Novel Tannic Acid-Modified Cobalt-Based Metal-Organic Framework: Synthesis, Characterization, and Antimicrobial Activity

Metal-organic frameworks (MOFs) are a class of hybrid inorganic-organic materials with typical porous structures and a unique morphology. Due to their diversity, they are extensively used in a wide range of applications such as environmental, catalysis, biomedicine, etc. In this study, a novel cobalt-based MOF modified with tannic acid (Co-TPA/TA) (TPA: terephthalic acid; TA: tannic acid) as a promising material for antimicrobial agents was synthesized and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, and thermogravimetric analysis and compared with an as-synthesized cobalt-based framework. Co-TPA/TA demonstrated good antimicrobial efficiency under optimum conditions against yeast Candida albicans ATCC 10231, Gram-negative Escherichia coli ATCC 8739, and Gram-positive Staphylococcus aureus ATCC 6538 with an inhibition zone ranging from 14 to 20 mm. Reduced ATP levels, generation of reactive oxygen species, membrane damage from cobalt ion release, and development of an alkaline microenvironment could all be contributing factors to the possible antimicrobial pathways. The novel framework can be obtained using simple, affordable, and easily accessible commercial ligands and is considered to have the potential to be used as an antimicrobial material in the future.

Two new 3D Supramolecular Frameworks as Photocatalysts for Degradation of Methyl Blue

We successfully synthesized two new supramolecular frameworks, namely {[Cu2(L1)(H2O)2]·(H2O)}n (1) and {[Ag(L2)(bpp)]2n·2(H2O)}n (2) (H2L1 = 2-hydroxy-5-sulfobenzoic acid, HL2 = 8-hydroxyquinoline-2-sulfonic acid) under hydrothermal condition. These single-crystal structures were determined via X-ray single crystal diffraction analyses. Solids 1 and 2 acted as photocatalysts and performed good photocatalytic activities for MB degradation under UV light irradiation.

A Co(II) compound: photocatalytic activity and application value in trigeminal neuralgia with minimally invasive interventional therapy guided by CT

A new thermostable Co(II)-based compound, namely [Co₃(L)₂(HTEA)₂]_n (1, HL = isonicotinic acid, H₃TEA = triethanolamine), has been successfully synthesized by the isomicotinic acid ligand and HTEA anion. The photocatalytic property of 1 was also investigated, indicating that it shows excellent photocatalytic activity for the degradation of Rhodamine B (MB) solution under the UV light irradiation. For the treatment of trigeminal neuralgia, the content of the inflammatory cytokines released into the trigeminal ganglion tissue fluid was measured with enzyme-linked immunosorbent assay (ELISA) assay. Then, the real-time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was conducted and the activation of the nuclear factor kappa-B (NF-κB) inflammatory signaling pathway was measured.

Two New 3D Supramolecular Complexes: Photocatalytic Properties and Treatment Activity for Gastric Cancer

Two new coordination polymers, [Cu₂(5-MeO-Hip)₄(py)₄]_n (1) and [Co(5-EtO-ip)(4,4'-bipy)]_n·n(MeOH) (2) (5-MeO-H₂ip is 5-methoxyisophthalic acid, 5-EtO-H₂ip is 5-ethoxyisophthalic acid, py is pyridine, and 4,4'-bipy is 4,4'-bipyridine), were created via solvothermal self-assembly. The thermal steadiness and photocatalytic functions of 1 and 2 were detected, and their application values in gastric cancer and the related mechanism were discussed. CCK-8 assay was used to determine the inhibitory activity toward gastric cancer cells' viability, and real-time RT-PCR was employed to examine the gastric cancer cells' Notch signaling pathway activity.

Two Coordination Polymers Synthesized from Various N-Donor Clusters Spaced by Terephthalic Acid for Efficient Photocatalytic Degradation of Ibuprofen in Water under Solar and Artificial Irradiation

Two coordination polymers CP1 {[Zn(II)(BIPY)(Pht)] _n } and CP2 {[Zn(HYD)(Pht)] _n } (BIPY = 4,4'-bipyridine, Pht = terephthalic acid, and HYD = 8-hydroxyquinoline) have been successfully synthesized by a hydrothermal process using zinc aqueous solution. The so-prepared compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-visible spectroscopy, thermogravimetric analysis (TGA), and cyclic voltammetry. XRD pointed to a crystalline phase for CP1, while CP2 required recrystallization, FTIR spectroscopy established the presence of characteristic bands for all the ligands, and TGA showed thermal stability up to 100 °C. The electrochemical study showed a good charge transfer between the ligands and Zn metal for both materials. The UV-vis spectra displayed a strong absorption band spreading over a wide wavelength range, encompassing UV and visible light, with a band gap of 2.69 eV for CP1 and 2.56 eV for CP2, both of which are smaller than that of ZnO. This provides an advantageous alternative to using ZnO. The 5 × 10^-5 mol L^-1 ibuprofen decomposition kinetics under solar and UV light were studied under different irradiation conditions. Good photocatalytic properties were observed due to their high surface area.

Fabrication of a polyoxotungstate/metal-organic framework/phosphorus-doped reduced graphene oxide nanohybrid modified glassy carbon electrode by electrochemical reduction and its electrochemical properties

Hybrid nanocomposites based on polyoxometalates (POMs), metal–organic frameworks (MOFs), and graphene oxide (GO) have a unique set of properties. They have specific properties such as high acidity, oxygen-rich surface, and good redox capability from POMs. In contrast, they do not have weaknesses of POMs such as a low surface area, and high solubility in aqueous media. Herein, a novel organic–inorganic nanohybrid compound based on H₃PW₁₂O₄₀ (PW₁₂), a Co-based MOF, and GO was prepared. The prepared hybrid nanocomposite (PW₁₂/MOF/GO) was characterized using different techniques. Then, a PW₁₂/MOF/GO nanocomposite modified glassy carbon electrode (GCE) was fabricated by the drop-casting method and next was dried at room temperature. Then, the PW₁₂/MOF/GO/GCE was subjected to electrochemical reduction at a constant potential of −1.5 V, in 0.1 M H₃PO₄ solution containing 0.10% w/v PW₁₂/MOF/GO additive. The morphology, electrochemical activity, and stability of the modified electrode (PW₁₂/MOF/P@ERGO/GCE) were studied with FE-SEM coupled with EDS, CV, and amperometry. The obtained results confirmed that the PW₁₂/MOF/P@ERGO/GCE could be effective in hydrogen evolution reaction (HER). The electrochemical activity of the PW₁₂/MOF/P@ERGO/GCE due to the desirable microstructure of the electrocatalyst (e.g. high active surface area and homogeneous distribution of the PW₁₂/MOF/P@ERGO), and also the synergistic effect of the blocks, is more than those of PW₁₂/GCE, MOF/GCE, PW₁₂/MOF/GCE, and P@ERGO/GCE. Moreover, the PW₁₂/MOF/P@ERGO/GCE showed an excellent long-term stability under the air atmosphere.

Fabrication of a modified glassy carbon electrode based on a polyoxotungstate/metal–organic framework/phosphorus-doped reduced graphene oxide nanohybrid.

Advances of the highly efficient and stable visible light active photocatalyst Zr(IV)-phthalate coordination polymer for the degradation of organic contaminants in water

This work presents the restoration of the Zr-phthalate coordination polymer (Zr-Ph CP) via valuable application in photocatalysis. Zr-Ph CP was facilely synthesized using a soft hydrothermal method at 70 °C, and was characterized utilizing FTIR, Raman Spectrosopy, XPS, PXRD, SEM/EDX, BET, and a hyperspectral camera. Assessment of its photocatalytic degradation potential was performed against two different dyes, the cationic methylene blue (MB) and the anionic methyl orange (MO), as frequent models of organic contaminants, under properly selected mild visible illumination (9 W) where the bandgap energy (Eg) was determined to be 2.72 eV. Effects of different initial pH values and different dyes' initial concentrations were covered. Photocatalytic degradation studies showed that Zr-Ph CP effectively degraded both dyes for initial pH 7 within about 40-60 minutes. Degradation rate constants were calculated as 0.17 and 0.13 min-1 for MB and MO, respectively. Generally, both direct and indirect mechanisms share in the degradation, where adsorption has shown an important role. The repeated use of Zr-Ph CP does not significantly affect its photocatalytic performance suggesting high water stability.

Ten polytorsional-amide-induced helical-based coordination polymers with difunctional electrochemical activities

Ten polytorsional-naphthalene-amide-based CPs constructed from different carboxylates and metal ions were obtained and exhibited difunctional electrochemical activities.

Synthesis, structure, and heterogeneous Fenton reaction of new Cu(ii)-based discrete Cu2x coordination complexes

Cu₂L₄ cage and Cu₂L₂ macrocycle were obtained and the heterogeneous Fenton reaction experiments showed that they are good photocatalysts in the photocatalytic degradation process of MB with using hydroxyl radicals and high-valence copper ions.

Six CoII coordination polymers exhibiting UV-light-driven photocatalysis for the degradation of organic dyes

Six different Co^II coordination polymers based on a new bis-pyridyl-bis-amide and polycarboxylates were obtained, showing photocatalytic activity for organic dyes.

Hydrothermal synthesis of two 2D uranyl coordination polymers: structure, luminescence, and photocatalytic degradation of rhodamine B

Two hydrothermal synthesized uranyl-organic coordination polymers showing effective photocatalytic activities for RhB degradation with quick equilibrium time in water.

A Co-MOF with a (4,4)-connected binodal two-dimensional topology: synthesis, structure and photocatalytic properties

The Co-MOF poly[[diaqua{μ₄-1,1,2,2-tetrakis[4-(1H-1,2,4-triazol-1-yl)phenyl]ethylene-κ⁴N:N':N'':N'''}cobalt(II)] benzene-1,4-dicarboxylic acid benzene-1,4-dicarboxylate], {[Co(C₃₄H₂₄N₁₂)(H₂O)₂](C₈H₄O₄)·C₈H₆O₄}_n or {[Co(ttpe)(H₂O)₂](bdc)·(1,4-H₂bdc)}_n, (I), was synthesized by the hydrothermal method using 1,1,2,2-tetrakis[4-(1H-1,2,4-triazol-1-yl)phenyl]ethylene (ttpe), benzene-1,4-dicarboxylic acid (1,4-H₂bdc) and Co(NO₃)₂·6H₂O, and characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction (PXRD), luminescence, optical band gap and valence band X-ray photoelectron spectroscopy (VB XPS). Co-MOF (I) shows a (4,4)-connected binodal two-dimensional topology with a point symbol of {4⁴·6²}{4⁴·6²}. The two-dimensional networks capture free neutral 1,4-H₂bdc molecules and bdc^2- anions, and construct a three-dimensional supramolecular architecture via hydrogen-bond interactions. MOF (I) is a good photocatalyst for the degradation of methylene blue and rhodamine B under visible-light irradiation and can be reused at least five times.

Versatile carboxylate-directed structures of ten 1D → 3D Ni(ii) coordination polymers: fluorescence behaviors and electrochemical activities

Ten 1D → 3D Ni(ii) coordination polymers based on a phenyl/methylene-mixed-bridged ligand have been obtained and structurally directed by carboxylates; they show different fluorescence behaviors and electrochemical activities.

Syntheses and photocatalytic properties of three new d10-based coordination polymers: effects of metal centres and ancillary ligands

Three d¹⁰-based coordination polymers with three different nitrogen-based ancillary ligands have been synthesized and their photocatalytic properties were explored in the decomposition of methyl violet.