Fabrication of a Robust Lanthanide Metal–Organic Framework as a Multifunctional Material for Fe(III) Detection, CO₂ Capture, and Utilization

By employing a tricarboxylate ligand 1-(4-carboxybenzyl)-1<i>H</i>-pyrazole-3,5-dicarboxylic acid (H₃L), four lanthanide metal–organic frameworks (Ln-MOFs) formulated as {[LnL­(H₂O)₂]­·H₂O}_<i>n</i> (Ln = Eu, <b>1</b>; Gd, <b>2</b>; Tb, <b>3</b>; Dy, <b>4</b>) have been prepared under hydrothermal conditions. Single-crystal X-ray analyses reveal that compounds <b>1</b>–<b>4</b> are isomorphous and exhibit a three-dimensional network structure featuring a one-dimensional rectangular channel with a size of ca. 7.8 Å × 12.1 Å along the <i>b</i> axis. The framework shows strong stabilities toward high temperature, humid air, water, as well as acid/base environments. Efficient ligand-sensitized characteristic luminescence can be observed in the visible region for Eu- and Tb-based compounds. Detailed property investigation shows that <b>TbL</b> is a promising multifunctional material, which can quantitatively detect Fe­(III) ions in the solution mixtures of Fe­(II)/Fe­(III), selectively adsorb CO₂ over CH₄, and be applied as catalysts in cyclization reaction with epoxides and CO₂

Cation-Induced Strategy toward an Hourglass-Shaped Cu₆I₇^– Cluster and Its Color-Tunable Luminescence

We have designed and synthesized a series of two-dimensional materials featuring with a (3,6)-connected <b>kgd</b> layer, in which an unprecedented anionic Cu₆I₇^– cluster was first trapped through a cation-induced synthetic strategy. The emission colors of these cluster-based luminophores gradually shift from blue to yellow as the monovalent cations (Li⁺, Na⁺, NH₄⁺, K⁺, TEA⁺) located between the neighboring layers changed. SCXRD analyses discover that the variation of the emission may be attributed to the transformation of the hourglass-shaped Cu₆I₇^– cluster. The bright, tunable, and broad luminescent emissions make them promising candidates as phosphors for light-emitting diodes (LEDs). Particularly, compound <b>1-TEA</b> emitting intensive yellow light with high luminescence quantum efficiency (QY = 79.9%) shows extremely high thermal, pH, organic solvent, and mechanical photostabilities. By employing it as a yellow phosphor, we fabricate a series of white lighting materials with high color rendering index (CRI)