Role of zeolite encapsulated Cu(II) complexes in electron transfer as well as peroxy radical intermediates formation during oxidation of thioanisole

Catching an Oxo Vanadate Porous Acetylacetonate Covalent Adaptive Catalytic Network that Renders Mustard-Gas Simulant Harmless

In this work, we illustrated the design and development of a metal-coordinated porous organic polymer (POP) namely VO@TPA-POP via a post-synthetic metalation strategy to incorporate oxo-vanadium sites in a pristine polymer (TPA-POP) having acetylacetonate (acac) as anchoring moiety. The as-synthesized VO@TPA-POP exhibited highly robust and porous framework, which has been utilized for thioanisole (TA) oxidation to its corresponding sulfoxide. The catalyst demonstrated notable stability and recyclability by maintaining its catalytic activity over multiple reaction cycles without any significant loss in activity. The X-ray absorption spectroscopy (XAS) and density functional theory (DFT) analysis establish the existence of V(+4) oxidation state along with the VO(O)4 active sites into the porous network and the most energetically feasible mechanistic pathway involved in the TA oxidation, respectively, indicating the role of electron density associated with vanadium center during the catalytic transformation. Thus, this work aims at the demonstration of versatility and potential of VO@TPA-POP as a porous heterogeneous catalyst for the TA oxidation followed by decontamination of sulfur mustards (HD's) to their corresponding less toxic sulfoxides in a more efficient and greener way.

Photocatalytic Evaluation of the Ternary Composite CdSO4-ZnAl LDH/ZnS in Hydrogen Production without a Sacrificial Reagent

In this work, a layered double hydroxide support modified with cadmium was synthesized by a one-pot coprecipitation method. Then, it was sulfured in different percentages by a solvothermal method. Next, the samples were analyzed using various characterization techniques like XRD, DRS, FTIR, N2 physisorption, PL spectroscopy, TEM, and SEM. Finally, the synthesized and uncalcined materials were assessed in hydrogen production from water and a methanol-water solution under UV-light irradiation. The results showed that the sulphuration improves the photocatalytic activity, reaching a maximum rate constant of hydrogen production of 7403 µmol/g∙h in a methanol-water solution and 1326 µmol/g∙h in water.

Removal of Tetracycline Hydrochloride by Photocatalysis Using Electrospun PAN Nanofibrous Membranes Coated with g-C3N4/Ti3C2/Ag3PO4

In order to improve the photocatalytic performance of g-C3N4, the g-C3N4/Ti3C2/Ag3PO4 S-type heterojunction catalyst was prepared by electrostatic assembly method, and then the g-C3N4/Ti3C2/Ag3PO4/PAN composite nanofiber membrane was prepared by electrospinning technology. The morphology and chemical properties of the nanofiber membrane were characterized by SEM, FTIR, and XRD, and the photocatalytic degradation of tetracycline hydrochloride (TC) in water by the nanofiber membrane was investigated. The results showed that g-C3N4/Ti3C2/Ag3PO4 could be successfully loaded on PAN and uniformly distributed on the surface of composite nanofiber membrane by electrospinning technology. Increasing the amount of loading and catalyst, lowering the pH value and TC concentration of the system were conducive to the oxidation and degradation of TC. The nano-fiber catalytic membrane had been recycled five times and found to have excellent photocatalytic stability and reusability. The study of catalytic mechanism showed that h+, •OH and •O2− were produced and participated in the oxidation degradation reaction of TC, and •O2− plays a major role in catalysis. Therefore, this work provides a new insight into the construction of high-performance and high-stability photocatalytic system by electrospinning technology.

Continuous Flow Photochemical Synthesis of 3-Methyl-4-arylmethylene Isoxazole-5(4H)-ones through Organic Photoredox Catalysis and Investigation of Their Larvicidal Activity

Isoxazole-5(4H)-ones are heteropentacycle compounds found in several bioactive molecules with pharmaceutical and agrochemical properties. A well-known multicomponent reaction between β-ketoester, hydroxylamine, and aromatic aldehydes leads to 3-methyl-4-arylmethylene isoxazole-5(4H)-ones, in mild conditions. The initial purpose of this work was to investigate whether the reaction might be induced by light, as described in previous works. Remarkable results were obtained using a high-power lamp, reducing reaction times compared to methodologies that used heating or catalysis. Since there are many examples of successful continuous flow heterocycle synthesis, including photochemical reactions, the study evolved to run the reaction in flow conditions and scale up the synthesis of isoxazolones using a photochemical reactor set-up. Eight different compounds were obtained, and among them, three showed larvicidal activity on immature forms of Aedes aegypti in tests that investigated its growth inhibitory character. Mechanistic investigations indicate that the reactions occur through organic photoredox catalysis.

Cancer-Targeted Chitosan-Biotin-Conjugated Mesoporous Silica Nanoparticles as Carriers of Zinc Complexes to Achieve Enhanced Chemotherapy In Vitro and In Vivo

Despite being the most common component of numerous metalloenzymes in the human body, zinc complexes are still under-rated as chemotherapeutic agents. Herein, the present study opens up a key route toward enhanced chemotherapy with the help of two Zn^II complexes (ZnMBC) synthesized alongside Mannich base ligands to upsurge biological potency. Further, well-established mesoporous silica nanoparticles (MSNs) have been chosen as carriers of the titled metallodrugs in order to achieve anticancer drug delivery. A pH-sensitive additive, namely, chitosan (CTS) conjugated with biotin is tagged to MSNs for the targeted release of core agents inside tumors selectively. In general, CTS blocks ZnMBC inside the mesopores of MSNs, and biotin acts as a targeting ligand to improve tumor-specific cellular uptake. CTS-biotin surface decoration significantly enhanced the cellular uptake of ZnMBC through endocytosis. A panel of four human cancer cell lines has revealed that ZnMBC (1/2)@MSNs-CTS-biotin nanoparticles (NPs) exhibits unprecedented enhanced cytotoxicity toward cancer cells with IC₅₀ values ranging from 6.5 to 28.8 μM through induction of apoptosis. NPs also possess great selectivity between normal and cancer cells despite this potency. Two-photon-excited in vitro imaging of normal (HEK) and cancer (HeLa) cells has been performed to confirm the biased drug delivery. Also, NP-induced apoptosis was found to be dependent on targeting DNA and ROS generation. Moreover, a lower range of LD₅₀ values (153.6-335.5 μM) were observed upon treatment zebrafish embryos with NPs in vivo. Because of the anatomical similarity to the human heart, the heart rate of NP-treated zebrafish has been analyzed in assessing the cardiac functions, which is in favor of the early clinical trials of ZnMBC (1/2)@MSNs-CTS-biotin candidates for their further evaluation as a chemotherapeutic and chemopreventive agent toward human cancers, especially adenocarcinoma.

Unveiling the urease like intrinsic catalytic activities of two dinuclear nickel complexes towards the in situ syntheses of aminocyanopyridines

Designing metal complexes as functional models for metalloenzymes remains one of the main targets in synthetic bioinorganic chemistry. Furthermore, the utilization of the product(s) derived from the catalytic reaction for subsequent organic transformation that occurs in biological systems is an even more difficult challenge for biochemists. Urease, the most efficient enzyme known, catalyzes the hydrolysis of urea and it contains an essential dinuclear Ni^II cluster in the active site. Inspired by the catalytic properties of urease, two dinickel(ii) complexes viz. Ni₂L¹₂(OAc)₂(H₂O) (1) and Ni₂L²₂(OAc)₂(H₂O) (2) [HL1 = 2,4-dimethyl-6-{[(2'-dimethyl aminoethyl)methylamino]methyl}-phenol and HL2 = 2,4-dichloro-6-{[(2'-dimethyl aminoethyl)methylamino]methyl}-phenol] have been synthesized and characterized in this report. Both the complexes have shown the urease kind of activity with the liberation of ammonia from urea in aqueous solution. The plausible mechanistic pathway and kinetics of the reactions have been studied. Besides, the liberated ammonia has been utilized in the one-pot synthesis of biologically active products like 2-amino-3-cyanopyridines and their derivatives in aqueous medium with excellent yields.

Studies on the influence of the nuclearity of zinc(ii) hemi-salen complexes on some pivotal biological applications

Experimental and theoretical corroboration of the various biological applications of two nuclearity-dependent dimeric and trimeric Zn(ii) hemi-salen complexes.