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1.
Chem Pharm Bull (Tokyo) ; 68(2): 167-172, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32009084

RESUMO

A heterogeneous metal catalyst enabled the intramolecular oxidative coupling of diarylamines to form carbazoles with molecular oxygen as the sole oxidant. Rh/C had efficient catalytic activity and allowed the catalyst loading to be reduced to 0.1 mol% while maintaining excellent yields of carbazoles. This reaction is operationally simple in an open-to-air setup, and provides a green and atom-economical process for an efficient synthetic approach to N-substituted carbazoles.


Assuntos
Carbazóis/síntese química , Carbazóis/química , Catálise , Técnicas de Química Sintética , Acoplamento Oxidativo , Oxigênio/química , Ródio/química
2.
Chem Commun (Camb) ; 56(21): 3119-3122, 2020 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-32090223

RESUMO

A highly efficient diastereoselective transfer hydrogenation of α-aminoalkyl α'-chloromethyl ketones catalyzed by a tethered rhodium complex was developed and successfully utilized in the synthesis of the key intermediates of HIV protease inhibitors. With the current Rh(iii) catalyst system, a series of chiral 3-amino-1-chloro-2-hydroxy-4-phenylbutanes were produced in excellent yields and diastereoselectivities (up to 99% yield, up to 99 : 1 dr). Both diastereomers of the desired products could be efficiently accessed by using the two enantiomers of the Rh(iii) catalyst.


Assuntos
Complexos de Coordenação/química , Cetonas/química , Ródio/química , Catálise , Inibidores da Protease de HIV/síntese química , Hidrogenação , Ligantes , Estrutura Molecular , Oxirredução , Estereoisomerismo , Relação Estrutura-Atividade
3.
Chem Commun (Camb) ; 56(10): 1605-1607, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31939465

RESUMO

We report the first preparation of a monoclonal antibody (mAb) that can immobilize a palladium (Pd)-complex. The allylic amination reaction using a supramolecular catalyst consisting of the Pd-complex and mAb selectively gives the (R)-enantiomer product with an enantiomeric excess (ee) of 98 ± 2%. This is in sharp contrast to the reaction catalyzed by a conventional Pd-catalyst (ee < 2%).


Assuntos
Anticorpos Monoclonais/química , Complexos de Coordenação/química , Paládio/química , Compostos Alílicos/síntese química , Compostos Alílicos/química , Aminação , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Benzilaminas/síntese química , Benzilaminas/química , Catálise , Bovinos , Complexos de Coordenação/imunologia , Complexos de Coordenação/metabolismo , Reações Cruzadas/imunologia , Feminino , Gastrópodes/química , Hemocianinas/química , Camundongos Endogâmicos BALB C , Ligação Proteica , Ródio/química , Soroalbumina Bovina/química , Estereoisomerismo , Água/química
4.
Chem Asian J ; 15(3): 360-364, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31944607

RESUMO

A RhIII -catalyzed strategy was developed for the rapid construction of highly substituted 2-pyridone scaffolds using α,ß-unsaturated oximes and fluorinated diazomalonate. The reaction proceeds through direct, site-selective alkylation based on migratory insertion and subsequent cyclocondensation. A wide substrate scope with different functional groups was explored. The requirement of fluorinated diazomalonate was explored for this transformation. The developed methodology was further extended with the synthesis of the bioactive compound.


Assuntos
Diazometano/química , Piridonas/química , Ródio/química , Catálise , Halogenação , Cinética , Piridonas/síntese química
5.
Phys Chem Chem Phys ; 21(42): 23408-23417, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31625550

RESUMO

In the field of artificial metalloenzyme (ArM) catalysis, how to identify the critical factors affecting the catalytic activity and enantioselectivity remains a challenge. In this work, the mechanism of enantioselective reduction of imine catalyzed by using [Rh(Me4Cpbiot)Cl2]·S112H Sav (denoted as S112H) and [Rh(Me4Cpbiot)Cl2]·K121H Sav (denoted as K121H) was studied by using molecular dynamics (MD) simulations combined with density functional theory (DFT) calculations. Four binding modes of imine, two proton sources (hydronium ion and lysine) and eight proposed reaction pathways were systematically discussed. The results showed that due to the anchoring effect of the mutation site of ArMs, the rhodium complex which oscillated like a pendulum was bound to a specific conformation, which further determined the chirality of the reduced product. C-Hπ, cation-π and ππ weak interactions played an important role in imine binding, and the favorable binding mode of imine was catalyzed by S112H in landscape orientation and catalyzed by K121H in portrait orientation, respectively. LYS121 is the most possible proton source in the S112H catalytic process while the proton source in the K121H catalytic process is the hydronium ion of the active sites. Furthermore, based on the reaction mechanism, modification of Rh(Me4Cpbiot)Cl2 was carried out in S112H and K121H, and the results suggested that the reaction barrier could be effectively reduced by replacing the methyl groups on Cp* with an amino group. This work gives a fundamental understanding of the mechanism of ArMs toward the imine reduction reaction, in the hope of providing a strategy for reasonable designs of ArMs with high enantioselectivity.


Assuntos
Complexos de Coordenação/química , Iminas/química , Sítios de Ligação , Catálise , Domínio Catalítico , Complexos de Coordenação/metabolismo , Teoria da Densidade Funcional , Metaloproteínas/química , Metaloproteínas/metabolismo , Simulação de Dinâmica Molecular , Oxirredução , Ródio/química , Estereoisomerismo , Termodinâmica
6.
Eur J Med Chem ; 183: 111721, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31577978

RESUMO

Thioredoxin reductase (TrxR) is often overexpressed in different types of cancer cells including hepatocellular carcinoma (HCC) cells and regarded as a target with great promise for anticancer drug research and development. Here, we have synthesized and characterized nine new designed rhodium(I) N-heterocyclic carbene (NHC) complexes. All of them were effective towards cancer cells, especially complex 1e was more active than cisplatin and manifested strong antiproliferative activity against HCC cells. In vivo anticancer studies showed that 1e significantly repressed tumor growth in an HCC nude mouse model and ameliorated liver lesions in a chronic HCC model caused by CCl4. Notably, a mechanistic study revealed that 1e can strongly inhibit TrxR system both in vitro and in vivo. Furthermore, 1e promoted intracellular ROS accumulation, damaged mitochondrial membrane potential, promoted cancer cell apoptosis and blocked the cells in the G1 phase.


Assuntos
Antineoplásicos/síntese química , Carcinoma Hepatocelular/tratamento farmacológico , Complexos de Coordenação/síntese química , Ciclo-Octanos/química , Imidazóis/química , Neoplasias Hepáticas/tratamento farmacológico , Ródio/química , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Permeabilidade da Membrana Celular , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Desenho de Fármacos , Células Hep G2 , Humanos , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos Nus , Estrutura Molecular , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade
7.
Chem Commun (Camb) ; 55(80): 12016-12019, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31498360

RESUMO

Redox-modulating anticancer drugs allow the exploitation of altered redox biology observed in many cancer cells. We discovered dinuclear RhIII(Cp*) and IrIII(Cp*) complexes that have in vitro anticancer activity superior to cisplatin and the investigational drug IT-139, while being less toxic in haemolysis and in vivo zebrafish models. The mode of action appears to be related to DNA damage and ROS-mediated stress pathways.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Dano ao DNA/efeitos dos fármacos , Irídio/química , Espécies Reativas de Oxigênio/metabolismo , Ródio/química , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/farmacologia , Complexos de Coordenação/química , Ensaios de Seleção de Medicamentos Antitumorais , Hemólise , Humanos , Ligantes , Camundongos , Oxirredução , Rutênio/química , Relação Estrutura-Atividade , Peixe-Zebra
8.
Nat Protoc ; 14(10): 2972-2985, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31541227

RESUMO

Although Csp2-Csp2 Suzuki-Miyaura couplings (SMCs) are widely used in small-molecule synthesis, related methods that allow the incorporation of Csp3-hybridized coupling partners, particularly in an asymmetric manner, are less developed. This protocol describes catalytic asymmetric SMC reactions that provide access to enantiomerically enriched cyclic allylic products. The method couples racemic allyl halide starting materials with sp2-hybridized boronic acid derivatives and is compatible with heterocyclic coupling partners. These reactions are catalyzed by a rhodium-ligand complex and typically display very high levels of enantioselectivity (>95% enantiomeric excess (ee)). In this protocol, we detail a procedure using a dihydropyridine-derived allyl chloride for the synthesis of (-)-(S)-tert-butyl-3-(4-bromophenyl)-3,6-dihydropyridine-1(2H)-carboxylate, an intermediate in the synthesis of the anticancer drug niraparib. This procedure affords 1.17 g (86% yield) of the coupling product with 96% ee. The initial experimental setup of the reaction takes 45-50 min, and the reaction is complete within 4-5 h.


Assuntos
Ácidos Borônicos/química , Técnicas de Química Sintética/métodos , Ródio/química , Compostos Alílicos/química , Catálise , Indazóis/síntese química , Piperidinas/síntese química , Estereoisomerismo
9.
J Colloid Interface Sci ; 555: 647-654, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31408763

RESUMO

Squamous cell carcinoma antigen (SCCA) has great diagnostic values for its high specificity (90-96%) in diagnosis of squamous cell carcinoma especially cancers, where electrochemical immunoassay is powerful for its accurate and reliable detection of specific tumor biomarkers at very low levels. In this work, well-defined three-dimensional dendritic core-shell rhodium@platinum-cobalt nanocrystals (Rh@PtCo NCs) were facilely prepared via a simple one-pot solvothermal strategy. Taking advantage of dramatically enhanced catalytic activity of the Rh@PtCo NCs for catechol oxidation, a label-free electrochemical immunosensor was developed for highly sensitive assay of SCCA. Under optimal conditions, the electrochemical signals were linearly correlated with the logarithm of the SCCA concentration, showing a broad linear range from 0.0001 to 10.0 ng mL-1 and a ultralow detection limit of 0.04 pg mL-1 (S/N = 3). The resultant immunosensor was further exploited for actual analysis of serum samples with convinced results. This immunosensor has good expectation in actual samples analysis and provides a universal approach for detection of other tumor markers and disease surveillance.


Assuntos
Antígenos de Neoplasias/análise , Cobalto/química , Técnicas Eletroquímicas , Imunoensaio , Nanopartículas Metálicas/química , Platina/química , Ródio/química , Serpinas/análise , Dendritos/química , Humanos , Tamanho da Partícula , Propriedades de Superfície
10.
Dalton Trans ; 48(30): 11469-11479, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31290881

RESUMO

Two rhodium complexes Rh1 and Rh2 with isoquinoline derivatives were synthesized and characterized. Both complexes displayed strong anticancer activity against various cancer cells and low cytotoxicity against non-cancer cells. These complexes triggered apoptosis via mitochondrial dysfunction that increased the levels of ROS and Ca2+ and released cytochrome C which ultimately activated caspases and the apoptosis pathway. The different biological activities of Rh1 and Rh2 could be associated with the presence of methoxy substituents on the ligands. In vivo studies showed that Rh1 effectively inhibited tumor growth in a T-24 xenograft mouse model with a less adverse effect than cisplatin. Overall, Rh1 and Rh2 induced apoptosis via mitochondrial pathways and could be developed as effective anticancer agents.


Assuntos
Antineoplásicos/química , Isoquinolinas/química , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Ródio/química , Animais , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Transporte Biológico , Cálcio/metabolismo , Caspases/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Modelos Moleculares , Conformação Molecular , Compostos Organometálicos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Inorg Chem ; 58(13): 8587-8595, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31117633

RESUMO

A new N,O-based BODIPY ligand was synthesized and further utilized to develop highly fluorescent and photostable Ru(II), Rh(III), and Ir(III) metal complexes. The complexes were fully characterized by different analytical techniques including single-crystal XRD studies. The photostabilities and live cell imaging capabilities of the complexes were investigated via confocal microscopy. The complexes localized specifically in the mitochondria of live cells and showed negligible cytotoxicities at a concentration used for imaging purposes. They also exhibited high photostabilities, with fluorescence intensities remaining above 50% after 1800 scans.


Assuntos
Compostos de Boro/metabolismo , Complexos de Coordenação/metabolismo , Corantes Fluorescentes/metabolismo , Mitocôndrias/metabolismo , Transporte Biológico , Compostos de Boro/síntese química , Compostos de Boro/efeitos da radiação , Compostos de Boro/toxicidade , Complexos de Coordenação/síntese química , Complexos de Coordenação/efeitos da radiação , Complexos de Coordenação/toxicidade , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Irídio/química , Ligantes , Microscopia Confocal , Fotodegradação , Ródio/química , Rutênio/química
12.
Molecules ; 24(10)2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-31100874

RESUMO

A convenient Rh(III)-catalyzed C-H activation and cascade [4+2] annulation for the synthesis of naphthalenone sulfoxonium ylides has been developed. This method features perfect regioselectivity, mild and redox-neutral reaction conditions, and broad substrate tolerance with good to excellent yields. Preliminary mechanistic experiments were conducted and a plausible reaction mechanism was proposed. The new type naphthalenone sulfoxonium ylides could be further transformed into multi-substituted naphthols, which demonstrates the practical utility of this methodology.


Assuntos
Dapsona/análogos & derivados , Naftóis/síntese química , Ródio/química , Catálise , Dapsona/química , Modelos Químicos , Estrutura Molecular , Naftóis/química
13.
Molecules ; 24(7)2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30970597

RESUMO

In this work, the aqueous speciation of Rh(III) in chloride medium was investigated by UV-vis spectroscopy for ligand to metal ratios R = (Cl-)/(Rh) ranging from 300 to 5000, at fixed Rh concentration (2.4 × 10-3 M). Under the chemical conditions of this work, no time evolution was observed, which allows for the fitting of the UV-vis data by Principal Component Analysis (PCA) and Multi-Curve Resolution (MCR). From this, and by comparison with literature data, the three independent species [RhCl4]-, [RhCl5]2- and [RhCl6]3- were identified, their individual absorption spectra derived and their respective contribution to the collected experimental UV-vis spectra calculated. Then, extraction of Rh(III) towards the ionic liquid trihexyltetradecylphosphonium chloride was performed. Comparison with the speciation data gives insight into the extraction mechanism and the extracted species.


Assuntos
Líquidos Iônicos/química , Compostos Organofosforados/química , Ródio/química
14.
Phys Chem Chem Phys ; 21(16): 8394-8401, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30942802

RESUMO

Two-photon photodynamic therapy (TP-PDT) plays crucial roles in curing tumors because it involves deep penetration of drugs into the tissue and has minimal damage to the surrounding cells. Our theoretical study was aimed at providing fresh insights into photosensitizers, such as [Ir(N^C)2(N^N)]+ (N^C = 2-phenylpyridine, N^N = bis-benzimidazole) and [Rh(N^C)2(N^N)]+, to treat cancer via the TP-PDT route. To better understand the properties of the complexes [Ir(N^C)2(N^N)]+ and [Rh(N^C)2(N^N)]+, the one-photon and two-photon absorption electronic spectra, energy gap (ΔES-T), strength of two-photon absorption cross-section (δ), spin-orbit matrix element (S1|HSO|Tj), and phosphorescence lifetimes (τ) were calculated by DFT and TD-DFT. The calculation results suggested that both complexes met the criteria (i.e. an efficient ISC process, enough energy to produce 1O2 and phototherapeutic window of the absorption wavelength) of photosensitizers; importantly, the designed complex [Rh(N^C)2(N^N)]+ had better performance than [Ir(N^C)2(N^N)]+, especially in the long-lived triplet excited state. It is expected that our research can make quite a few contributions to the development of photosensitizers and establish some guidelines for experiments based on TP-PDT.


Assuntos
Benzimidazóis/química , Complexos de Coordenação/química , Irídio/química , Fármacos Fotossensibilizantes/química , Piridinas/química , Ródio/química , Humanos , Modelos Moleculares , Neoplasias/tratamento farmacológico , Fotoquimioterapia , Teoria Quântica
15.
Faraday Discuss ; 215(0): 123-140, 2019 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-30993272

RESUMO

To explore the influence of a biologically inspired second and outer coordination sphere on Rh-bis(diphosphine) CO2 hydrogenation catalysts, a series of five complexes were prepared by varying the substituents on the pendant amine in the P(Et)2CH2NRCH2P(Et)2 ligands (PEtNRPEt), where R consists of methyl ester modified amino acids, including three neutral (glycine methyl ester (GlyOMe), leucine methyl ester (LeuOMe), and phenylalanine methyl ester (PheOMe)), one acidic (aspartic acid dimethyl ester (AspOMe)) and one basic (histidine methyl ester (MeHisOMe)) amino acid esters. The turnover frequencies (TOFs) for CO2 hydrogenation for each of these complexes were compared to those of the non-amino acid containing [Rh(depp)2]+ (depp) and [Rh(PEtNMePEt)2]+ (NMe) complexes. Each complex is catalytically active for CO2 hydrogenation to formate under mild conditions in THF. Catalytic activity spanned a factor of four, with the most active species being the NMe catalyst, while the slowest were the GlyOMe and the AspOMe complexes. When compared to a similar set of catalysts with phenyl-substituted phosphorous groups, a clear contribution of the outer coordination sphere is seen for this family of CO2 hydrogenation catalysts.


Assuntos
Aminoácidos/química , Dióxido de Carbono/química , Complexos de Coordenação/química , Fosfinas/química , Ródio/química , Complexos de Coordenação/síntese química , Técnicas Eletroquímicas , Hidrogenação , Conformação Molecular
16.
Chem Pharm Bull (Tokyo) ; 67(4): 393-396, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30930443

RESUMO

In order to develop an efficient organocatalyst for the enantioselective N-H insertion reaction via carbene/carbenoid, the catalytic core of the cinchona alkaloids was investigated. According to our working hypothesis of an eight-membered ring transition state in the N-H insertion reaction, two pairs of enantiomers related to 2-amino-1-phenylethanol were investigated for their chiral inducing potential. Since both (1R,2S)-isomers gave the N-phenyl-1-phenylglycine derivative enriched in the R-form, while their enantiomers gave the S-form, the 2-amino-1-phenylethanol structure is concluded to be the catalytic core of the cinchona alkaloid in the enantioselective N-H insertion reaction via rhodium(II) carbenoid.


Assuntos
Amino Álcoois/química , Alcaloides de Cinchona/química , Álcoois Benzílicos/química , Catálise , Complexos de Coordenação/química , Hidrogênio/química , Nitrogênio/química , Ródio/química , Estereoisomerismo
17.
Inorg Chem ; 58(8): 4880-4893, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30932487

RESUMO

Rhodium(III) anticancer drugs can exert preferential antimetastatic or cytotoxic activities, which are dependent on subtle structural changes. In order to delineate factors affecting the biotransformations and speciation, mer,cis-[RhCl3( S-dmso)2( O-dmso)] (A1) and mer,cis-[RhCl3( S-dmso)2(2N-indazole)] (A2) have been studied by X-ray absorption spectroscopy (XAS). Interactions of these complexes with saline buffer, cell culture media, serum proteins (albumin and apo-transferrin), native and chemically degraded collagen gels, and A549 cells have been studied using linear combination fitting (LCF) and 3D scatter plots of XAS data. Following initial aquation and hydrolysis reactions involving stepwise displacement of Cl- and S-/ O-dmso ligands, the Rh(III) complexes underwent further ligand substitution reactions with biological nucleophiles (e.g., amino acid residues of serum proteins). The reaction of A1 with chemically degraded collagen gel was postulated to be a key reason for its antimetastatic activity. Analyses of the XAS of Rh-treated bulk cells were consistent with structure-reactivity relationships in which the more reactive A1 was predominantly antimetastatic and the less reactive A2 was predominantly cytotoxic, showing relationships parallel to typical Ru(III) anticancer agents, i.e., NAMI-A ([ImH] trans-[RuCl4( S-dmso)( N-imidazole)2], ImH = imidazolium cation) and KP1019/NKP1339 (KP1019, [IndH] trans-[RuCl4(N-indazole)2], IndH = indazolium cation; NKP1339, sodium trans-[RuCl4(2N-indazole)2]), respectively.


Assuntos
Antineoplásicos/farmacologia , Dimetil Sulfóxido/química , Dimetil Sulfóxido/farmacologia , Metástase Neoplásica/prevenção & controle , Ródio/química , Ródio/farmacologia , Espectroscopia por Absorção de Raios X/métodos , Células A549 , Proteínas Sanguíneas/química , Meios de Cultura , Meios de Cultura Livres de Soro , Humanos , Relação Estrutura-Atividade
18.
Methods Mol Biol ; 1979: 285-303, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31028645

RESUMO

Mass cytometry is a variation of conventional flow cytometry using metal tagged antibodies for cell staining instead of fluorochromes and detection in a mass cytometer, a modified mass spectrometer that allows for separation of discrete masses of these metal tags by time of flight (TOF). Currently, up to 50 different metal tags are available for cell analysis. The lack of any significant mass spectral overlap and autofluorescence background makes mass cytometry uniquely suited for complex high-dimensional phenotypic and functional analysis at the single cell level, thus accelerating biomarker discovery and drug screening. Here we describe a workflow for phenotyping of human peripheral blood mononuclear cells (PBMCs) covering cell staining, instrument setup of a Fluidigm Helios™ mass cytometer, and sample acquisition, and summarize a basic workflow of data analysis.


Assuntos
Citometria de Fluxo/métodos , Imunoconjugados/imunologia , Imunofenotipagem/métodos , Leucócitos Mononucleares/imunologia , Separação Celular/métodos , Sobrevivência Celular , Humanos , Imunoconjugados/química , Irídio/química , Irídio/imunologia , Isótopos/química , Isótopos/imunologia , Leucócitos Mononucleares/citologia , Ródio/química , Ródio/imunologia , Análise de Célula Única/métodos , Coloração e Rotulagem/métodos
19.
Nanotechnology ; 30(33): 335708, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31018194

RESUMO

Zeolitic imidazole frameworks (ZIFs) are a new class of functional porous materials with attractive characters, such as gas storage, selective separation, catalysis, and drug delivery. We report herein using nanoscale ZIF-90 crystals with free aldehyde group of imidazole-2-carboxaldehyde (ICA) ligand for the selective electrochemical detection of dopamine. The averaged adsorption enthalpy ΔH (i.e., isosteric heat) of ZIF-90 to dopamine is estimated as 72 kJ mol-1 according to grand canonical Monte Carlo (GCMC) simulation. With further modification of a Pt41Rh59 alloy nanocatalyst, the electrochemical sensing performances towards dopamine are improved. The synergetic effect generated by a Pt41Rh59/ZIF-90 nanocomposite endows it a low detection limit of 1 nM and good specificity. The different anti-interference mechanisms to coexisting redox active species and amino analogues are also included in this work. The strategy demonstrated here may be extended to tune metal nodes as well as ligands of ZIFs crystals and further regulating their functionalities for different target molecules identification.


Assuntos
Dopamina/análise , Imidazóis/química , Nanocompostos/química , Bases de Schiff/química , Zeolitas/química , Ligas/química , Técnicas Eletroquímicas/métodos , Limite de Detecção , Platina/química , Ródio/química , Termodinâmica
20.
Molecules ; 24(6)2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30897722

RESUMO

During the purification of radioisotopes, decay periods or time dependent purification steps may be required to achieve a certain level of radiopurity in the final product. Actinum-225 (Ac-225), Silver-111 (Ag-111), Astatine-211 (At-211), Ruthenium-105 (Ru-105), and Rhodium-105 (Rh-105) are produced in a high energy proton irradiated thorium target. Experimentally measured cross sections, along with MCNP6-generated cross sections, were used to determine the quantities of Ac-225, Ag-111, At-211, Ru-105, Rh-105, and other co-produced radioactive impurities produced in a proton irradiated thorium target at Brookhaven Linac Isotope Producer (BLIP). Ac-225 and Ag-111 can be produced with high radiopurity by the proton irradiation of a thorium target at BLIP.


Assuntos
Actínio/química , Tório/química , Astato/química , Prótons , Radioisótopos/química , Ródio/química , Prata/química
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