A 12-Connected [Y4((μ3-OH)4]8+ Cluster-Based Luminescent Metal-Organic Framework for Selective Turn-on Detection of F- in H2O

Fluoride ion (F^-) is one of the most hazardous elements in potable water. Over intake of F^- can give rise to dental fluorosis, kidney failure, or DNA damage. As a result, developing affordable, equipment-free and credible approaches for F^- detection is an important task. In this work, a new three dimensional rare earth cluster-based metal-organic framework assembled from lanthanide Y(III) ion, and a linear multifunctional ligand 3-nitro-4,4'-biphenyldicarboxylic acid, formulated as {[Y(μ₃-OH)]₄[Y(μ₃-OH)(μ₂-H₂O)_0.25(H₂O)_0.5]₄[μ₄-nba]₈}_n (1), where H₂nba = 3-nitro-4,4'-biphenyldicarboxylic acid, has been hydrothermally synthesized and characterized through infrared spectroscopy (IR), elemental and thermal analysis (EA), power X-ray diffraction (PXRD), and single-crystal X-ray diffraction (SCXRD) analyses. X-ray diffraction structural analysis revealed that 1 crystallizes in tetragonal system with P4¯2₁m space group, and features a 3D framework with 1D square 18.07(3)² Ų channels running along the [0,0,1] or c-axis direction. The structure of 1 is built up of unusual eight-membered rings formed by two types of {Y₄O₄} clusters connected to each other via 12 μ₄-nba^2- and 4 μ₃-OH^- ligands. Three crystallographic independent Y³⁺ ions display two coordinated configurations with a seven-coordinated distorted monocapped trigonal-prism (YO₇) and an eight-coordinated approximately bicapped trigonal-prism (YO₈). 1 is further stabilized through O-H⋯O, O-H⋯N, C-H⋯O, and π⋯π interactions. Topologically, MOF 1 can be simplified as a 12-connected 2-nodal Au₄Ho topology with a Schläfli symbol {4²⁰·6²⁸·8¹⁸}{4³}₄ or a 6-connected uninodal pcu topology with a Schläfli symbol {4¹²·6³}. The fluorescent sensing application of 1 was investigated to cations and anions in H₂O. 1 exhibits good luminescence probing turn-on recognition ability toward F^- and with a limit detection concentration of F^- down to 14.2 μM in aqueous solution (K_ec = 11403 M^-1, R² = 0.99289, σ = 0.0539). The findings here provide a feasible detection platform of LnMOFs for highly sensitive discrimination of F^- in aqueous media.

MOFSimplify, machine learning models with extracted stability data of three thousand metal-organic frameworks

We report a workflow and the output of a natural language processing (NLP)-based procedure to mine the extant metal–organic framework (MOF) literature describing structurally characterized MOFs and their solvent removal and thermal stabilities. We obtain over 2,000 solvent removal stability measures from text mining and 3,000 thermal decomposition temperatures from thermogravimetric analysis data. We assess the validity of our NLP methods and the accuracy of our extracted data by comparing to a hand-labeled subset. Machine learning (ML, i.e. artificial neural network) models trained on this data using graph- and pore-geometry-based representations enable prediction of stability on new MOFs with quantified uncertainty. Our web interface, MOFSimplify, provides users access to our curated data and enables them to harness that data for predictions on new MOFs. MOFSimplify also encourages community feedback on existing data and on ML model predictions for community-based active learning for improved MOF stability models.

Measurement(s)	thermal decomposition
Technology Type(s)	thermogravimetry

Synthesis of Europium-Doped Fluorapatite Nanorods and Their Biomedical Applications in Drug Delivery

Europium (Eu)-doped fluorapatite (FA) nanorods have a biocompatibility similar to that of hydroxyapatite (HA) for use as cell imaging biomaterials due to their luminescent property. Here, we discuss the new application of europium-doped fluorapatite (Eu-FA) nanorods as an anticancer drug carrier. The Eu-FA nanorods were prepared by using a hydrothermal method. The morphology, crystal structure, fluorescence, and composition were investigated. The specific crystal structure enables the effective loading of drug molecules. Doxorubicin (DOX), which was used as a model anticancer drug, effectively loaded onto the surface of the nanorods. The DOX release was pH-dependent and occurred more rapidly at pH 5.5 than at pH 7.4. The intracellular penetration of the DOX-loaded Eu-FA nanorods (Eu-FA/DOX) can be imaged in situ due to the self-fluorescence property. Treatment of melanoma A375 cells with Eu-FA/DOX elicited a more effective apoptosis rate than direct DOX treatment. Overall, Eu-FA exhibits potential for tracking and treating tumors and may be potentially useful as a multifunctional carrier system to effectively load and sustainably deliver drugs.