Lanthanide Discrimination with Hydroxyl-Decorated Flexible Metal–Organic Frameworks

Abstract

We report two new highly crystalline metal−organic frameworks (MOFs), derived from the natural amino acids serine (1) and threonine (2), featuring hexagonal channels densely decorated with hydroxyl groups belonging to the amino acid residues. Both 1 and 2 are capable of discriminating, via solid-phase extraction, a mixture of selected chloride salts of lanthanides on the basis of their size, chemical affinity, and/or the flexibility of the network. In addition, this discrimination follows a completely different trend for 1 and 2 because of the different locations of the hydroxyl groups in each compound, which is evocative of steric complementarity between the substrate and receptor. Last but not least, the crystal structures of selected adsorbates could be resolved, offering unprecedented snapshots on the capture process and enabling structural correlations with the separation mechanism.

Rare earth elements: Mendeleev’s bane, modern marvels

“…Because of the small size of the Ti 4+ cation (0.61 Å, CN 6), the smaller HREs were more likely to fill the lacunar host matrix. The ability of MOFs to preferentially adsorb REs has also been examined (30). The separation factors were limited, but notably, the selectivity for HREs was reversed to that for LREs when the organic linker was modified.…”

Synthesis and Enhanced Capture Properties of a New BioMOF@SWCNT‐BP: Recovery of the Endangered Rare‐Earth Elements from Aqueous Systems

“…In this context, with the aim to make a step forward on MOF‐based technologies for element recovery and water remediation, we present a novel, flexible, and self‐standing MOF‐based single‐walled carbon nanotube buckypaper [ 33,36 ] (BioMOF@SWCNT‐BPs) as a new and highly performant material in REEs recovery ( Figure ). The highly crystalline bioMOF, previously reported by us [ 17 ] and prepared from the natural amino acid L‐threonine, has been homogeneously dispersed within a thin (150 µm) membrane, made with an entangled CNT network and produced by multiple steps of dispersion and filtration for lanthanide recovery from water. Among the different MOF subfamilies, bioMOFs, [ 37,38 ] constructed using biomolecule derivatives as building blocks and often affording water stable materials, emerge as valuable systems to study the capture properties and application in water remediation, either for their chemical functionalization or for being eco‐friendly porous materials.…”

“…In this context, metal–organic frameworks (MOFs), [ 11–13 ] which are porous materials known for a great potential in separation, are demonstrating their high potentiality even in lanthanide separation. [ 14–17 ] Water‐stable MOFs offer tunable microporosity and the possibility to tailor their channels with the appropriate functionalities to improve affinity for target elements, even in a selective manner. [ 18–20 ] Several works related to MOFs and MOF‐based materials have been reported for the recovery of lanthanides.…”

“…[ 18–20 ] Several works related to MOFs and MOF‐based materials have been reported for the recovery of lanthanides. [ 16,17 ] However, they exhibit important disadvantages such as difficult handling or leaks of fillers, that compromise any industrial process.…”

Synthesis, structure and magnetic properties of an oxamate-based 1D coordination polymer built on pentametallic links

“…Oxamate ligands are attractive synthetic tools with a rich coordination chemistry that facilitates the design and preparation of molecular materials. [1][2][3][4][5][6][7] While phenyl-based oxamate ligands, [8][9][10][11] and amino-acid-based oxamate ligands now represent the bulk of the investigations, [12][13][14][15][16][17][18][19][20][21][22][23] a sub-class of aromatic oxamate ligands that are substituted with additional -non-oxamic-coordinating groups starts to gain attention. [24][25][26][27][28][29][30][31][32][33] Like the amino-acid-based oxamate ligands, such multi-polydentate ligands bearing additional carboxylato, hydroxido or N-donor groups offer diverse coordination modes with metal ions, which give access to new structural types.…”