complex and quantitative data will be discussed.

Near-infrared emission of heterobimetallic Zn2+/Ln3+ schiff base complexes

2019 Spring National Meeting

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