Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Mais filtros

Base de dados
Intervalo de ano de publicação
Inorg Chem ; 2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-35025489


A novel binuclear ruthenium-based polyoxometalate, K6H[{Ru2Cl(H2O)(CH3COO)2}{WO(H2O)}2(PW9O34)2]·14H2O (1), was successfully synthesized by the conventional hydrothermal method. Compound 1 was well-characterized by single-crystal X-ray diffraction, X-ray powder diffraction (PXRD), infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), electrospray ionization-mass spectrometry (ESI-MS), thermogravimetric analyses (TGA), and elemental analysis. The structural unit of compound 1 contains two [A-α-PW9O34]9- building blocks at the upper and lower positions connected by two W atoms and two Ru atoms, where the W atoms and Ru atoms are arranged in a trapezoidal arrangement and the Ru atoms are bridged by acetic acid. Furthermore, compound 1 features characteristic absorption bands in the visible region, which allows the investigation of its photocatalytic properties in visible light. Under simulated sunlight radiation (λ > 400 nm), compound 1 exhibits high photocatalytic activity and good circularity toward the oxidative coupling of amines to imines at room temperature with O2 as the sole oxidant.

Dalton Trans ; 50(36): 12664-12673, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34545885


A novel ruthenium-containing polyoxometalate-based organic-inorganic hybrid, K4Na9H7.4[(AsW9O33)4(WO2)4{Ru3.2(C3H3N2)2}]·42H2O (1), was successfully synthesized by a one-step hydrothermal method under acidic conditions, which applied a self-assembly strategy between inorganic polyoxometalate based on trivacant [B-α-AsW9O33]9- {AsW9} fragments and an organic ligand, imidazole (C3H4N2). Compound 1 was further characterized by single-crystal X-ray diffraction, PXRD, IR spectroscopy, UV-Vis spectroscopy, ESI-MS, elemental analysis and TGA. Single-crystal X-ray diffraction data reveal that the polyanion consists of four trivacant Keggin-type polyanion {AsW9} building blocks bridged by four {WO6} units, leading to a crown-shaped tetrameric structure [(AsW9O33)4(WO2)4{Ru3.2(C3H3N2)2}]20.4-. The ESI-MS result reveals that the polyanion unit has excellent structural integrity in water. Moreover, the catalysis study of 1 was also further investigated, and the experimental results indicate heterogeneous catalyst 1 presents high efficiency (yield = 98%), excellent selectivity (>99%), and good recyclability for the oxidation of 1-(4-chlorophenyl)ethanol to 4'-chloroacetophenone with commercially available 70% aqueous tert-butyl hydroperoxide {TBHP (aq.)} as the oxidant at room temperature.

Nanoscale ; 13(17): 8077-8086, 2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-33899868


Five-coordinate geometry around ruthenium with highly exposed active sites has attracted intensive scientific interest due to its superior properties and extensive applications. Herein, we report a series of structurally controllable multi-Ru-bridged polyoxometalates, K5NaH10[{Ru4(H2O)n}(WO2)4(AsW9O33)4]·mH2O {1, 1-dehyd-373K, 1-dehyd-473K, 1-dehyd-573K; n = 4, m = 36; n = 4, m = 6; n = 4, m = 0; n = 0, m = 0} fabricated through a feasible assembly strategy using arsenotungstate {2, KNa12H17Cl2(As4W40O140)·29H2O} as a structure-directing unit. Systematic characterization methods identified that the six-coordinate geometry can successfully transform into five-coordinate geometry about active sites (Ru) by removing aqua ligands under high reaction temperatures. All the multi-Ru-bridged polyoxometalates demonstrated strong stability and catalytic effectiveness in the transformation of 1-(4-chlorophenyl)ethanol to 4'-chloroacetophenone under very mild conditions. 1-dehyd-573K, specifically, achieves the best catalytic effectiveness with a turnover frequency (TOF) = 25 100·h-1 owing to its unique five-coordinate geometry on the Ru sites. To our knowledge, 1-dehyd-573K outperforms other POM-based catalysts in the oxidative catalysis of 1-(4-chlorophenyl)ethanol. The heterogeneous polyoxometalates were also proven to be strongly reusable, with their structural integrities well maintained after multiple-cycle catalytic reactions.

Artigo em Chinês | MEDLINE | ID: mdl-21970120


CP23 gene of Cryptosporidium parvum was expressed in Escherichia coli, and the recombinant protein was purified. Its immunoreactivity was analyzed by Western blotting. Serum samples were collected from outpatients of different ages from August to November, 2010 in Changchun. Indirect ELISA was established to detect the anti-CP23 IgG in sera. Western blotting analysis indicated that the recombinant CP23 protein was recognized by sera from Cryptosporidium panum-infected calves and positive human sera, but not recognized by sera of mice infected with Schistosoma japonicum, sera from falciparum malaria patients and negative human sera. The overall anti-CP23 IgG positive rate was 3.2% (65/2 046). The seropositive rate was 2.7% (28/1 036) in men and 3.7% (37/1 010) in women (P > 0.05). The seropositive rates were significantly different among age groups (P < 0.05), and the age group of 71-80 had the highest positive rate (8.6%, 13/152).

Anticorpos Antiprotozoários/sangue , Criptosporidiose/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Pré-Escolar , Criptosporidiose/sangue , Cryptosporidium/isolamento & purificação , Feminino , Humanos , Imunoglobulina G/sangue , Lactente , Recém-Nascido , Masculino , Camundongos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Testes Sorológicos , Adulto Jovem
Res Rep Trop Med ; 2: 141-146, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-30881188


Background: Long-tailed and pig-tailed macaque monkeys are natural hosts of Plasmodium knowlesi, which has been identified as a fifth malaria parasite infecting humans. In this study, we investigated possible infection by this Plasmodium parasite in macaque monkeys using a combination of polymerase chain reaction amplification and sequencing. Methods: Forty-five blood samples were obtained in 2010 from macaques in northern Myanmar near Yunnan Province of China and investigated for possible infection with Plasmodium species using a nested polymerase chain reaction method for amplification of 18S SSU rRNA genes. Results: Positive amplification was obtained from one monkey, and both sequence and phylogenetic analysis indicated that the parasite was of the Hepatocystis species lineage. Conclusion: The results suggest that a combination of polymerase chain reaction amplification and sequence identification would be necessary for detection of Plasmodium knowlesi infection in both humans and its natural hosts.