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1.
Journal of Fluorescence - This report describes a combined immunofluorescence and fluorescence viability stain applied as one staining solution for rapid detection of live Legionella... 相似文献
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Clément Falaise Dr. May Nyman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14678-14687
For 11 years now, the structural diversity and aesthetic beauty of uranyl–peroxide capsules have fascinated researchers from the diverse fields of mineralogy, polyoxometalate chemistry, and nuclear fuel technologies. There is still much to be learned about the mechanisms of the self‐assembly process, and the role of solution parameters including pH, alkali template, temperature, time, and others. Here we have exploited the high solubility of the UO22+/H2O2/LiOH aqueous system to address the effect of the hydroxide concentration. Important techniques of this study are single‐crystal X‐ray diffraction, small‐angle X‐ray scattering, and Raman spectroscopy. Three key phases dominate the solution speciation as a function of time and the LiOH/UO22+ ratio: the uranyl–triperoxide monomer [UO2(O2)3]4?and the two capsules [(UO2)(O2)(OH)]2424?(U24) and [(UO2)(O2)1.5]2828?(U28). When the LiOH/U ratio is around three, U28 forms rapidly and this cluster can be isolated in high yield and purity. This result was most surprising and challenges the hypothesis that alkali templating is the most important determinant in the cluster geometry. Moreover, analogous experiments with KOH, NH4OH, and TEAOH (TEA=tetraethylammonium) also rapidly yield U28, which suggests that U28 is the kinetically favored species. Complete mapping of the pH–time phase space reveals only a narrow window of the U28 dominance, which is why it was previously overlooked as an important kinetic species in this chemical system, as well as others with different counterions. 相似文献
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Dr. Pere Miró Dr. Bess Vlaisavljevich Dr. Adria Gil Dr. Peter C. Burns Dr. May Nyman Dr. Carles Bo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(25):8571-8578
A wide range of uranyl–peroxide nanocapsules have been synthesized using very simple reactants in basic media; however, little is known about the process to form these species. We have performed a density functional theory study of the speciation of the uranyl ions under different experimental conditions and explored the formation of dimeric species via a ligand exchange mechanism. We shed some light onto the importance of the excess of peroxide and alkali counterions as a thermodynamic driving force towards the formation of larger uranyl–peroxide species. 相似文献
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The mass spectral analysis of metal salts, especially lanthanide and transition metal salts, can be challenging. Although getting information on the metal present is usually straightforward, obtaining information on the correct oxidation state and anion composition is challenging. Many ionisation techniques have some redox component to the ionisation process, which commonly results in changing the oxidation state of the metal and the associated loss of ligand and anion information. We present here a simple method for negative ion matrix‐assisted laser desorption/ionisation mass spectrometry using the non‐acidic flavonoid flavone as a novel matrix. This results in reliable information on the oxidation state of the metal as spectra are dominated by anion adduct ions with very little (typically no) redox processes occurring. 相似文献
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Wei Xu Dr. Karoly Kozma Tianxiang Sha Yi-Jen Wu Prof. May Nyman Prof. Michael M. Lerner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(36):8101-8104
The alkaline earth metals (M=Mg, Ca, Sr, and Ba) exhibit a +2 oxidation state in nearly all known stable compounds, but MI dimeric complexes with M−M bonding, [M2(en)2]2+, (en=ethylenediamine) of all these metals can be stabilized within the galleries of donor-type graphite intercalation compounds (GICs). These metals can also form GICs with more conventional metal (II) ion complexes, [M(en)2]2+. Here, the facile interconversion between dimeric-MI and monomeric-MII intercalates upon the addition/removal of en are reported. Thermogravimetry, powder X-ray diffraction, and pair distribution function analysis of total scattering data support the presence of either [M2(en)2]2+ or [M(en)2]2+ guests. This phase conversion requires coupling graphene and metal redox centers, with associated reversible M−M bond formation within graphene galleries. This chemistry allows the facile isolation of unusual oxidation states, reveals M0→M2+ reaction pathways, and present new opportunities in the design of hybrid conversion/intercalation materials for applications such as charge storage. 相似文献
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Lewis Acid Catalyzed Condensation–Cyclization Cascade: Direct Synthesis of Di/Trifluoromethyl‐1,2,3,4‐tetrahydroquinazolines 下载免费PDF全文
Prof. Dr. G. K. Surya Prakash Dr. Attila Papp Socrates B. Munoz Nathan May John‐Paul Jones Prof. Dr. Ralf Haiges Prof. Dr. Pierre Mothé Esteves Dr. Thomas Mathew 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10170-10178
Condensed heterocycles such as quinazolines constitute the framework of many promising drugs. The great impact of the dramatic fluorine effect in pharmaceuticals prompted a great surge in the quest for fluorinated drug design resulting in over 20 % fluorine‐containing drugs in the market today. Therefore, finding an efficient and cost‐effective method for the direct synthesis of fluorine‐tagged quinazoline systems is of great significance in the pharmaceutical arena. For the first time, a one‐pot sequential condensation–cyclization reaction to form selectively the difluoro/trifluoromethylated tetrahydroquinazolines from simple components difluoro/trifluoroacetaldehyde hemiacetal and aromatic amines is reported. Our recent studies using difluoro/trifluoroacetaldehyde hemiacetal as simple and elegant difluoro/trifluoromethyl synthons and metal triflates such as gallium triflate as safe and stable Lewis acid catalysts led us to this direct synthesis protocol for the expedient and convenient synthesis of fluorinated quinazolines. DFT calculations at PCM/B3LYP/6‐31++G** were carried out for evaluating a possible reaction mechanism for this cyclization. According to the DFT calculations, product stereochemistry is thermodynamically driven, favoring the cis isomer as the major product, which is also confirmed experimentally. 相似文献
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Organocatalyzed Asymmetric Conjugate Addition of Heteroaryl and Aryl Trifluoroborates: a Synthetic Strategy for Discoipyrrole D 下载免费PDF全文
Jiun‐Le Shih Thien S. Nguyen Prof. Jeremy A. May 《Angewandte Chemie (International ed. in English)》2015,54(34):9931-9935
Bis‐heteroaryl or bis‐aryl stereocenters were formed by an organocatalytic enantioselective conjugate addition using the respective trifluoroborate salts as nucleophiles. Control studies suggested that fluoride dissociation is necessary in the anhydrous conditions. This strategy is applicable to the synthesis of discoipyrrole D, an inhibitor of BR5 fibroblast migration. 相似文献