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1.
Small ; : e2401226, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38511543

RESUMO

Electroredox of organics provides a promising and green approach to producing value-added chemicals. However, it remains a grand challenge to achieve high selectivity of desired products simultaneously at two electrodes, especially for non-isoelectronic transfer reactions. Here a porous heterostructure of Mo2C@Co-NC is successfully fabricated, where subnanometre ß-Mo2C clusters (<1 nm, ≈10 wt%) are confined inside porous Co, N-doped carbon using metalorganic frameworks. It is found that Co species not only promote the formation of ß-Mo2C but also can prevent it from oxidation by constructing the heterojunctions. As noted, the heterostructure achieves >96% yield and 92% Faradaic efficiency (FE) for aldehydes in anodic alcohol oxidation, as well as >99.9% yield and 96% FE for amines in cathodal nitrocompounds reduction in 1.0 M KOH. Precise control of the reaction kinetics of two half-reactions by the electronic interaction between ß-Mo2C and Co is a crucial adjective. Density functional theory (DFT) gives in-depth mechanistic insight into the high aldehyde selectivity. The work guides authors to reveal the electrooxidation nature of Mo2C at a subnanometer level. It is anticipated that the strategy will provide new insights into the design of highly effective bifunctional electrocatalysts for the coproduction of more complex fine chemicals.

2.
J Gene Med ; 24(8): e3441, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35840542

RESUMO

BACKGROUND: Synaptogyrin-2 (SYNGR2) plays an important role in regulating membrane traffic in non-neuronal cells. However, the role of SYNGR2 in esophageal squamous cell carcinoma (ESCC) remains unclear. METHODS: All original data were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and integrated via R 3.5.3. SYNGR2 expression was explored in the TCGA and GEO databases. The correlations between SYNGR2 and cancer immune characteristics were analyzed via the TIMER and TISIDB databases. RESULTS: In general, SYNGR2 was predominantly overexpressed and had reference values in the diagnosis and prognostic estimation of ESCC. Upregulated SYNGR2 was associated with poorer overall survival, disease-specific survival and T stage in ESCC. Mechanistically, we identified hub genes that included a total of 38 SYNGR2-related genes, which were tightly associated with the protein polyubiquitination pathway in ESCC patients. SYNGR2 expression was negatively related to the infiltrating levels of T helper cells. SYNGR2 methylation was positively correlated with the expression of chemokines (CCL2 and CXCL12), chemokine receptors (CCR1 and CCR2), immunoinhibitors (CXCL12 and TNFRSF4) and immunostimulators (CSF1R and PDCD1LG2) in ESCC. CONCLUSION: SYNGR2 may be used as a biomarker for determining prognosis and immune infiltration in ESCC.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Prognóstico
3.
Small ; 17(22): e2004481, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33458947

RESUMO

Composite materials with multifunctional properties usually possess synergetic effects in catalysis toward cascade reactions. In this work, a facile strategy to the encapsulation of octahedral Cu2 O nanocrystals (NCs) by metal-organic frameworks (MOFs) is reported, and an oriented growth of MOF enclosures (namely, HKUST-1) around Cu2 O NCs with desired feedstock ratio is achieved. The strategy defines the parameter range that precisely controls the etching rate of metal oxide and the MOF crystallization rate. Finally, the Cu@HKUST-1 composites with uniform morphology and controlled MOF thickness have been successfully fabricated after the reduction of Cu2 O to Cu NCs in HKUST-1. The integration of Cu NCs properties with MOF advantages helps to create a multifunctional catalyst, which exhibits cooperative catalytic activity and improved recyclability toward the one-pot cascade reactions under mild conditions involving visible-light irradiation. The superior performance can be attributed to the plasmonic photothermal effect of Cu NCs, while HKUST-1 shell provides Lewis acid sites, substrates and H2 enrichment, and stabilizes the Cu cores.

4.
J Am Chem Soc ; 139(5): 2035-2044, 2017 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-28103670

RESUMO

The selectivity control toward aldehyde in the aromatic alcohol oxidation remains a grand challenge using molecular oxygen under mild conditions. In this work, we designed and synthesized Pt/PCN-224(M) composites by integration of Pt nanocrystals and porphyrinic metal-organic frameworks (MOFs), PCN-224(M). The composites exhibit excellent catalytic performance in the photo-oxidation of aromatic alcohols by 1 atm O2 at ambient temperature, based on a synergetic photothermal effect and singlet oxygen production. Additionally, in opposition to the function of the Schottky junction, injection of hot electrons from plasmonic Pt into PCN-224(M) would lower the electron density of the Pt surface, which thus is tailorable for the optimized catalytic performance via the competition between the Schottky junction and the plasmonic effect by altering the light intensity. To the best of our knowledge, this is not only an unprecedented report on singlet oxygen-engaged selective oxidation of aromatic alcohols to aldehydes but also the first report on photothermal effect of MOFs.

5.
Foodborne Pathog Dis ; 14(8): 427-431, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28497996

RESUMO

No studies have reported the isolation of serotype Salmonella Isangi from cases of salmonellosis in mainland China. We investigated an outbreak of foodborne disease with salmonella and collected the samples from the patients and surplus foods. Salmonella strains were isolated and the serotype was identified according to the Kauffmann-White scheme. The relatedness of the isolates was determined using pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Antimicrobial susceptibility was conducted by the broth microdilution method. There were 74 diners in the case, 33 of which got ill, with an attack rate of 44.6% (33/74). A total of 24 samples were collected from the outbreak cases, six Salmonella Isangi strains were isolated and susceptible to all tested drugs. PFGE and WGS analysis suggested that the pathogen dissemination through a single or limited vector(s), the steamed fish and mixed food (fry spicy chicken, braised pork ribs, and goose leg), may be the source of infection or be cross-contaminated. We first report the characteristics of an outbreak and molecular strain relatedness of Salmonella Isangi in mainland China.


Assuntos
Surtos de Doenças , Doenças Transmitidas por Alimentos/microbiologia , Intoxicação Alimentar por Salmonella/microbiologia , Infecções por Salmonella/microbiologia , Salmonella enterica/isolamento & purificação , Adulto , Idoso , Técnicas de Tipagem Bacteriana , China/epidemiologia , Eletroforese em Gel de Campo Pulsado , Feminino , Doenças Transmitidas por Alimentos/epidemiologia , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Polimorfismo de Nucleotídeo Único , Intoxicação Alimentar por Salmonella/epidemiologia , Infecções por Salmonella/epidemiologia , Salmonella enterica/classificação , Salmonella enterica/genética , Salmonella enterica/imunologia , Sorogrupo , Adulto Jovem
6.
Small ; 11(1): 71-6, 2015 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-25201445

RESUMO

A new strategy to pre-incorporate metal precursors followed by their in situ reduction is established to prepare tiny core-shell nanoparticles (NPs) stabilized by a metal-organic framework (MOF). The obtained Pd@Co core-shell NPs of ∼2.5 nm confined in the pores of a mesoporous MOF, MIL-101, exhibit synergistic and superior catalytic performance in hydrolytic dehydrogenation of NH3 BH3 under mild conditions compared to their monometallic and alloy counterparts as well as Pd@Co NPs located on a MOF surface.

7.
Chemistry ; 20(46): 14976-80, 2014 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-25291973

RESUMO

For the first time, a ∼100% sulfonic acid functionalized metal-organic framework (MOF), MIL-101-SO3H, with giant pores has been prepared by a hydrothermal process followed by a facile postsynthetic HCl treatment strategy. The replete readily accessible Lewis acidic and especially Brønsted acidic sites distributed throughout the framework as well as high stability endow the resultant MOF exceptionally high efficiency and recyclability, which surpass all other MOF-based catalysts, for the ring opening of epoxides with alcohols (especially, methanol) as nucleophiles under ambient conditions.


Assuntos
Álcoois/química , Compostos de Epóxi/química , Ácidos de Lewis/química , Compostos Organometálicos/química , Ácidos Sulfônicos/química , Catálise , Modelos Moleculares , Porosidade
8.
ACS Appl Mater Interfaces ; 16(13): 16011-16028, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38529951

RESUMO

Superbug infections and transmission have become major challenges in the contemporary medical field. The development of novel antibacterial strategies to efficiently treat bacterial infections and conquer the problem of antimicrobial resistance (AMR) is extremely important. In this paper, a bimetallic CuCo-doped nitrogen-carbon nanozyme-functionalized hydrogel (CuCo/NC-HG) has been successfully constructed. It exhibits photoresponsive-enhanced enzymatic effects under near-infrared (NIR) irradiation (808 nm) with strong peroxidase (POD)-like and oxidase (OXD)-like activities. Upon NIR irradiation, CuCo/NC-HG possesses photodynamic activity for producing singlet oxygen(1O2), and it also has a high photothermal conversion effect, which not only facilitates the elimination of bacteria but also improves the efficiency of reactive oxygen species (ROS) production and accelerates the consumption of GSH. CuCo/NC-HG shows a lower hemolytic rate and better cytocompatibility than CuCo/NC and possesses a positive charge and macroporous skeleton for restricting negatively charged bacteria in the range of ROS destruction, strengthening the antibacterial efficiency. Comparatively, CuCo/NC and CuCo/NC-HG have stronger bactericidal ability against methicillin-resistant Staphylococcus aureus (MRSA) and ampicillin-resistant Escherichia coli (AmprE. coli) through destroying the cell membranes with a negligible occurrence of AMR. More importantly, CuCo/NC-HG plus NIR irradiation can exhibit satisfactory bactericidal performance in the absence of H2O2, avoiding the toxicity from high-concentration H2O2. In vivo evaluation has been conducted using a mouse wound infection model and histological analyses, and the results show that CuCo/NC-HG upon NIR irradiation can efficiently suppress bacterial infections and promote wound healing, without causing inflammation and tissue adhesions.


Assuntos
Infecções Bacterianas , Staphylococcus aureus Resistente à Meticilina , Animais , Hidrogéis/farmacologia , Escherichia coli , Peróxido de Hidrogênio , Espécies Reativas de Oxigênio , Fototerapia , Infecções Bacterianas/tratamento farmacológico , Antibacterianos/farmacologia , Carbono , Modelos Animais de Doenças , Nitrogênio
9.
Nat Commun ; 15(1): 3901, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38724505

RESUMO

Activation of the NF-κB pathway is strictly regulated to prevent excessive inflammatory and immune responses. In a well-known negative feedback model, IκBα-dependent NF-κB termination is a delayed response pattern in the later stage of activation, and the mechanisms mediating the rapid termination of active NF-κB remain unclear. Here, we showed IκBα-independent rapid termination of nuclear NF-κB mediated by CLK2, which negatively regulated active NF-κB by phosphorylating the RelA/p65 subunit of NF-κB at Ser180 in the nucleus to limit its transcriptional activation through degradation and nuclear export. Depletion of CLK2 increased the production of inflammatory cytokines, reduced viral replication and increased the survival of the mice. Mechanistically, CLK2 phosphorylated RelA/p65 at Ser180 in the nucleus, leading to ubiquitin‒proteasome-mediated degradation and cytoplasmic redistribution. Importantly, a CLK2 inhibitor promoted cytokine production, reduced viral replication, and accelerated murine psoriasis. This study revealed an IκBα-independent mechanism of early-stage termination of NF-κB in which phosphorylated Ser180 RelA/p65 turned off posttranslational modifications associated with transcriptional activation, ultimately resulting in the degradation and nuclear export of RelA/p65 to inhibit excessive inflammatory activation. Our findings showed that the phosphorylation of RelA/p65 at Ser180 in the nucleus inhibits early-stage NF-κB activation, thereby mediating the negative regulation of NF-κB.


Assuntos
Citoplasma , Inibidor de NF-kappaB alfa , NF-kappa B , Proteínas Tirosina Quinases , Fator de Transcrição RelA , Animais , Fosforilação , Inibidor de NF-kappaB alfa/metabolismo , Inibidor de NF-kappaB alfa/genética , Camundongos , Fator de Transcrição RelA/metabolismo , Humanos , Proteínas Tirosina Quinases/metabolismo , Proteínas Tirosina Quinases/genética , NF-kappa B/metabolismo , Citoplasma/metabolismo , Proteólise , Núcleo Celular/metabolismo , Replicação Viral , Células HEK293 , Transdução de Sinais , Camundongos Endogâmicos C57BL , Citocinas/metabolismo , Transporte Ativo do Núcleo Celular , Proteínas Serina-Treonina Quinases
10.
Zhonghua Yu Fang Yi Xue Za Zhi ; 47(5): 435-8, 2013 May.
Artigo em Zh | MEDLINE | ID: mdl-23958127

RESUMO

OBJECTIVE: To determine the contamination condition of Salmonella in broiler breeding and slaughter processing in China and to investigate the distribution of antimicrobial resistance profiles. METHODS: Five large-scale broiler holdings and fourteen slaughterhouses were chosen to detect Salmonella in Henan, Jiangsu, Sichuan and Shandong provinces in 2010. A total of 835 anal swabs and 744 chicken carcasses were sampled to compare the difference of Salmonella contamination rate.Salmonella isolates were identified by serotyping according to Kauffmann-White scheme.The antimicrobial susceptibilities of Salmonella isolates were determined by broth microdilution method and sixteen antimicrobial agents were chosen and examined. RESULTS: In total, Salmonella isolates were recovered in 56 (6.7%) specimens among 835 collected anal swabs and 122 (16.4%) specimens among 744 broiler carcasses. Positive rate of Salmonella in broiler carcasses was higher than anal swabs (χ(2) = 36.94, P < 0.05). The dominant Salmonella serovars isolated from broiler anal swabs were S.enterica serovar Indiana and S.enterica serovar Enteritidis, accounting for 58.9% (33/56) and 32.1% (18/56) respectively. The prevalent serovars in broiler carcasses were also the two serovars and occupied 29.8% (37/124), 32.2% (40/124) respectively. Nearly 95.0% (171/180) Salmonella isolates were resistant to at least one antimicrobial, 78.3% (141/180) Salmonella strains were multi-drug resistant isolates and 20 (11.1%) Salmonella isolates were resistant to 14 antimicrobials. CONCLUSION: Our findings indicated that Salmonella contamination was common and serious in commercial broiler production and processing course in China. Salmonella contamination rate in broiler slaughter processing performance was higher than broiler flocks. Additionally, antibiotic resistance of Salmonella was in serious situation.


Assuntos
Galinhas/microbiologia , Farmacorresistência Bacteriana Múltipla , Contaminação de Alimentos , Salmonella/efeitos dos fármacos , Animais , China , Indústria de Embalagem de Carne , Salmonella/classificação , Salmonella/isolamento & purificação , Sorotipagem
11.
Biomolecules ; 13(10)2023 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-37892243

RESUMO

The CRISPR-Cas system has been widely used for genome editing due to its convenience, simplicity and flexibility. Using a plasmid-carrying Cas protein and crRNA or sgRNA expression cassettes is an efficient strategy in the CRISPR-Cas genome editing system. However, the plasmid remains in the cells after genome editing. Development of general plasmid-curing strategies is necessary. Based on our previous CRISPR-Cpf1 genome-editing system in Saccharomyces cerevisiae, the crRNA, designed for the replication origin of the CRISPR-Cpf1 plasmid, and the ssDNA, as a template for homologous recombination, were introduced for plasmid curing. The efficiency of the plasmid curing was 96 ± 4%. In addition, we further simplified the plasmid curing system by transforming only one crRNA into S. cerevisiae, and the curing efficiency was about 70%. In summary, we have developed a CRISPR-mediated plasmid-curing system. The RNA-only plasmid curing system is fast and easy. This plasmid curing strategy can be applied in broad hosts by designing crRNA specific for the replication origin of the plasmid. The plasmid curing system via CRISPR-Cas editing technology can be applied to produce traceless products without foreign genes and to perform iterative processes in multiple rounds of genome editing.


Assuntos
Edição de Genes , Saccharomyces cerevisiae , Edição de Genes/métodos , Plasmídeos/genética , RNA/metabolismo , RNA Guia de Sistemas CRISPR-Cas , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
12.
Nanoscale ; 15(37): 15415-15426, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37702995

RESUMO

Selective catalysis has always been an essential process for manufacturing various fine chemicals, such as food additives, pharmaceuticals and perfumes. Practically, pure target products are difficult to obtain even after complex purification procedures during industrial production. The development of a cost-effective, highly chemoselective and long-life catalyst may be an attractive solution, but such a catalyst is elusive. Herein, a novel class of amphiphilic N-doped carbon (NC), featuring graphitic carbon (GC) and highly dispersed Cu@Co NPs, was fabricated via simple calcination of a Cu2+-doped bimetallic metal-organic framework (MOF) precusor directly. Compared with monometallic Co@GC/NC, the side reaction of CO bond hydrogenation is obviously restrained, and thus, pure target product can be systematically obtained by Cu@Co@GC/NC, highlighting the high selectivity of Cu. More importantly, an amphiphilic characteristic in Cu@Co@GC/NC is a significant knob to integrate organic substrates with water very well. This amphiphilic material shows great potential as a field-deployable pathway for dispersible metal catalysts in organic systems.

13.
Zool Stud ; 61: e20, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36330024

RESUMO

This study presents a new species of free-living marine nematode, Ptycholaimellus luoyang sp. nov., from mangrove wetlands in China. The identification was confirmed by analyzing morphological characteristics and three genes: COI, 18S rDNA, and 28S rDNA. This species is distinguished from allied species by its short cephalic setae, cylindrical pharynx with anterior swelling, sclerotized transverse ridges occurring near the dorsal tooth, rod-like gubernaculum and proximal, arch-like, slightly waved, middle curved, and distally pointed spicules. The Bayesian topology was regarded as morphological evidence of P. luoyang sp. nov. being a distinct species. Interspecific and intrageneric thresholds of the K2P distance divergence have been presented here for the first time.

14.
Zhonghua Yu Fang Yi Xue Za Zhi ; 45(12): 1065-7, 2011 Dec.
Artigo em Zh | MEDLINE | ID: mdl-22336337

RESUMO

OBJECTIVE: To know the antibiotic resistance and molecular characteristics of Listeria monocytogenes in Shandong province and to study the relationship between antibiotic resistance phenotypes and genome types. METHODS: From 2009 to 2010, a total of 80 Listeria monocytogenes isolates were collected from raw meat, cooked meat, aquatic products and other foods in 6 cities of Shandong province. The antibiotic susceptibility was measured by broth microdilution method, PFGE was performed for molecular typing and the relationship between antimicrobial resistance and PFGE patterns was analyzed. RESULTS: 16.25% (13/80) of the isolates were drug-resistant. Imipenem resistance was the most prevalent (12.50%, 10/80), followed by tetracycline and doxycycline (3.75%, 3/80 and 2.50%, 2/80). A total of the 80 isolates were subtyped into 9 antibiotic resistance patterns and 34 PFGE types which were largely dominated by the type 17 and 29. Antibiotic resistance pattern A corresponded to 79.41% (27/34) of PFGE types. CONCLUSION: The antibiotic resistance of Listeria monocytogenes in Shandong province is serious from 2009 to 2010 and there is no correlation between PFGE types and antibiotic resistance patterns.


Assuntos
Farmacorresistência Bacteriana , Microbiologia de Alimentos , Listeria monocytogenes/classificação , Listeria monocytogenes/efeitos dos fármacos , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , China , Listeria monocytogenes/isolamento & purificação , Testes de Sensibilidade Microbiana
15.
RSC Adv ; 11(56): 35326-35330, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-35493156

RESUMO

Two bifunctional CdS-MOF composites have been designed and fabricated. The hybrids exhibited synergistic photocatalytic performance toward two cascade reactions under visible light integrating photooxidation activity of CdS and Lewis acids/bases of the MOF. The composite further promoted the photodegradation of dyes benefiting from effective electron transfer between the MOF and CdS.

16.
Dalton Trans ; 49(30): 10567-10573, 2020 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-32691806

RESUMO

Evaluating the catalytic influence of metal sites on derivates obtained from the calcination of metal-organic frameworks (MOFs) is very important for the rational construction of novel MOFs. Based on this catalytic functional guidance, two new Co-MOF and CoNi-MOF crystals were designed and synthesized, and further pyrolyzed to obtain corresponding porous carbon-based catalysts. Interestingly, the derivates exhibited better catalytic performance toward the tandem reaction of dehydrogenation of NH3BH3 and subsequent hydrogenation reduction of nitro/olefin compounds than those of the CoNi-ZIF (a star MOF)-derived CoNi@carbon and most metal catalysts. Significantly, the CoNi@C maintained excellent activity, even after 30 cycles, demonstrating its great longevity and durability, which are especially important for the practical application of metal catalysts in industrial catalysis.

17.
Ann Transl Med ; 8(9): 603, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32566629

RESUMO

BACKGROUND: To investigate the epidemiological and phenotypic characteristics and molecular relatedness of L. monocytogenes, which were cultured from the blood and cerebrospinal fluid (CSF) samples isolated from two neonates. METHODS: In the present case study, two infected neonates were interviewed and epidemiological investigation performed. The phenotypic characteristics and molecular relatedness of L. monocytogenes was characterized by serotyping, pulsed-field gel electrophoresis and whole-genome sequencing (WGS). RESULTS: The field investigation found that the two neonates were born in the same hospital (Hospital B) and admitted to the neonatal department through different channels within half an hour by different nurses, where they were weighed and placed in different but adjacent incubators. Then they were cared for by the same group of nurses that evening. It is worth noting that there was no record of sanitation of the neonatal incubator of neonate-1. The serotype of the two isolated L. monocytogenes were 1/2b, with an indistinguishable pulsotypes and were sequence type (ST) 87. WGS showed that there were no core SNP differences identified. In order to explore the genomic traits associated with L. monocytogenes virulence genes, we identified the Listeria pathogenicity island 4 and found that the genome was devoid of any stress islands. There are no positive results from the environmental samples. Considering the genomic data together with epidemiological evidence and clinical symptoms, insufficient surface cleaning along with the nursing staff caring for these neonates was considered as cross-infection factors. CONCLUSIONS: To our knowledge, this is the first report of a nosocomial cross-infection of L. monocytogenes ST87 between two neonates, which carries the recently identified gene cluster expressing the cellobiose-family phosphotransferase system (PTS-LIPI-4) between two neonates. The test results of environmental samples in the hospital indicate that strict sterilization and patient isolation measures cannot be emphasized enough in neonatal nursing.

18.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 10): o2536, 2009 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-21577980

RESUMO

The title Schiff base compound, C(15)H(15)N(3)O(4), was prepared from a condensation reaction of 3-eth-oxy-4-hydroxy-benz-aldehyde and 3-nitro-phenyl-hydrazine. The mol-ecule is nearly planar; the dihedral angle between the hydroxy-benzene ring and the nitro-benzene ring is 6.57 (7)°. O-H⋯O, O-H⋯N and C-H⋯O hydrogen bonding helps to stabilize the crystal structure.

19.
Nat Commun ; 10(1): 3462, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31371708

RESUMO

Metal nanoparticles (NPs) stabilized by metal-organic frameworks (MOFs) have been intensively studied in recent decades, while investigations on the location of guest metal NPs relative to host MOF particles remain challenging and very rare. In this work, we have developed several characterization techniques, including high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) tomography, hyperpolarized 129Xe NMR spectroscopy and positron annihilation spectroscopy (PAS), which are able to determine the specific location of metal NPs relative to the MOF particle. The fine PdCu NPs confined inside MIL-101 exhibit excellent catalytic activity, absolute selectivity and satisfied recyclability in the aerobic oxidation of benzyl alcohol in pure water. As far as we know, the determination for the location of metal NPs relative to MOF particles and pore structure information of metal NPs/MOF composites by 129Xe NMR and PAS techniques has not yet been reported.

20.
ACS Appl Mater Interfaces ; 11(1): 940-947, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30556388

RESUMO

Transition-metal catalysts, particularly featuring a triple-layered core-shell structure, are very promising for practical application; however, reports on their synthesis and catalytic application for a cascade reaction were very rare. In this work, tiny Cu@Co@Ni core-shell nanoparticles (∼3.3 nm) containing Cu core, Co middle shell, and Ni outer shell stabilized by metal-organic framework (MOF) were successfully synthesized to give a quadruple-layered Cu@Co@Ni/MOF at moderate conditions. The catalyst exhibited superior catalytic performance toward the in situ hydrogenation of nitroarenes using the H2 generated from the hydrolysis of ammonia borane (NH3BH3) under mild conditions. Interestingly, the Cu@Co@Ni/MOF also showed excellent catalytic activity toward CO oxidation reaction, which outperforms those of noble-metal catalysts. To our knowledge, this is the first report on transition-metal nanoparticles with a three-layered core-shell structure stabilized by MOF as a cooperative catalyst for cascade reaction and CO oxidation.

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