One‐Step Synthesis of Hybrid Core–Shell Metal–Organic Frameworks

Epitaxial growth of MOF‐on‐MOF composite is an evolving research topic in the quest for multifunctional materials. In previously reported methods, the core–shell MOFs were synthesized via a stepwise strategy that involved growing the shell‐MOFs on top of the preformed core‐MOFs with matched lattice parameters. However, the inconvenient stepwise synthesis and the strict lattice‐matching requirement have limited the preparation of core–shell MOFs. Herein, we demonstrate that hybrid core–shell MOFs with mismatching lattices can be synthesized under the guidance of nucleation kinetic analysis. A series of MOF composites with mesoporous core and microporous shell were constructed and characterized by optical microscopy, powder X‐ray diffraction, gas sorption measurement, and scanning electron microscopy. Isoreticular expansion of microporous shells and orthogonal modification of the core was realized to produce multifunctional MOF composites, which acted as size selective catalysts for olefin epoxidation with high activity and selectivity.     

Preferential synthesis of highly conducting Tl(TCNQ) phase II nanorod networks via electrochemically driven TCNQ/Tl(TCNQ) solid-solid phase transformation

Facile synthesis and characterization of the highly conducting, thermodynamically favored, Tl(TCNQ) phase II microrods/nanorods onto conducting (glassy carbon (GC)) and semiconducting (indium tin oxide (ITO)) surfaces have been accomplished via redox-based transformation of 7,7,8,8-tetracynoquinodimethane (TCNQ) microcrystals. This electrochemically irreversible process involves the one-electron reduction of surface-confined solid TCNQ into TCNQ·^? with concomitant incorporation of the Tl⁺ _(aq) cation, from the bulk solution, at the triple-phase boundary, GC or ITO│(TCNQ_(s)/TCNQ·^? _(s))│Tl⁺ _(aq), through a nucleation/growth mechanism. Consistent with the conceptually related M(TCNQ) systems (M⁺ = Li⁺, Na⁺, K⁺, Ag⁺, and Cu⁺), the TCNQ/Tl(TCNQ) interconversion is strongly dependent upon scan rate, Tl⁺ _(aq) electrolyte concentration, and the method of attaching solid TCNQ onto the electrode surface. Spectroscopic (infrared (IR) and Raman), microscopic (scanning electron microscopy (SEM)), and surface science (X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD)) characterization of the electrochemically synthesized material revealed formation of pure Tl(TCNQ) phase II. Importantly, the generic solid-state electrochemical approach used in this study not only offers facile protocol for controllable and preferential synthesis of Tl(TCNQ) phase II but also provides access to fabricate and tune the morphology to yield microrod/nanorod networks.

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Graphical abstract Controlled synthesis of the highly conducting Tl(TCNQ) phase II with either nanowire or rod-like morphologies is achieved via a redox-based solid-solid phase interconversion of TCNQ microcrystals in the presence of a Tl⁺ _(aq) electrolyte.

     

Sub-ppt level voltammetric sensor for Hg2+ detection based on nafion stabilized l-cysteine-capped Au@Ag core-shell nanoparticles

Journal of Solid State Electrochemistry - Bimetallic nanoparticles (BMNPs) have received considerable attention due to their distinctive properties when compared to the corresponding monometallic...     

Novel Cr (III), Fe (III) and Ru (III) Vanillin Based Metallo‐Pharmaceuticals for Cancer and Inflammation Treatment: Experimental and Theoretical Studies

In this study, three novel complexes comprising trivalent Cr (III), Fe (III) and Ru (III) with imine ligand derived from 2‐amino‐3‐hydroxypyridine and o‐vanillin (H₂L) have been synthesized and characterized via wide range of spectroscopic and analytical tools such as ¹H NMR and ¹³C NMR, infrared (IR) and UV–Vis spectrophotometry, conductivity and magnetic measurements. The obtained results along with DFT data confirmed a 1:1 (metal: ligand) stoichiometry with non‐planner geometries for the three complexes. The binding action and the docking study of the prepared metal‐complexes to calf thymus DNA was also studied by absorption spectra and viscosity technique, which revealed that the three complexes interact strongly with DNA through intercalative binding mode. Significantly, these metal‐imine complexes showed strong and efficient anti‐inflammatory and antimicrobial activities against various gram‐positive (Microccus luteus), gram‐negative (Escherichia coli and Serratia marcescence) bacteria, and three strains of fungus. Moreover, all complexes exhibited more potent cytotoxicity effect on the outgrowth of different types of carcinoma cells, including human colon (HCT‐116 cell line), breast (MCF‐7 cell line), and hepatic cellular (HepG‐2), than the clinically‐proven Vinblastine standard.     

Role of Copper Oxide on Epoxy Coatings with New Intumescent Polymer-Based Fire Retardant

Epoxy resins (EP) have been used as a thermos-setting material in the field of coating, casting, bonding agent, and laminating. However, a major drawback associated with its use is the lack of good flaming properties, and it is responsible for heavy smoke along with hazardous gases considerably limiting its uses in various fields. In this study, N-ethanolamine triazine-piperizine, a melamine polymer (ETPMP), was established as a new charring-foaming agent and was successfully synthesized with ethanolamine, piperizine, cyanuric chloride, and melamine as precursor molecules via the nucleophilic substitution reaction method. Elemental analysis and Fourier transform infrared (FTIR) spectroscopy analysis were applied to approve the synthesis of ETPMP and confirmation of its structure and characterization. The epoxy coating of intumescent flame retardant (IFR) was equipped by introducing ETPMP, ammonium polyphosphate (APP), and copper oxide (CuO) in multiple composition ratios. CuO was loaded at various amounts into the IFR-coating system as a synergistic agent. The synergistic action of CuO on IFR coatings was scientifically examined by using different analytical tests such as vertical burning test (UL-94V), limited oxygen index (LOI), thermal gravimetric analysis (TGA), cone calorimeter, and scanning electron microscope (SEM). The results showed that small changes in the amount of CuO expressively amplified the LOI results and enhanced the V-0 ratings in the UL-94V test. The TGA data clearly demonstrate that the inclusion of CuO can transform the thermal deprivation behavior of coatings with a growing char slag proportion with elevated temperatures. Information from cone calorimeter data affirmed that CuO can decrease the burning factors by total heat release (THR) together with peak heat release rate (PHRR). The SEM images indicated that CuO can enrich the power and compression of the intumescent char that restricts the movement of heat and oxygen. Our results demonstrate a positive influence of CuO on the epoxy-headed intumescent flame retardant coatings.     

Hexagonal-like NiCo<Subscript>2</Subscript>O<Subscript>4</Subscript> nanostructure based high-performance supercapacitor electrodes

A novel approach of double hydroxide-mediated synthesis of nickel cobaltite (NiCo₂O₄) electro-active material by the hydrothermal method is reported. The obtained NiCo₂O₄ electro-active material displays the spinel cubic phase and hexagonal-like morphology. Thermogravimetry analysis confirms the thermal stability of the electrode material. The functional groups and phase formation of NiCo₂O₄ have been confirmed by FT-IR and Raman spectral analysis. The modified NiCo₂O₄ electrode exhibits the highest specific capacitance of 767.5 F g^?1 at a current density of 0.5 A g^?1 in 3 M KOH electrolyte and excellent cyclic stability (94 % capacitance retention after 1000 cycles at a high current density of 5 A g^?1). The excellent electrochemical performance of the electrode is attributed to the hexagonal-like morphology, which contributes to the rich surface electro-active sites and easy transport pathway for the ions during the electrochemical reaction. The attractive Faradic behavior of NiCo₂O₄ electrode has been ascribed to the redox contribution of Ni²⁺/Ni³⁺ and Co²⁺/Co³⁺ metal species in the alkaline medium. The symmetrical two-electrode cell has been fabricated using the NiCo₂O₄ electro-active material with excellent electrochemical properties for supercapacitor applications.     

Syntheses of novel 1,5-benzodiazepine derivatives: Crystal structures,spectroscopic characterizations,Hirshfeld surface analyses,molecular docking studies,DFT calculations,corrosion inhibition anticipation,and antibacterial activities

A series of newly pyrazolo-1,5-benzodiazepine derivatives ( 5 - 7 ) was performed and characterized by using ¹H, ¹³C-NMR spectroscopic measurements. The molecular and crystal structures of two compounds 2 and 7 have also been further examined by single-crystal X-ray crystallography showing that the alkyl groups are beard by sulfur atom and to pyrazolic nitrogen atom in position 2 and not in position 1 of the tricyclic compounds as described in the literature. In addition, through Hirshfeld surface analysis, molecular docking studies, and DFT calculations, the closest contact between the active atoms of the compound can be determined. Also, the Monte Carlo simulations outcomes show that compounds 2 and 7 can be considered as a good acidic corrosion inhibitor for the aluminum metal, while emphasizing that the compound 7 provides enhanced prevention. Finally, compounds 1 to 7 were evaluated for their antibacterial activity against Gram-positive and Gram-negative microbial strains such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus. The results obtained demonstrated the antibacterial activity of compounds 1 to 7 tested using the minimal inhibitory concentration.     

Bioactive Tryptophan-Based Copper Complex with Auxiliary β-Carboline Spectacle Potential on Human Breast Cancer Cells: In Vitro and In Vivo Studies

Biocompatible tryptophan-derived copper (1) and zinc (2) complexes with norharmane (β-carboline) were designed, synthesized, characterized, and evaluated for the potential anticancer activity in vitro and in vivo. The in vitro cytotoxicity of both complexes 1 and 2 were assessed against two cancerous cells: (human breast cancer) MCF7 and (liver hepatocellular cancer) HepG2 cells with a non-tumorigenic: (human embryonic kidney) HEK293 cells. The results exhibited a potentially decent selectivity of 1 against MCF7 cells with an IC₅₀ value of 7.8 ± 0.4 μM compared to 2 (less active, IC₅₀ ~ 20 μM). Furthermore, we analyzed the level of glutathione, lipid peroxidation, and visualized ROS generation to get an insight into the mechanistic pathway and witnessed oxidative stress. These in vitro results were ascertained by in vivo experiments, which also supported the free radical-mediated oxidative stress. The comet assay confirmed the oxidative stress that leads to DNA damage. The histopathology of the liver also ascertained the low toxicity of 1.