The aromatic C(spsup.2)-H functionalization of unprotected naphthols with α-phenyl-α-diazoesters under mild conditions catalyzed by CuCl and CuClsub.2 exhibits high efficiency and unique ...ortho-selectivity. In this study, the combination of density functional theory (DFT) calculations and experiments is employed to investigate the mechanism of C-H functionalization, which reveals the fundamental origin of the site-selectivity. It explains that CuCl-catalyzed ortho-selective C-H functionlization is due to the bimetallic carbene, which differs from the reaction catalyzed by CuClsub.2 via monometallic carbene. The results demonstrate the function of favourable H-bond interactions on the site- and chemo-selectivity of reaction through stabilizing the rate-determining transition states in proton (1,3)-migration.
The copper catalyzed reaction of N-monosubstituted hydrazones with carbon tetrabromide leads to formation of expected dibromodiazadienes and unexpected dibromostyrenes. The experimental and ...theoretical study of the reaction revealed a key role of N-centered radicals, which can eliminate aryl radicals to form the corresponding dibromostyrenes. Alternatively, the oxidation of intermediate N-centered radicals by Cu(II) results in the corresponding diazadienes. These two reaction pathways are competitive directions of the reaction. Consequently, the reaction can be useful for the synthesis of both dibromostyrenes and rare dibromodiazadienes.
Pyranoquinolinones synthesized from citral were used for Cu-catalyzed N-arylation with a wide range of arylboric acids. The reaction proceeded well with a broad substrate scope, providing a direct ...way to access highly functional pyranoquinolinone core structure derivatives in yields of up to 80%. Compared to citral, the compounds we obtained have a much better inhibitory effect on HeLa cervical cancer cells, and compound 3p has an ICsub.50 value of 4.6 μM, lower than cisplatin’s 5.9 μM.
The Ce-Cu-SAPO-18 samples were prepared by the ion exchange method. Physicochemical properties of the samples were systematically characterized by a number of analytical techniques, and Ce doping and ...hydrothermal temperature effects on NH.sub.3-SCR activity of Cu-SAPO-18 were also investigated. The results show that doping of Ce increased NH.sub.3-SCR activity and hydrothermal stability of the Cu-SAPO-18 sample. After Ce doping, a more amount of the isolated Cu.sup.2+ ions entered the D6R and the catalyst structure was more stable. The structure and catalytic activity of Ce-Cu-SAPO-18 remained almost intact after hydrothermal aging at 650 °C. After hydrothermal aging at 850 °C, however, the structure of Ce-Cu-SAPO-18 was greatly destroyed, and its catalytic activity declined remarkably. The high-temperature hydrothermal aging treatment led to decreases in amount of the isolated Cu.sup.2+ ions and acidic sites, destroying in the zeolitic structure, and drop in NH.sub.3-SCR activity.
The eco-friendly synthesis of metal oxides pn junction composite with high visible light absorption and its photoelectrochemical monitoring on antibiotics is reported. The In
O
-CuO pn heterojunction ...composite was successfully prepared by in-situ hydrothermal decoration of CuO on the prepared In
O
using a simple reflux method. The obtained nanorods like In
O
-CuO pn heterojunction exhibited high conductivity with excellent stability for the facilitated photoelectrochemical detection of ornidazole (ONZ) that plays a role in aquatic toxicology. The photo-stability and optical characteristics of the In
O
-CuO heterojunction composite were analyzed through photocurrent and UV-visible studies. Mechanism of ONZ signaling has been proposed with appropriate band levels derived by Mott-Schottky analysis. An optimized In
O
-CuO heterojunction detects ONZ in the range 0.05-65.3 nM with 0.0092 nM as the limit of detection at - 0.45 V (vs. Ag/AgCl) working potential. The practical applicability of the sensor device was tested in chicken meat, human urine, and lake water samples containing ONZ. The recoveries of real samples were above 95% and results obtained were compared with electrochemical methods.
Copper homeostasis is strictly regulated by protein transporters and chaperones, to allow its correct distribution and avoid uncontrolled redox reactions. Several studies address copper as involved ...in cancer development and spreading (epithelial to mesenchymal transition, angiogenesis). However, being endogenous and displaying a tremendous potential to generate free radicals, copper is a perfect candidate, once opportunely complexed, to be used as a drug in cancer therapy with low adverse effects. Copper ions can be modulated by the organic counterpart, after complexed to their metalcore, either in redox potential or geometry and consequently reactivity. During the last four decades, many copper complexes were studied regarding their reactivity toward cancer cells, and many of them could be a drug choice for phase II and III in cancer therapy. Also, there is promising evidence of using 64Cu in nanoparticles as radiopharmaceuticals for both positron emission tomography (PET) imaging and treatment of hypoxic tumors. However, few compounds have gone beyond testing in animal models, and none of them got the status of a drug for cancer chemotherapy. The main challenge is their solubility in physiological buffers and their different and non-predictable mechanism of action. Moreover, it is difficult to rationalize a structure-based activity for drug design and delivery. In this review, we describe the role of copper in cancer, the effects of copper-complexes on tumor cell death mechanisms, and point to the new copper complexes applicable as drugs, suggesting that they may represent at least one component of a multi-action combination in cancer therapy.
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•Copper participates in cell proliferation, apoptosis, and ferroptosis induction.•Copper transporters proteins are involved in platinum antitumor compound resistance.•Copper ions induce oxidative stress and complexes used as an antitumor drug.•Copper can be useful as a radiotherapy agent in co-therapies in cancer.
► Detailed histological observations comparing the effects of Cu-NPs with CuSO4 in rainbow trout. ► Cu-NPs caused similar types of pathologies to CuSO4. ► There were material-type effects with Cu-NPs ...sometimes producing more injury. ► The first detailed observations on the trout brain injury for copper. ► Pathologies can occur indirectly without having elevated Cu in the internal organs.
It is unclear whether copper nanoparticles are more toxic than traditional forms of dissolved copper. This study aimed to describe the pathologies in gill, gut, liver, kidney, brain and muscle of juvenile rainbow trout, Oncorhynchus mykiss, exposed in triplicate to either a control (no added Cu), 20 or 100μgl−1 of either dissolved Cu (as CuSO4) or Cu-NPs (mean primary particle size of 87±27nm) in a semi-static waterborne exposure regime. Fish were sampled at days 0, 4, and 10 for histology. All treatments caused organ injuries, and the kinds of pathologies observed with Cu-NPs were broadly of the same type as CuSO4 including: hyperplasia, aneurisms, and necrosis in the secondary lamellae of the gills; swelling of goblet cells, necrosis in the mucosa layer and vacuole formation in the gut; hepatitis-like injury and cells with pyknotic nuclei in the liver; damage to the epithelium of some renal tubules and increased Bowman's space in the kidney. In the brain, some mild changes were observed in the nerve cell bodies in the telencephalon, alteration in the thickness of the mesencephalon layers, and enlargement of blood vessel on the ventral surface of the cerebellum. Changes in the proportional area of muscle fibres were observed in skeletal muscle. Overall the data showed that pathology from CuSO4 and Cu-NPs were of similar types, but there were some material-type effects in the severity or incidence of injuries with Cu-NPs causing more injury in the intestine, liver and brain than the equivalent concentration of CuSO4 by the end of the experiment, but in the gill and muscle CuSO4 caused more pathology.
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