Tuning of Thermometric Performances of Mixed Eu–Tb Metal–Organic Frameworks through Single‐Crystal Coordinating Solvent Exchange Reactions

Abstract

An initial investigation on the employment of targeted structural alterations, achieved through the post‐synthesis modification method, for modulation of the thermometric properties of metal–organic frameworks (MOFs) is reported. The MOF Eu0.05Tb0.95‐NBDC (NBDC = 2‐amino‐1,4‐benzenedicarboxylate) is chosen as pristine material, and its terminal N,N‐dimethylformamide (DMF) molecules are exchanged by various terminal and chelating ligands through a single‐crystal‐to‐single‐crystal coordinating solvent exchange reaction. Temperature‐dependence luminescence studies reveal that all samples are highly sensitive in the medium range with a maximum relative sensitivity of 2.6% K−1 at 190 K for Eu0.05Tb0.95‐NBDC. In addition, a shift of 50 K of the operating temperature range is evidenced for the exchanged analogs. This is attributed to the occurrence of different deactivation pathways in the exchanged analogs due to the presence of N‐donor terminal or N/O‐donor chelating aromatic ancillary ligands in the place of DMF terminal ligands in the pristine material. Overall, this work provides insights into the role of terminal and chelating ligands on the thermometric properties of mixed Eu–Tb MOFs and proposes a promising strategy to control and modulate their thermometric performances.

Fluorine extraction from organofluorine molecules to make fluorinated clusters in yttrium MOFs

“…[16][17][18][19] There is growing interest in rareearth (RE) MOFs, particularly due to their high coordination number (CN: 6-12), magnetic properties, optical properties, and therapeutic applications. [20][21][22][23][24][25] The RE metal ions tend to form dimers that oen result in MOFs with low porosity. [26][27][28] It has been widely reported that the addition of a modulator can result in RE-MOFs with larger metal clusters.…”

Fine Tuning the Hydrophobicity of a New Three-Dimensional Cu2+ MOF through Single Crystal Coordinating Ligand Exchange Transformations

“…This type of transformation, which involves the SCSC exchange of a bridging ligand that contributes to the formation of the SBU and not necessarily to the formation of the framework is quite rare in MOF chemistry. There are a series of SCSC ligand exchange/installation transformations reported including the replacement of terminal solvent molecules by various organic ligands, − or polytopic ligands by other ones, ,, or installation of bridging polytopic ligands. ,, However, to the best of our knowledge, there are only two examples involving the exchange of a monoatomic bridging ligand of the SBU of a MOF, an In 3+ MOF where a monoatomic μ–ΟΗ – bridge is exchanged by a μ–ΟMe – group and a Cu 2+ MOF where a bridging solvent molecule (μ-H 2 O) is replaced by other ones (μ-DMSO or μ-MeOH) …”

“…Single–crystal–to–single–crystal (SCSC) transformations are a subcategory of the PSM method that has attracted a significant interest because it allows the acquisition of direct structural information for the achieved modifications through single crystal X-ray crystallography. Such transformations can take place from the heterogeneous reactions of single crystals of a MOF with chemical species being in the liquid or gas phase or from their exposure to an external stimuli and can lead to the targeted modification of their structure − and the fine-tuning of their properties. ,, Several SCSC transformations have been reported in the literature which can be summarized in the following three groups: (a) insertion/removal of guest molecules, ,,,− (b) modifications of the parent structure including the coordination mode of organic ligands, or metal ion exchange (transmetalation)/insertion, ,,− and (c) changes in the coordination environment of the metal ions. − ,,,, Interestingly, such SCSC transformations have allowed not only the improvement of the magnetic, , photoluminescence, sorption, ,,,, and catalytic , properties of MOFs but also the elucidation of the exact mechanisms of these processes. Although significant progress has been realized in the investigation of a series of SCSC transformations of various types, such exchange reactions leading to the increase of the hydrophobicity of MOFs are very uncommon.…”

Lanthanide MOF-based luminescent sensor arrays for the detection of castration-resistant prostate cancer curing drugs and biomarkers

“…However, realizing crossreactivity with a single-sensor system is still highly challenging and single-system based discriminative sensors are less mature and efficient in comparison with multiple-element-based sensor arrays. 23,24 To enhance selectivity, Ln-MOF based luminescent arrays 24 have been designed, which may help estimate the patients' medication compliance.…”