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1.
DNA Cell Biol ; 43(5): 245-257, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38489601

RESUMEN

Clear cell renal cell carcinoma (ccRCC) is a malignant tumor of kidney epithelial cells, one of the most common tumors in the world. Transforming growth factor beta (TGFß)1 is a crucial factor that induces epithelial-mesenchymal transition (EMT) in cancer cells. microRNA-141-3p (miR-141-3p) is a microRNA that is considered a tumor suppressor. However, the role and mechanism of miR-141-3p in TGFß1-induced ccRCC cells are not fully understood. This study investigated the roles of miR-141-3p and its target gene in regulating EMT in ccRCC development. 786-0 and Caki-1cells were treated with TGFß1 to induce EMT. The levels of miR-141-3p and TGFß2 were determined by quantitative real-time polymerase chain reaction and Western blotting. The progression of EMT was evaluated by E-cadherin detection by immunofluorescence, and E-cadherin, N-cadherin, and vimentin detection by Western blotting. Furthermore, migration and invasion capacities were assessed using a Transwell system. The direct binding of miR-141-3p with the target gene TGFß2 was confirmed by dual luciferase reporter gene assay. Results indicated that TGFß1 treatment decreased the protein abundance of E-cadherin while increasing the protein expression of N-cadherin and vimentin, indicating TGFß1-induced EMT was constructed successfully. Moreover, TGFß1 treatment repressed the expression of miR-141-3p. miR-141-3p mimics reversed the effect of TGFß1 on the migration, invasion, and expression of E-cadherin, N-cadherin, and vimentin. The miR-141-3p directly binds with the 3' untranslated region of TGFß2 mRNA and suppresses its expression. Furthermore, TGFß2 overexpression abrogated the above changes regulated by miR-141-3p mimics. Taken together, miR-141-3p inhibited TGFß1-induced EMT by suppressing the migration and invasion of ccRCC cells via directly targeting TGFß2 gene expression.


Asunto(s)
Carcinoma de Células Renales , Movimiento Celular , Transición Epitelial-Mesenquimal , Regulación Neoplásica de la Expresión Génica , Neoplasias Renales , MicroARNs , Factor de Crecimiento Transformador beta2 , MicroARNs/genética , MicroARNs/metabolismo , Humanos , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/metabolismo , Carcinoma de Células Renales/patología , Transición Epitelial-Mesenquimal/genética , Transición Epitelial-Mesenquimal/efectos de los fármacos , Neoplasias Renales/genética , Neoplasias Renales/metabolismo , Neoplasias Renales/patología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Factor de Crecimiento Transformador beta2/genética , Factor de Crecimiento Transformador beta2/metabolismo , Factor de Crecimiento Transformador beta2/farmacología , Línea Celular Tumoral , Movimiento Celular/genética , Movimiento Celular/efectos de los fármacos , Factor de Crecimiento Transformador beta1/farmacología , Factor de Crecimiento Transformador beta1/metabolismo , Factor de Crecimiento Transformador beta1/genética , Progresión de la Enfermedad
2.
Int J Nanomedicine ; 19: 1571-1595, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38406600

RESUMEN

Long-acting injectable microspheres have been on the market for more than three decades, but if calculated on the brand name, only 12 products have been approved by the FDA due to numerous challenges in achieving a fully controllable drug release pattern. Recently, more and more researches on the critical factors that determine the release kinetics of microspheres shifted from evaluating the typical physicochemical properties to exploring the microstructure. The microstructure of microspheres mainly includes the spatial distribution and the dispersed state of drug, PLGA and pores, which has been considered as one of the most important characteristics of microspheres, especially when comparative characterization of the microstructure (Q3) has been recommended by the FDA for the bioequivalence assessment. This review extracted the main variables affecting the microstructure formation from microsphere formulation compositions and preparation processes and highlighted the latest advances in microstructure characterization techniques. The further understanding of the microsphere microstructure has significant reference value for the development of long-acting injectable microspheres, particularly for the development of the generic microspheres.


Asunto(s)
Ácido Láctico , Ácido Poliglicólico , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ácido Poliglicólico/química , Ácido Láctico/química , Liberación de Fármacos , Microesferas , Preparaciones de Acción Retardada , Tamaño de la Partícula
3.
J Oncol ; 2022: 3382360, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36245973

RESUMEN

Bladder cancer is a malignant tumor that occurs on the mucous membrane of the bladder. It is the most common malignant tumor of the urinary system and one of the top ten common tumors in the whole body. This bibliometric analysis was applied to identify the characteristics of global scientific output, the hotspots, and frontiers about treatment on bladder cancer with Chinese medicine monomer over the past 22 years. We retrieved publications published from 2000 to 2021 and their recorded information from Web of Science Core Collection (WoSCC). VOSviewer and CiteSpace were used to analyze bibliometric indicators and visualize the trend and hotspots of researches on bladder cancer with Chinese medicine monomer. Altogether, 658 original articles were reviewed, and the results showed that the annual number of publications (Np) shows an upward trend over the past 22 years as a whole. The US produced the most papers, and the number of citations (Nc) and H-index of the US ranked first. Johns Hopkins University and BJU International were the most prolific affiliation and journal, respectively. Recently, the keywords "NF-kappa B" appeared frequently. Besides, quercetin is the most thorough research in the treatment of bladder cancer with Chinese herbal compound, but whether quercetin is the most potent compound needs further study.

4.
Angew Chem Int Ed Engl ; 61(46): e202204008, 2022 11 14.
Artículo en Inglés | MEDLINE | ID: mdl-36066469

RESUMEN

Formaldehyde (HCHO) is a crucial C1 building block for daily-life commodities in a wide range of industrial processes. Industrial production of HCHO today is based on energy- and cost-intensive gas-phase catalytic oxidation of methanol, which calls for exploring other and more sustainable ways of carrying out this process. Utilization of carbon dioxide (CO2 ) as precursor presents a promising strategy to simultaneously mitigate the carbon footprint and alleviate environmental issues. This Minireview summarizes recent progress in CO2 -to-HCHO conversion using hydrogenation, hydroboration/hydrosilylation as well as photochemical, electrochemical, photoelectrochemical, and enzymatic approaches. The active species, reaction intermediates, and mechanistic pathways are discussed to deepen the understanding of HCHO selectivity issues. Finally, shortcomings and prospects of the various strategies for sustainable reduction of CO2 to HCHO are discussed.


Asunto(s)
Dióxido de Carbono , Formaldehído , Catálisis , Metanol/metabolismo , Oxidación-Reducción
5.
Small ; 18(14): e2107750, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35224845

RESUMEN

It is still a great challenge to explore hydrogen evolution reaction (HER) electrocatalysts with both lower overpotential and higher stability in acidic electrolytes. In this work, an efficient HER catalyst, Ru@COF-1, is prepared by complexation of triazine-cored sp2 carbon-conjugated covalent organic frameworks (COFs) with ruthenium ion. Ru@COF-1 possesses high crystallinity and porosity, which are beneficial for electrocatalysis. The large specific surface area and regular porous channels of Ru@COF-1 facilitate full contact between reactants and catalytic sites. The nitrogen atoms of triazines are protonated in the acidic media, which greatly improve the conductivity of Ru@COF-1. This synergistic effect makes the overpotential of Ru@COF-1 about 200 mV at 10 mA cm-2 , which is lower than other reported COFs-based electrocatalysts. Moreover, Ru@COF-1 exhibits exceptionally electrocatalytic durability in the acidic electrolytes. It is particularly stable and remains highly active after 1000 cyclic voltammetry cycles. Density functional theory calculations demonstrate that tetracoordinated Ru-N2 Cl2 moieties are the major contributors to the outstanding HER performance. This work provides a new idea for developing protonated HER electrocatalysts in acidic media.

6.
Sci Total Environ ; 805: 150288, 2022 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-34536868

RESUMEN

Recovery of the nitrogen (N) and phosphorus (P) in wastewater would help to minimize eutrophication and their reuse would lead to a more sustainable society. Sewage sludge and fly ash were used to fabricate ceramsite in the laboratory. After modified with alkali or lanthanum it was shown in benchtop experiments to effectively recover N and P from real wastewater treatment plant effluent. The N&P-adsorbed ceramsite was then applied as an eco-friendly, slow-release fertilizer to promote the germination, growth and blooming of Impatiens commelinoides, realizing the recycling of N and P from wastewater. Emergy analysis shows that such recycling is more sustainable than the current two approaches (i.e., landfill and incineration) for sludge disposal. This work thus demonstrates a sustainable solution combining the reuse of solid waste, effective wastewater purification and recovery of N and P nutrients. Applying the technologies demonstrated would help to minimize the environmental impact of wastewater and solid waste.


Asunto(s)
Fósforo , Aguas Residuales , Adsorción , Mezclas Complejas , Nitrógeno , Aguas del Alcantarillado , Eliminación de Residuos Líquidos
7.
Angew Chem Int Ed Engl ; 60(42): 22826-22832, 2021 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-34396665

RESUMEN

A nitrogen-stabilized single-atom catalyst containing low-valence zinc atoms (Znδ+ -NC) is reported. It contains saturated four-coordinate (Zn-N4 ) and unsaturated three-coordinate (Zn-N3 ) sites. The latter makes Zn a low-valence state, as deduced from X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, electron paramagnetic resonance, and density functional theory. Znδ+ -NC catalyzes electrochemical reduction of CO2 to CO with near-unity selectivity in water at an overpotential as low as 310 mV. A current density up to 1 A cm-2 can be achieved together with high CO selectivity of >95 % using Znδ+ -NC in a flow cell. Calculations suggest that the unsaturated Zn-N3 could dramatically reduce the energy barrier by stabilizing the COOH* intermediate owing to the electron-rich environment of Zn. This work sheds light on the relationship among coordination number, valence state, and catalytic performance and achieves high current densities relevant for industrial applications.

8.
J Endourol ; 35(12): 1801-1807, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34235972

RESUMEN

Purpose: To evaluate the impact of reresection on the clinical outcome in patients with primary high-risk nonmuscle-invasive bladder cancer (NMIBC) who initially received en bloc transurethral resection. Methods: A retrospective analysis of data on eligible high-risk NMIBC with en bloc resection from June 2015 to June 2019 was performed. Patients were divided into two groups based on the presence or absence of reresection after the initial en bloc resection. In the first group (reresection group), patients underwent en bloc reresection within 6 weeks. In the second group (non-reresection group), patients did not undergo en bloc reresection. Pathologic findings in patients with reresection and cystoscopic findings in all patients 3 months after initial resection were recorded. The primary study endpoint was recurrence-free survival (RFS). The secondary outcomes were the residual rate of the tumor after initial en bloc resection, tumor upstaging rate, and progression-free survival. Results: We identified 115 eligible patients, including 51 (44.3%) who underwent reresection within 6 weeks of the initial en bloc resection and 64 (55.7%) who did not undergo en bloc reresection after the initial en bloc resection. The clinicopathologic features were similar in patients with or without reresection. On finding tumor residues after the first en bloc resection, there were three cases (5.9%) in the reresection group compared with two cases (3.1%) in the non-reresection group (p = 0.473). Two patients (3.9%) in the reresection group had tumor progression to muscle-invasive bladder cancer, whereas one patient (1.6%) in the non-reresection group exhibited tumor progression (p = 0.430). The 1-year RFS rate was 94.1% in the reresection group and 90.6% in the non-reresection group (p = 0.269). In multivariate analysis, multifocality and T1 staging were independent prognostic factors for recurrence in patients with high-risk NMIBC who underwent en bloc resection. Conclusion: In patients with high-risk NMIBC not exceeding 4 cm in diameter with no more than four lesions and not in the anterior bladder wall, reresection after en bloc resection seems to have failed to improve the patient's prognosis. We predict that the future trend in the treatment of patients with high-risk NMIBC is from reresection to en bloc resection. However, a randomized controlled clinical study is required to confirm this hypothesis.


Asunto(s)
Neoplasias de la Vejiga Urinaria , Cistectomía , Estudios de Seguimiento , Humanos , Invasividad Neoplásica , Estudios Retrospectivos , Vejiga Urinaria , Neoplasias de la Vejiga Urinaria/cirugía
9.
Front Oncol ; 11: 663119, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34290980

RESUMEN

BACKGROUND: Small cell neuroendocrine carcinoma (SCNEC) of the ureter is a rare tumour, accounting for less than 0.5% of all ureteral tumours. SCNEC tumours are highly aggressive and patients have a poor prognosis. Ureteral SCNEC colliding with other pathological types of tumours is extremely rare. In this paper, we present the case of a patient with ureteral small cell carcinoma colliding with squamous cell carcinoma and review the literature regarding the clinicopathological features, treatment and prognosis of thus tumour. To the best of our knowledge, this is the second identified case of ureteral SCNEC colliding with SCC. CASE PRESENTATION: A 64-year-old male patient presented with a history of 1 month of gross haematuria and 3 months of left flank pain. CT urography revealed a soft tissue mass in the upper ureter, which was slightly enhanced on contrast-enhanced CT. Nephroureterectomy was performed after the patient was diagnosed with a tumour in the left ureter. Microscopy and immunohistochemical examination confirmed the mass to be a SCNEC collision with SCC. Two months after the surgery, the patient received adjuvant chemotherapy (cisplatin/etoposide). After 14 months of follow-up, no local recurrence or distant metastasis was found. CONCLUSION: Ureteral collision carcinoma with SCNEC predominantly occurs in Asian individuals, is difficult to diagnose preoperatively and is highly invasive. The current management of ureteral collision carcinoma is a comprehensive treatment based on surgery.

10.
Chemosphere ; 276: 130266, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34088107

RESUMEN

Heterostructured catalysts play a significant role in the photodegradation of pollutants in wastewater. Combining the large surface of nanobelts with the high photocatalytic property of titanium dioxide (TiO2) nanoparticles is a promising method for preparing photocatalysts, which have an advanced photocatalytic activity and are easy to precipitate. In this work, titanium dioxide nanobelts (NB) and acid corroded titanium dioxide nanobelts (C-NB) were synthesized via a hydrothermal process under alkaline conditions. Their surfaces were then loaded with palladium oxide (PdO) nanoparticles to prepare heterostructured photocatalysts (PdO-NB and PdO-C-NB) by a well-designed chemical precipitation method. The photodegradation efficiencies of the four catalysts for phenol, as well as for methyl orange, were tested and the order of degradation efficiency was found to be PdO-C-NB > PdO-NB > C-NB > NB. A degradation efficiency of 61% for phenol was achieved within 90 min using PdO-C-NB, which was nearly twice as much as using NB. The enhanced photocatalytic property of PdO-C-NB was due to the large specific surface area, abundant photocatalytic active sites and the low recombination rate of electron-hole pairs. Therefore, the degradation of phenol and methyl orange was speeded up considerably. Considering the high catalytic activity of PdO-C-NB, the heterostructure catalyst is of great significance to the degradation of organic wastewater, and has an important impact on our ecological environment and human health.


Asunto(s)
Paladio , Fenol , Humanos , Fenoles , Fotólisis
11.
J Hazard Mater ; 419: 126458, 2021 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-34186422

RESUMEN

Electrochemical dechlorination is a prospective strategy to remediate trichloroethylene (TCE)-contaminated groundwater. In this work, iron-nitrogen-doped carbon (FeNC) mimicking microbiological dechlorination coenzymes was developed for TCE removal under environmentally related conditions. The biomimetic FeNC-900, FeNC-1000, and FeNC-1100 materials were synthesized via pyrolysis at different temperatures (900, 1000, and 1100 °C). Due to the synergistic effect of Fe-N4 active sites and graphitic N sites, FeNC-1000 had the highest electron transfer efficiency and the largest electrochemical active surface area among the as-synthesized FeNC catalysts. The pseudo-first-order rate constants for TCE reduction using FeNC-1000 catalyst are 0.19, 0.28 and 0.36 h-1 at potentials of -0.8 V, -1.0 V and -1.2 V, respectively. Active hydrogen and direct electrons transfer both contribute to the dechlorination from TCE to C2H4 and C2H6. FeNC maintain a high reactivity after five reuse cycles. Our study provides a novel approach for the dechlorination of chlorinated organic contaminants in groundwater.


Asunto(s)
Agua Subterránea , Tricloroetileno , Biomimética , Carbono , Hierro , Nitrógeno , Estudios Prospectivos
12.
Aging (Albany NY) ; 13(2): 3045-3059, 2021 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-33460398

RESUMEN

Nondegradable transvaginal polypropylene meshes for treating pelvic organ prolapse (POP) are now generally unavailable or banned due to serious adverse events. New tissue engineering approaches combine degradable scaffolds with mesenchymal stem/stromal cells from human endometrium (eMSC). In this study, we investigate effect of microRNA-138 (miR-138) regulation on bone marrow-derived mesenchymal stem cells (BMSCs) and the efficacy of BMSC transplantation therapy in a rat POP model. We first identified FBLN5 as a target of miR-138. miR-138, fibulin-5 (FBLN5), interleukin-1ß (IL-1ß), and elastin expression in uterosacral ligament of POP patients and controls were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. After isolation and identification, BMSCs were treated to alter their expression of miR-138 or FBLN5. Proliferation of BMSCs was analyzed by CCK-8. After establishing the rat pelvic floor dysfunction (PFD) model, we evaluated efficacy of BMSC injection by applying leak point pressure (LPP) and the conscious cystometry (CMG) tests. miR-138 inhibition resulted in increased viability of BMSCs and elevated their secretion of elastin, while downregulating IL-1ß expression. BMSCs with inhibited miR-138 improved LPP and conscious CMG results in vivo. Taken together, miR-138 could be a potential therapeutic target for treating POP in conjunction with tissue engineering.


Asunto(s)
Elastina/metabolismo , Proteínas de la Matriz Extracelular/metabolismo , Interleucina-1beta/metabolismo , Trasplante de Células Madre Mesenquimatosas/métodos , MicroARNs/metabolismo , Prolapso de Órgano Pélvico/terapia , Proteínas Recombinantes/metabolismo , Anciano , Animales , Células de la Médula Ósea/metabolismo , Diferenciación Celular/fisiología , Femenino , Silenciador del Gen , Humanos , Células Madre Mesenquimatosas/metabolismo , MicroARNs/genética , Persona de Mediana Edad , Prolapso de Órgano Pélvico/genética , Prolapso de Órgano Pélvico/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal/fisiología
13.
ChemSusChem ; 13(23): 6360-6369, 2020 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-32672415

RESUMEN

A straightforward procedure has been developed to prepare a porous carbon material decorated with iron by direct pyrolysis of a mixture of a porous polymer and iron chloride. Characterization of the material with X-ray diffraction, X-ray absorption spectroscopy, and electron microscopy indicates the presence of iron carbide nanoparticles encapsulated inside the carbon matrix, and elemental mapping and cyanide poisoning experiments demonstrate the presence of atomic Fe centers, albeit in trace amounts, which are active sites for electrochemical CO2 reduction. The encapsulated iron carbide nanoparticles are found to boost the catalytic activity of atomic Fe sites in the outer carbon layers, rendering the material highly active and selective for CO2 reduction, although these atomic Fe sites are only present in trace amounts. The target material exhibits near-unity selectivity (98 %) for CO2 -to-CO conversion at a small overpotential (410 mV) in water. Furthermore, the material holds potential for practical application, as a current density over 30 mA cm-2 and a selectivity of 93 % can be achieved in a flow cell.

14.
J Hazard Mater ; 389: 122137, 2020 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-32004841

RESUMEN

Developing efficient catalysts for persulfate (PS) activation is important for the potential application of sulfate-radical-based advanced oxidation process. Herein, we demonstrate single iron atoms confined in MoS2 nanosheets with dual catalytic sites and synergistic catalysis as highly reactive and stable catalysts for efficient catalytic oxidation of recalcitrant organic pollutants via activation of PS. The dual reaction sites and the interaction between Fe and Mo greatly enhance the catalytic performance for PS activation. The radical scavenger experiments and electron paramagnetic resonance results confirm and SO4- rather than HO is responsible for aniline degradation. The high catalytic performance of Fe0.36Mo0.64S2 was interpreted by density functional theory (DFT) calculations via strong metal-support interactions and the low formal oxidation state of Fe in FexMo1-xS2. FexMo1-xS2/PS system can effectively remove various persistent organic pollutants and works well in a real water environment. Also, FexMo1-xS2 can efficiently activate peroxymonosulfate, sulfite and H2O2, suggesting its potential practical applications under various circumstances.

15.
Nature ; 575(7784): 598-599, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31776485
16.
Int J Surg Case Rep ; 53: 479-482, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30567074

RESUMEN

INTRODUCTION: Hemangiomas are benign tumor formations of capillaries and blood vessels which are commonly found in various organs. However they are extremely rare in urinary bladder accounting for only 0.6% of all urinary bladder tumors. The differentiating of these benign tumors from malignant neoplasms are important since they have extremely different prognostic features as well as therapeutic strategies. Here we reported a female patient diagnosed with bladder cavernous hemangioma (BCH) after recent pelvic radiotherapy for the cervical cancer and reviewed relevant literatures. CASE PRESENTATION: We reported a case of 49 years old female patient with persistent painless hematuria for 12 days. Computed tomography revealed a small lesion on the superior wall of the urinary bladder with acute clot retention. Cystoscopy confirmed a solid papillary pedunculated mass with a measuring of 1.0 × 0.5 cm located on the superior posterior wall and surrounded by distended vessels. Transurethral resection of the mass was then performed and the pathological report indicated a cavernous hemangioma of the urinary bladder. In a one and half year follow-up, no tumor recurrence or bleeding was found. CONCLUSIONS: The cavernous hemangioma in urinary bladder is rare and cystoscopic is a gold standard for diagnosis. Treatment options are vary for individuals and pathologic findings are vital for differentiating it from malignant potential tumors. A history of cancer related radiation therapy seems to be a risk factor for BCH.

17.
Chemistry ; 24(50): 13205-13212, 2018 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-29878461

RESUMEN

Organic micro- and nanostructures are expected to be promising candidates for micro- and nanophotonic materials with desirable properties owing to their low cost, flexible molecular design, and tunable self-assembly. Among these candidates, well-known squaraine dyes (SQs) have rarely been investigated because of their nonfluorescent properties in the solid state and because their optical behavior varies with changes in morphology. In this contribution, two novel 1,2-SQs, SQM and SQB, with strong bright-yellow to red fluorescence emission in the crystalline state, were designed and structured at the molecular level and by solvent adjustment. Their self-assembly behavior was studied, and it was revealed that the SQM assembly provided 1D microrods, whereas 1D microrods (Z-SQB⋅CH2 Cl2 ) and 2D microplates (E-SQB⋅2 CH3 OH) could be obtained from SQB assemblies through a solution-based self-assembly method. The varied assembly behaviors of these SQs were attributed to different π-π stacking interactions that resulted in different molecular conformations and packing modes. These assemblies exhibited distinct optical properties, and in particular, SQB⋅solvent assemblies showed multiple thermo- and vapochromic effects. Thus, the SQB assemblies are potential fluorescent sensors for organic solvent vapors. More importantly, favorable optical-waveguide properties were observed in these SQ-based microstructures.

18.
RSC Adv ; 8(25): 13921-13932, 2018 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-35539320

RESUMEN

A general approach to prepare composite films of metal-organic frameworks and graphene has been developed. Films of copper(ii)-based HKUST-1 and HKUST-1/graphene composites were grown solvothermally on glassy carbon electrodes. The films were chemically tethered to the substrate by diazonium electrografting resulting in a large electrode coverage and good stability in solution for electrochemical studies. HKUST-1 has poor electrical conductivity, but we demonstrate that the addition of graphene to HKUST-1 partially restores the electrochemical activity of the electrodes. The enhanced activity, however, does not result in copper(ii) to copper(i) reduction in HKUST-1 at negative potentials. The materials were characterised in-depth: microscopy and grazing incidence X-ray diffraction demonstrate uniform films of crystalline HKUST-1, and Raman spectroscopy reveals that graphene is homogeneously distributed in the films. Gas sorption studies show that both HKUST-1 and HKUST-1/graphene have a large CO2/N2 selectivity, but the composite has a lower surface area and CO2 adsorption capacity in comparison with HKUST-1, while CO2 binds stronger to the composite at low pressures. Electron paramagnetic resonance spectroscopy reveals that both monomeric and dimeric copper units are present in the materials, and that the two materials behave differently upon hydration, i.e. HKUST-1/graphene reacts slower by interaction with water. The changed gas/vapour sorption properties and the improved electrochemical activity are two independent consequences of combining graphene with HKUST-1.

19.
Nat Commun ; 8(1): 489, 2017 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-28887452

RESUMEN

Significant efforts have been devoted over the last few years to develop efficient molecular electrocatalysts for the electrochemical reduction of carbon dioxide to carbon monoxide, the latter being an industrially important feedstock for the synthesis of bulk and fine chemicals. Whereas these efforts primarily focus on this formal oxygen abstraction step, there are no reports on the exploitation of the chemistry for scalable applications in carbonylation reactions. Here we describe the design and application of an inexpensive and user-friendly electrochemical set-up combined with the two-chamber technology for performing Pd-catalysed carbonylation reactions including amino- and alkoxycarbonylations, as well as carbonylative Sonogashira and Suzuki couplings with near stoichiometric carbon monoxide. The combined two-reaction process allows for milligram to gram synthesis of pharmaceutically relevant compounds. Moreover, this technology can be adapted to the use of atmospheric carbon dioxide.Electroreduction of CO2 to CO is a potential valorisation pathway of carbon dioxide for fine chemicals production. Here, the authors show a user-friendly device that couples CO2 electroreduction with carbonylation chemistry for up to gram scale synthesis of pharmaceuticals even under atmospheric CO2.

20.
Angew Chem Int Ed Engl ; 56(23): 6468-6472, 2017 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-28466962

RESUMEN

In a comparative study of the electrocatalytic CO2 reduction, cobalt meso-tetraphenylporphyrin (CoTPP) is used as a model molecular catalyst under both homogeneous and heterogeneous conditions. In the former case, employing N,N-dimethylformamide as solvent, CoTPP performs poorly as an electrocatalyst giving low product selectivity in a slow reaction at a high overpotential. However, upon straightforward immobilization of CoTPP onto carbon nanotubes, a remarkable enhancement of the electrocatalytic abilities is seen with CO2 becoming selectively reduced to CO (>90 %) at a low overpotential in aqueous medium. This effect is ascribed to the particular environment created by the aqueous medium at the catalytic site of the immobilized catalyst that facilitates the adsorption and further reaction of CO2 . This work highlights the significance of assessing an immobilized molecular catalyst from more than homogeneous measurements alone.

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