Recent advances in process engineering and upcoming applications of metal-organic frameworks.

Progress in metal-organic frameworks (MOFs) has advanced from fundamental chemistry to engineering processes and applications, resulting in new industrial opportunities. The unique features of MOFs, such as their permanent porosity, high surface area, and structural flexibility, continue to draw industrial interest outside the traditional MOF field, both to solve existing challenges and to create new businesses. In this context, diverse research has been directed toward commercializing MOFs, but such studies have been performed according to a variety of individual goals. Therefore, there have been limited opportunities to share the challenges, goals, and findings with most of the MOF field. In this review, we examine the issues and demands for MOF commercialization and investigate recent advances in MOF process engineering and applications. Specifically, we discuss the criteria for MOF commercialization from the views of stability, producibility, regulations, and production cost. This review covers progress in the mass production and formation of MOFs along with future applications that are not currently well known but have high potential for new areas of MOF commercialization.

Breathing-Assisted Selective Adsorption of C8 Alkyl Aromatics in Zn-Based Metal-Organic Frameworks.

Invited for the cover of this issue are Purna Chandra Rao, Minyoung Yoon and co-workers at Kyungpook National University, Gachon University, POSTECH, Korea Atomic Energy Research Institute and the University of Sydney. The image depicts how single C8 isomers are selectively isolated from a mixture. Read the full text of the article at 10.1002/chem.202102640.

Transformation of One-Dimensional Achiral Structure to Three-Dimensional Chiral Structure: Mechanistic Study and Catalytic Activities of Chiral Structure.

We have isolated two copper-based coordination polymers through solvent diffusion and solvothermal methods using copper salt, furan dicarboxylic acid (FDC), 4,4'-bipyridine (bpy) in MeOH/ethylene glycol, and water solvents. Compound 1 is adopting P21/c space group and adopts a one-dimensional wirelike structure with a free carboxylate anion. Compound 2 crystallizes in chiral space group P65. This is a three-dimensional structure with helical chains. This helicity might be the reason for chiral generation and symmetry breaking. We have converted compound 1 to compound 2 using grinding, followed by a solvothermal method. The circular dichroism data of 2 showed that it is an enantioenriched compound. We have shown that compound 2 is a very good catalyst for chemo- and regioselective enamination reaction and for azide-alkyne Huisgen cycloaddition, respectively.

Correction: Organic guest molecule induced ultrafast breathing of an epitaxially grown metal-organic framework on a self-assembled monolayer.

Correction for 'Organic guest molecule induced ultrafast breathing of an epitaxially grown metal-organic framework on a self-assembled monolayer' by Purna Chandra Rao et al., Chem. Commun., 2021, DOI: 10.1039/d1cc03721h.

Organic guest molecule induced ultrafast breathing of an epitaxially grown metal-organic framework on a self-assembled monolayer.

We report epitaxially grown new two-dimensional metal-organic framework (MOF) thin films on a self-assembled monolayer (SAM). We fabricated these epitaxial thin-films using stepwise layer-by-layer seeding followed by solvothermal treatment. The MOF thin films exhibit ultrafast structural flexibility (through breathing) compared to their bulk samples upon uptake of organic guest molecules.

Potential Utilization of Metal-Organic Frameworks in Heterogeneous Catalysis: A Case Study of Hydrogen-Bond Donating and Single-Site Catalysis.

Crystalline solid materials are platforms for the development of effective catalysts and have shown vast benefits at the frontiers between homogeneous and heterogeneous catalysts. Typically, these crystalline solid catalysts outperformed their homogeneous analogs due to their high stability, selectivity, better catalytic activity, reusability and recyclability in catalysis applications. This point of view, comprising significant features of a new class of porous crystalline materials termed as metal-organic frameworks (MOFs) engendered the attractive pathway to synthesize functionalized heterogeneous MOF catalysts. The present review includes the recent research progress in developing both hydrogen-bond donating (HBD) MOF catalysts and MOF-supported single-site catalysts (MSSCs). The first part deals with the novel designs of urea-, thiourea- and squaramide-containing MOF catalysts and study of their crucial role in HBD catalysis. In the second part, we discuss the important classification of MSSCs with existing examples and their use in desired catalytic reactions. In addition, we describe the relative catalytic efficiency of these MSSCs with their homogeneous and similarly reported analogs. The precise knowledge of discussed heterogeneous MOF catalysts in this review may open the door for new research advances in the field of MOF catalysis.

Magnetic diversity in three-dimensional two-fold-interpenetrated structures: a story of two compounds.

A magnetostructural correlation has been carried out for two newly synthesized two-fold-interpenetrated three-dimensional structures. Compound 1, denoted as [Ni(L1)(L2)]·2DMF (where L1 is 1,4-benzene-dicarboxylic acid (BDC), L2 is 4,4-oxybis-(N-(pyridine-4-yl)benzamide), and DMF is N,N'-dimethylformamide), was observed to have a three-dimensional structure with two-fold interpenetration. Compound 2, denoted as [Co(L3)(L2)]·2DMF (where L3 is 2,5-thiopehene-dicarboxylic acid (TDC)), was also observed to display a three-dimensional structure with an architecture identical to that of compound 1. Both compounds were well characterised using several techniques including single-crystal X-ray diffraction, powder X-ray diffraction, TGA, and IR. Magnetism and specific heat measurements of compound 1 revealed a canted-antiferromagnetic transition at TN ≈ 4 K and a field-induced spin-flop transition at a relatively low field strength. These exotic features were attributed to the low-symmetry space group P(1[combining macron]) and single-ion anisotropy of the Ni2+ sub-lattice. In contrast, compound 2 was found to be weakly antiferromagnetic in nature with a negligible interaction between the magnetic Co2+ ions.

The effect of cluster size on the optical band gap energy of Zn-based metal-organic frameworks.

We have synthesized three Metal-Organic Frameworks (MOFs) in which Zn metal ions form the secondary building unit, and 4,4'-sulfonyldibenzoic acid (SDB) serves as the ligand: [[Zn(DMF)(SDB)](DMF), 1, [Zn(3)(DMF)(3)(SDB)(3)](DMF), 2 and [Zn(3)(OH)(2)(SDB)(2)] (DMF)(2), 3, where DMF = dimethyl formamide]. Compound contains a paddle-wheel type Zn dimer, compound contains a Zn trimer motif, and contains a one-dimensional Zn-OH-Zn chain. These building units may be considered to be Zn clusters. We have measured and theoretically calculated the band gap energy and by theoretical investigations we found that the cluster size plays an important role in the band gap energy, however additional effects are observed. The larger cluster size corresponds to a larger band gap energy, however the cavity of the trimer based compound (2) traps a solvent molecule that decreases the band gap energy.

Chemiluminescence and Toluidine Blue as Diagnostic Tools for Detecting Early Stages of Oral Cancer: An invivo Study.

BACKGROUND: There is a need for development and use of diagnostic aids that help the dental specialist more readily identify and assess Potentially Malignant Epithelial Lesions (PMELs) and Oral Squamous Cell Carcinoma (OSCC). This study was done to assess the value of two such commercially available tools: chemiluminescent light kit or ViziLite and 1% toluidine blue. AIMS AND OBJECTIVES: a) To detect epithelial dysplastic changes using chemiluminescene (commercially available as ViziLite) and toluidine blue staining in PMELs and OSCC patients and compare the results obtained with histopathological examination. b) To determine whether these techniques can be used to detect early epithelial dysplastic changes in clinically normal appearing oral mucosa of high risk (with habits) patients. MATERIALS AND METHODS: A total of 60 patients- 25 patients with PMELs, specifically oral leukoplakia, 10 patients with clinically diagnosed OSCC and 25 high risk patients with no clinically visible lesion, were screened with ViziLite and toluidine blue staining; followed by incisional biopsy. RESULTS: Sensitivity and specificity of ViziLite were calculated to be 95.45% and 84.6% respectively. ViziLite detected early epithelial dysplastic changes in one high risk patient with clinically normal appearing oral mucosa. Sensitivity and specificity of toluidine blue were calculated to be 86.36% and 76.9% respectively. CONCLUSION: ViziLite was relatively reliable in screening PMELs compared to toluidine blue, and was a useful chair side diagnostic aid.