Functionality proportion and corresponding stability study of multivariate metal-organic frameworks

Multi-Stage Optimization of Pore Size and Shape in Pore-Space-Partitioned Metal-Organic Frameworks for Highly Selective and Sensitive Benzene Capture

Compared to exploratory development of new structure types, pushing the limits of isoreticular synthesis on a high-performance MOF platform may have higher probability of achieving targeted properties. Multi-modular MOF platforms could offer even more opportunities by expanding the scope of isoreticular chemistry. However, navigating isoreticular chemistry towards best properties on a multi-modular platform is challenging due to multiple interconnected pathways. Here on the multi-modular pacs (partitioned acs) platform, we demonstrate accessibility to a new regime of pore geometry using two independently adjustable modules (framework-forming module 1 and pore-partitioning module 2). A series of new pacs materials have been made. Benzene/cyclohexane selectivity is tuned, progressively, from 4.5 to 15.6 to 195.4 and to 482.5 by pushing the boundary of the pacs platform towards the smallest modules known so far. The exceptional stability of these materials in retaining both porosity and single crystallinity enables single-crystal diffraction studies of different crystal forms (as-synthesized, activated, guest-loaded) that help reveal the mechanistic aspects of adsorption in pacs materials.

One-Pot Synthesis of 1,3,5-Trisubstitued Pyrazoles via Immobilized Thermomyces lanuginosus Lipase (TLL) on a Metal-Organic Framework

A regioselective enzyme-catalyzed system is selected for the synthesis of 1,3,5-trisubstituted pyrazole derivatives by adding phenyl hydrazines, nitroolefins, and benzaldehydes. The reaction is performed in a one-pot vessel with a yield ranging from 49 to 90%. TLL@MMI, immobilized Thermomyces lanuginosus lipase (TLL) on a multivariate of MOF-5/IRMOF-3 (MMI), showed good performance for the catalysis of this reaction. The prepared biocatalyst was characterized by FTIR, XRD, SEM, and EDX. The thermal and solvent stability of TLL@MMI was investigated in MeOH and EtOH after 24 h incubation. In the presence of 100% concentrations of EtOH, TLL@MMI has 80% activity.

Microorganisms@aMIL-125 (Ti): An Amorphous Metal-Organic Framework Induced by Microorganisms and Their Applications

Amorphous metal-organic framework (aMOF)-based materials have attracted considerable attention as an emerging class of nanomaterials. Herein, novel microorganisms@aMIL-125 (Ti) composites including yeast@aMIL-125 (Ti), PCC 6803@aMIL-125 (Ti), and Escherichia coli@aMIL-125 (Ti) composites were respectively synthesized by self-assembling aMOFs on the microorganisms' surface. The functional groups on the microorganisms' surface induced structural defects and participated in the formation of aMIL-125 (Ti) composites. Finally, the application of microorganisms@aMIL-125 (Ti) composites for the removal of glyphosate from aqueous solution was selected as a model reaction to illustrate their potential for environmental protection. The present method is not only economical but also has other advantages including ease of operation, environmentally friendly assay, and high adsorption. The maximum adsorption capacity of aMIL-125 (Ti) was 1096.25 mg g^-1, which was 1.74 times that of crystalline MIL-125 (Ti). Therefore, the microorganisms@aMOFs composites will have broad application prospects in energy storage, drug delivery, catalysis, adsorbing toxic substances, sensing, encapsulating and delivering enzymes, and in other fields.

Rhodamine B functionalized luminescent metal-organic frameworks for ratiometric fluorescence sensing of hydroquinone

The development of sensitive and selective detection methods for hydroquinone (HQ), a phenolic organic compound with high toxicity and low degradability, is of extraordinary importance. In this work, a fluorescent sensor based on functionalized luminescent metal-organic frameworks (LMOFs) was designed and applied for the ratiometric fluorescence sensing of HQ. The sensor was prepared by the functionalization of IRMOF-3 with rhodamine B (RhB), possessing dual-emission fluorescence properties. After the addition of HQ, the blue fluorescence of the IRMOF-3 framework was gradually weakened, while the red fluorescence of RhB remained unchanged, resulting in the continuous fluorescence change of RhB@IRMOF-3 with HQ concentrations. The sensing mechanism demonstrates that HQ changes the fluorescence of the sensor via electron transfer between benzoquinone and RhB@IRMOF-3. The RhB@IRMOF-3 sensor has the advantages of a wide linear range, quick response speed, and strong specificity for HQ detection. This work is the first attempt focusing on functionalized LMOFs for HQ fluorescence detection, which has superb potential for the application to real environmental water samples.