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排序方式: 共有129条查询结果,搜索用时 304 毫秒
101.
Veerasamy Ravichandran Samuggam Sumitha Cheah Yi Ning Ooi Yi Xian Ung Kiew Yu Neeraj Paliwal 《Green Chemistry Letters and Reviews》2020,13(2):102-116
ABSTRACT The synthesized ZnO NPs using durian rind in solution has shown maximum absorption at 355.5?nm with the bandgap of 3.33?eV, spectrophotometrically. SEM and TEM studies revealed that the shape of the synthesized ZnO NPs was spherical with an average size of 280 and 283?nm, respectively. However, DLS analysis of ZnO NPs revealed the average particle size of 456?d.nm. The presence of [100], [002], [101], [102], [110], [103], [200], [112] and [201] planes in XRD corroborate the formation of pure wurtzite structure of ZnO NPs. Synthesized ZnO NPs showed remarkable photocatalytic activity on degradation of methylene blue and sulfanilamide, antioxidant activity, considerable antimicrobial activity against Escherichia coli and Staphylococcus aureus, and considerable cytotoxic activity against brine shrimp. The sulfanilamide degradation was found to be 96.70%, under natural sunlight and in the presence of 0.1% ZnO NPs at pH 10 with a time of 3?h. The dye degradation was found to be 84% under sunlight in the presence of 0.01% ZnO NPs at pH 10 with a time of 40?min. The synthesized ZnO NPs may be explored furthermore in the fields of wastewater treatment, biomedicine, biosensor, and nanotechnology. 相似文献
102.
Reaction of trans-Ru(DMSO)4Cl2 with DMAP (DMAP = 4-dimethylaminopyridine) yields the yellow [Ru(DMAP)6](2+) cation in good yield. The crystal and molecular structure of [Ru(DMAP)6]Cl2.6CH3CH2OH was determined by X-ray diffraction methods. The complex crystallizes in the trigonal R3 space group with a = b = 16.373(1), c = 20.311(1) A, gamma = 120 degrees , and Z = 3 molecules per unit cell. The reaction of [Ru(DMAP)6](2+) in aerobic water gives the red [Ru(III)(DMAP)5(OH)](2+) cation. This complex shows a chemical behavior similar to [Ru(III)(NH3)5Cl](2+) and allows the preparation of a family of [Ru(DMAP)5L](n+) complexes. Their electronic properties indicate that the {Ru(II)(DMAP)5} fragment is a weaker pi-donor than {Ru(II)(NH 3)5}. Our density functional theory (DFT) calculations show that in {Ru(II)(DMAP)5} the DMAP ligands can compete for the pi electron density of the ruthenium making the fragment a weaker pi-donor. 相似文献
103.
Michael A. Morris Alexander Vallmitjana Fabian Grein Tanja Schneider Melina Arts Chelsea R. Jones Betty T. Nguyen Mohammad H. Hashemian Melody Malek Enrico Gratton James S. Nowick 《Chemical science》2022,13(26):7747
Teixobactin has been the source of intensive study and interest as a promising antibiotic, because of its excellent activity against drug-resistant Gram-positive pathogens and its novel but not yet fully understood mechanism of action that precludes drug resistance. Recent studies have demonstrated that the mode of action of teixobactin is more complicated than initially thought, with supramolecular assembly of the antibiotic appearing to play a critical role in the binding process. Further studies of the interactions of teixobactin with bacteria and its molecular targets offer the promise of providing deeper insights into its novel mechanism of action and guiding the design of additional drug candidates and analogues. The current study reports the preparation and study of teixobactin analogues bearing a variety of fluorophores. Structured illumination microscopy of the fluorescent teixobactin analogues with B. subtilis enables super-resolution visualization of the interaction of teixobactin with bacterial cell walls and permits the observation of aggregated clusters of the antibiotic on the bacteria. Förster resonance energy transfer (FRET) microscopy further elucidates the supramolecular assembly by showing that fluorescent teixobactin molecules co-localize within a few nanometers on B. subtilis. Fluorescence microscopy over time with a fluorescent teixobactin analogue and propidium iodide in B. subtilis reveals a correlation between cell death and binding of the antibiotic to cellular targets, followed by lysis of cells. Collectively, these studies provide new insights into the binding of teixobactin to Gram-positive bacteria, its supramolecular mechanism of action, and the lysis of bacteria that follows.FRET microscopy experiments demonstrate supramolecular assembly of teixobactin molecules on Bacillus subtilis, providing further evidence that teixobactin is a supramolecular antibiotic. 相似文献
104.
Pt3Ni stands as one of the most active electrocatalysts for the oxygen reduction reaction (ORR). The activity varies with the morphology of the nanocrystals with a high activity observed for the octahedral shape where only the high density {111} crystallographic planes are exposed. Herein, the synthesis of 6 nm Pt3Ni octahedral nanocrystals with a Pt enriched shell or cuboctahedral nanocrystals with a Ni enriched shell is described. Interestingly, the cuboctahedral nanocrystals display a six-pointed star/skeleton of platinum, which features a very uncommon atomic distribution. In the synthesis, a decrease in the oxygen partial pressure induces the transition from octahedral to cuboctahedral morphology. The octahedral and cuboctahedral nanocrystals both demonstrate high ORR activity (1.1 mA cm−2Pt and 1.2 A mg−1Pt at 0.9 V vs reversible hydrogen electrode (RHE) are the highest values obtained for PtNi-20 and PtNi-15, respectively). After exposure to oxidative conditions in the acidic electrolyte, the cuboctahedral nanoparticles with a pristine Ni-rich skin show a Pt skin and retain their cuboctahedral morphology. 相似文献
105.
106.
Melina E. A. Dilanas Emiel Dobbelaar Charlotte M. Gerischer Dr. Alexander Haseloer Dr. Torsten John Claudia Neumeier 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(44):e202201236
In an interview with Benjamin List, winner of the 2021 Nobel Prize in Chemistry, members of the Young Chemists’ Network (JCF) of the German Chemical Society (GDCh) asked him about his science, his career, and the academic system. Benjamin List, Director at the Max-Planck-Institut für Kohlenforschung in Germany, was awarded the Nobel Prize together with David W. C. MacMillan (Princeton University, USA) for the development of asymmetric organocatalysis. After studying chemistry at the Free University of Berlin, he received his doctorate from Goethe University in Frankfurt. He discovered the amino acid proline to be an efficient catalyst and thus co-founded the field of organocatalysis. In 2016, he received the Gottfried Wilhelm Leibniz Prize, which is considered the most important research award in Germany. 相似文献
107.
Gustavo Amadeu Micke Ana Carolina O. Costa Melina Heller Michelle Barcellos Marcel Piovezan Thiago Caon Marcone Augusto Leal de Oliveira 《Journal of chromatography. A》2009,1216(45):7957-7961
The aim of this study was to develop a fast capillary electrophoresis method for the determination of propranolol in pharmaceutical preparations. In the method development the pH and constituents of the background electrolyte were selected using the effective mobility versus pH curves. Benzylamine was used as the internal standard. The background electrolyte was composed of 60 mmol L−1 tris(hydroxymethyl)aminomethane and 30 mmol L−1 2-hydroxyisobutyric acid, at pH 8.1. Separation was conducted in a fused-silica capillary (32 cm total length and 8.5 cm effective length, 50 μm I.D.) with a short-end injection configuration and direct UV detection at 214 nm. The run time was only 14 s. Three different strategies were studied in order to develop a fast CE method with low total analysis time for propranolol analysis: low flush time (Lflush) 35 runs/h, without flush (Wflush) 52 runs/h, and Invert (switched polarity) 45 runs/h. Since the three strategies developed are statistically equivalent, Wflush was selected due to the higher analytical frequency in comparison with the other methods. A few figures of merit of the proposed method include: good linearity (R2 > 0.9999); limit of detection of 0.5 mg L−1; inter-day precision better than 1.03% (n = 9) and recovery in the range of 95.1–104.5%. 相似文献
108.
Clovis Peppe Fabiano Molinos de Andrade Jaqueline Pinto Vargas Melina de Azevedo Mello Railander Alves Barcellos Robert A. Burrow Rubia Mara Siqueira da Silva 《Journal of organometallic chemistry》2009,694(14):2228-2233
Halogenomethyl-dihalogen-indium(III) compounds X2InCH2X (X = Br, I) obtained from indium monohalides and methylene dihalides were reacted with the soft donor ligands dialkylsulfides, R2S (R = CH3, CH2Ph) to afford the corresponding dialkylsulfonium methylide complexes of InX3, X3InCH2SR2 (X = Br, R = CH3, 1; X = I, R = CH3, 2; X= I, R = CH2Ph, 3). Compound 1 was reacted with the hard donor ligands dimethylsulfoxide or triphenylphosphine oxide to give the corresponding 1:1 adduct, Br3(L)InCH2S(CH3)2 (L = (CH3)2SO, 4; L = (C6H5)3PO, 5). Compounds 1-5 were fully characterized in solution by NMR spectroscopy and in the solid state by X-ray methods. 相似文献
109.
José Alfredo Del-Oso Bernardo Antonio Frontana-Uribe José-Luis Maldonado Margarita Rivera Melina Tapia-Tapia Gabriela Roa-Morales 《Journal of Solid State Electrochemistry》2018,22(7):2025-2037
In this article, controlled changes on morphology, thickness, and band gap of poly[ethylenedioxythiophene] (PEDOT) polymer films fabricated by electrochemical polymerization (potentiostatically) are analyzed. Electropolymerization of the monomer ethylenedioxythiophene (EDOT) was carried out on indium tin oxide (ITO) electrodes, in different dry organic electrolytic media, such as acetonitrile, acetonitrile–dichloromethane, and toluene–acetonitrile mixtures. It was found that electropolymerization kinetics can be controlled by changing the polarity of the electrolytic media, and kinetics is slower for those with low polarity. This fact combined with an accurate control of EDOT monomer concentration and electropolymerization at Epeak/2 potential, allows to control the morphology and thickness of the electropolymerized PEDOT films (E-PEDOT:ClO4); toluene/ACN (4:1, v/v) and [EDOT]?=?0.3 mM gave the best films for application in organic photovoltaic (OPV) cells. The performance of the E-PEDOT:ClO4 films was tested on ITO electrodes as anode buffer layer in OPV cells with the configuration ITO/E-PEDOT:ClO4/P3HT:PC61BM/Field’s metal, where Field’s metal (cathode) is a eutectic alloy that lets to fabricate OPV devices easily and in a fast and economical way at free vacuum conditions. The performance of these devices was compared with an OPV device constructed with a buffer layer anode, prepared using the classical spin coating of PEDOT:PSS on ITO. Results showed that OPV cells fabricated with E-PEDOT:ClO4 have a slightly increased PV performance. 相似文献
110.
A novel blue light-emitting phosphor, Eu2+-doped magnesium strontium aluminate (MgSrAl10O17:Eu2+), for plasma display panel (PDP) application was developed. X-ray diffraction (XRD) patterns disclosed that the phosphor annealed at 1500 °C for 5 h was a pure MgSrAl10O17 phase. Field emission scanning electron microscopy (FE-SEM) images showed the particle size of the phosphor was less than 3 μm. The phosphor shows strong and broad blue emission under vacuum ultraviolet (VUV) light excitation. After baking at 400-600 °C and irradiation with VUV light for 300 h, the phosphor still keep excellent VUV luminescence properties exhibiting good stability against high temperature baking and VUV irradiation. The decay time was short as 1.09 μs and the quantum yield was high to 0.77±0.02. All the characteristics indicated that MgSrAl10O17:Eu2+ would be a promising blue phosphor for PDP application. 相似文献