Fluorinated building blocks as a source of new properties for metal–organic frameworks.

Biostimulants are becoming increasingly popular in agriculture for their ability to induce beneficial effects in crops, paving the way towards the identification of new materials with biostimulant potential. This study evaluated the potential of different concentrations of an aqueous extract (0.25%, 0.50%, and 1.00%, dry weight/water volume, respectively) obtained from duckweed (Lemna minor L.) to stimulate olive plants. Leaf net photosynthesis (Pn), leaf transpiration rate (E), stomatal conductance (gs), sub-stomatal CO₂ concentration (Ci), chlorophyll content and other plant growth parameters were investigated. As a result, the extract improved Pn, gs, Ci, chlorophyll content and plant biomass production (leaf fresh and dry weight). Furthermore, the duckweed extract generally increased the uptake of nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe) and zinc (Zn), while it did not influence the content of sodium (Na), manganese (Mn) and copper (Cu). The untargeted metabolomic profiling of the extract revealed the presence of signalling compounds (including phytohormones), phenolics and glutathione. Such broad diversity of bioactives may support the stimulatory potential observed in olive. In summary, this study revealed for the first time that duckweed could be seen as a promising species to obtain extracts with biostimulant properties in olive trees.

A new fluorinated member of the MIL-53(Al) family, displaying a unique temperature-induced phase transition, was synthesised via a solvent-free route.

In situ characterisation of the multi-step adsorption-induced breathing behaviour of F₄-MIL-53(Al) unveiled the impact of fluorination on framework flexibility and adsorption properties, offering new insights into dynamic porosity in MOFs.

Herein, we report the synthesis of Al‐TFS, a novel aluminum metal–organic framework (MOF) based on tetrafluorosuccinic acid (H₂TFS), of formula Al(OH)(TFS)·1.5H₂O, introducing a new member to the family of perfluorinated MOFs. The structure of the MOF, solved ab‐initio from laboratory powder X‐ray diffraction data, displays analogies with that of the commercially available Al‐fumarate (Basolite A520). The structure is composed of 1D infinite OH‐bridged AlO₆ octahedra chains connected by the dicarboxylic linkers, designing rhombic channels decorated by fluorine atoms. Upon water removal, the MOF undergoes a phase transition leading to a moderate expansion of the unit cell. Volumetric analysis revealed the presence of ultra‐micropores with a size lower than 4 Å. Gas sorption measurements demonstrated for Al‐TFS a slightly higher CO₂ selectivity compared to N₂ and CH₄ than the Al‐fumarate analog, with peculiar shapes of the isotherms suggesting a dynamic response of the framework to CO₂ adsorption. Using different complementary techniques (in situ infrared spectroscopy, powder X‐ray diffraction, solid‐state nuclear magnetic resonance spectroscopy, gas/vapor sorption), and density functional theory simulations, the flexibility of the new MOF was disclosed, highlighting the significant impact of fluorination in tailoring materials with structural flexibility and peculiar adsorption properties.