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81.
Dr. Carlos Sánchez-Sánchez Dr. Thomas Dienel Dr. Adrien Nicolaï Dr. Neerav Kharche Dr. Liangbo Liang Colin Daniels Prof. Vincent Meunier Dr. Junzhi Liu Prof. Xinliang Feng Prof. Klaus Müllen Dr. Juan Ramón Sánchez-Valencia Dr. Oliver Gröning Dr. Pascal Ruffieux Prof. Roman Fasel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(52):12074-12082
A bottom up method for the synthesis of unique tetracene-based nanoribbons, which incorporate cyclobutadiene moieties as linkers between the acene segments, is reported. These structures were achieved through the formal [2+2] cycloaddition reaction of ortho-functionalized tetracene precursor monomers. The formation mechanism and the electronic and magnetic properties of these nanoribbons were comprehensively studied by means of a multitechnique approach. Ultra-high vacuum scanning tunneling microscopy showed the occurrence of metal-coordinated nanostructures at room temperature and their evolution into nanoribbons through formal [2+2] cycloaddition at 475 K. Frequency-shift non-contact atomic force microscopy images clearly proved the presence of bridging cyclobutadiene moieties upon covalent coupling of activated tetracene molecules. Insight into the electronic and vibrational properties of the so-formed ribbons was obtained by scanning tunneling microscopy, Raman spectroscopy, and theoretical calculations. Magnetic properties were addressed from a computational point of view, allowing us to propose promising candidates to magnetic acene-based ribbons incorporating four-membered rings. The reported findings will increase the understanding and availability of new graphene-based nanoribbons with high potential in future spintronics. 相似文献
82.
Erika Alejandra Martínez-Ortega José Sergio López-Briones Gabriela Rodríguez-Hernández Ricardo Ernesto Ramírez-Orozco 《Natural product research》2020,34(18):2639-2641
AbstractThe objective of this study was to evaluate the antimicrobial effect of Agave fructans against the Salmonella Typhimurium in “in vitro” experiments. The result of the antimicrobial activity was 263.89?±?0, 414.95?±?12.83, 494.54?±?13.88, 522.29?±?0, 580.41?±?14.92?AU for 10, 20, 30, 40 and 50% of Agave fructans (AF) respectively. In addition, there is a significant effect on the growth of the bacteria with all the percentages of AF evaluated (p?<?0.001, R2?=?0.859) with respect to the control. The growth rate of Salmonella with 25% AF was statistically significant compared to the control (?0.7353?±?0.586, 0.0079?±?0.002?D.O./h, respectively; p?>?0.01). Agave fructans could be an alternative to prevent the infections caused by Salmonella. 相似文献
83.
A Quantitative Model for Alkane Nucleophilicity Based on C−H Bond Structural/Topological Descriptors
84.
Tomáš Hložek Martin Štícha Miroslava Bursová Ivan Jelínek Petr Tůma Radomír Čabala 《Electrophoresis》2020,41(18-19):1564-1567
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR. 相似文献
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Nováková Kateřina Hrdlička Vojtěch Navrátil Tomáš Vyskočil Vlastimil Barek Jiří 《Monatshefte für Chemie / Chemical Monthly》2015,146(5):761-769
Monatshefte für Chemie - Chemical Monthly - The voltammetric behavior of 5-nitroindazole was investigated at polished (p-AgSAE) and at mercury meniscus-modified (m-AgSAE) silver solid amalgam... 相似文献
87.
Formation of porous polymer morphology by microsyneresis during divinylbenzene polymerization 下载免费PDF全文
Libuše Hanková Ladislav Holub Karel Jeřábek 《Journal of Polymer Science.Polymer Physics》2015,53(11):774-781
This article describes the investigation of the importance of various reaction conditions on microsyneretic pore formation during polymerization of divinylbenzene (DVB) under so‐called “solvothermal” conditions. To induce microsyneretic pore formation, the most important parameter is an unusually high dilution of monomers with a “good” porogen solvating the polymer chains. High dilution and solvation of the growing poly(DVB) chains promote the prolongation of the polymer chains rather than their interconnection by crosslinking. Consequently, when the polymer gel density reaches the point where syneresis starts, the polymer network is geometrically too extensive to be broken up into precipitating entities and, instead, porogen droplets are formed within the continuous polymer gel. The pore geometry created by microsyneresis offers high surface area in wide mesopores and hence, high capacity for supporting functional groups or reactions with much better accessibility than narrow pores between polymer microspheres produced by macrosyneresis in conventional styrenic polymer supports. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 774–781 相似文献
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