A Series of Lanthanide-Based Metal-Organic Frameworks: Synthesis, Structures, and Multicolor Tuning of Single Component

The single component (SC) white-light emitting (WLE) metal-organic frameworks based on europium (Eu-MOFs), which could be applied in lighting and display, have drawn great attention but have rarely been exploited. In this work, we dedicated to design and synthesize SC-WLE Eu-MOFs via a dichromatic strategy on the balance of simultaneous ligand-based and Eu-based emissions. The Eu-MOF {[Eu₄(obb)₆(H₂O)₉]·(H₂O)}_∞ (IAM16-3) generated via the self-assembly of the flexible ligand 4,4′-oxybisbenzoic acid (H₂obb) and europium ions displays fascinating excitation-wavelength-dependent photoluminescence (EWDP) property. Upon different excitation wavelengths, tunable WLE through manipulating the intensity ratio of characteristic emissions of Eu³⁺ ions and ligand-based emissions was performed. To the best of our knowledge, this is the first example for Eu-MOFs to yield SC-WLE stemming from EWDP property. Three isomorphic lanthanide-based MOFs (LnMOFs), that is, {[Ln₄(obb)₆(H₂O)₉]·(H₂O)}_∞ (Eu³⁺: IAM16-3; Tb³⁺: IAM16-4; Dy³⁺: IAM16-5) based on the flexible bridging linker, that is, 4,4′-oxybisbenzoic acid (H₂obb), were obtained. The Eu-MOF, showing with EWDP property, is the first example of SC WLE Eu-MOFs via a dichromatic strategy on the balance of the simultaneous ligand-based and Eu(III)-based emissions at different excitation wavelengths.