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.