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排序方式: 共有132条查询结果,搜索用时 15 毫秒
1.
The synthesis of an 8-aza-PGE1 analog, (E)-7-[[2-[4-(m-trifluoromethylphenoxy)-3α and 3β-hydroxy-1-butenyl]-5-oxo-pyrrolidinyl]]heptanoic acids is reported. 相似文献
2.
Ritesh Sachan Abhinav Malasi Sagar Yadavali Blake Griffey John Dunlap Gerd Duscher Ramki Kalyanaraman 《Particle & Particle Systems Characterization》2015,32(4):476-482
Currently, one of the challenges in high‐resolution transmission electron microscopy (TEM) studies of nanomaterials is to make contamination‐free materials in a simple and time‐efficient way. Here, a method is demonstrated that combines nanosecond‐pulsed laser dewetting of thin films with a film float‐off technique to realize nanostructures (NSs) on electron‐transparent substrates in a robust and rapid manner. NSs of metal (Ag) and bimetals (AgCo, AuCo) ranging from 20 to 150 nm are synthesized on thin carbon film deposited on mica substrates. The NS/carbon system is subsequently transferred onto TEM grids by a float‐off process resulting from debonding of the carbon from mica due to their contrasting hydrophobic nature. This process enables the fabrication of different NSs on flexible and electron‐transparent substrates. 相似文献
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Dr. Ritesh Haldar Kamal Batra Stefan Michael Marschner Dr. Agnieszka B. Kuc Dr. Stefan Zahn Prof. Dr. Roland A. Fischer Prof. Dr. Stefan Bräse Prof. Dr. Thomas Heine Prof. Dr. Christof Wöll 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(33):7847-7851
In organic photovoltaics, porphyrins (PPs) are among the most promising compounds owing to their large absorption cross-section, wide spectral range, and stability. Nevertheless, a precise adjustment of absorption band positions to reach a full coverage of the so-called green gap has not been achieved yet. We demonstrate that a tuning of the PP Q- and Soret bands can be carried out by using a computational approach for which substitution patterns are optimized in silico. The most promising candidate structures were then synthesized. The experimental UV/Vis data for the solvated compounds were in excellent agreement with the theoretical predictions. By attaching further functionalities, which allow the use of PP chromophores as linkers for the assembly of metal-organic frameworks (MOFs), we were able to exploit packing effects resulting in pronounced redshifts, which allowed further optimization of the photophysical properties of PP assemblies. Finally, we use a layer-by-layer method to assemble the PP linkers into surface-mounted MOFs (SURMOFs), thus obtaining high optical quality, homogeneous and crystalline multilayer films. Experimental results are in full accord with the calculations, demonstrating the huge potential of computational screening methods in tailoring MOF and SURMOF photophysical properties. 相似文献
5.
G. Manasa Arvind K. Bhakta Zineb Mekhalif Ronald J. Mascarenhas 《Electroanalysis》2019,31(7):1363-1372
Increased concern over the risk resorcinol (RS) pose to ecology and humans, led to its position in European Union Category 1 list of endocrine disruptors. Legal measures restricted RS utilization and hence crucial to monitor its levels in the environment. Herein we report development of highly efficient and economically viable electrochemical sensor for quantitative determination of RS based on 77Maghemite/MultiWall Carbon Nanotube (M/MWCNT) modified carbon paste electrode. M/MWCNT was synthesized via strategic IR irradiation for the first time, a promising approach to overcome other complicated chemical routes. Powder X‐ray diffraction (PXRD), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM) and Energy dispersive X‐ray (EDX) were used for characterization. Using Differential Pulse Voltammetry (DPV), we report the lowest detection limit at 0.02 μM. The potential application of the sensor was accomplished as a result of excellent recoveries made from real samples fortified with RS. Results indicated the proficiency of the sensor reliable for rapid, onsite monitoring of RS water contamination and in biological matrices. 相似文献
6.
Ritesh Raju Oleksandr Gromyko Viktor Fedorenko Andriy Luzhetskyy Rolf Müller 《Tetrahedron letters》2012,53(24):3009-3011
A Streptomyces sp. Lv3-13, isolated from the rhizosphere soil of the plant Mespilus germanica, has yielded three new pimprinine derivatives, named pimprinols A–C (1–3) and the unknown (2-aminophenyl)(2-ethyloxazol-5-yl) methanone (4) along with the known compounds 2-ethyl oxazole pimprinine and 2-propyl oxazole pimprinine. The structures of the compounds were elucidated based on spectroscopic methods including UV, HR-ESIMS and 1D, 2D NMR data. Compounds 1–4 were screened for antimicrobial and cytotoxic activities. 相似文献
7.
Combinatorial Crystal Synthesis: Structural Landscape of Phloroglucinol:1,2‐bis(4‐pyridyl)ethylene and Phloroglucinol:Phenazine 下载免费PDF全文
Ritesh Dubey Prof. Gautam R. Desiraju 《Angewandte Chemie (International ed. in English)》2014,53(48):13178-13182
A large number of crystal forms, polymorphs and pseudopolymorphs, have been isolated in the phloroglucinol‐dipyridylethylene (PGL:DPE) and phloroglucinol‐phenazine (PGL:PHE) systems. An understanding of the intermolecular interactions and synthon preferences in these binary systems enables one to design a ternary molecular solid that consists of PGL, PHE, and DPE, and also others where DPE is replaced by other heterocycles. Clean isolation of these ternary cocrystals demonstrates synthon amplification during crystallization. These results point to the lesser likelihood of polymorphism in multicomponent crystals compared to single‐component crystals. The appearance of several crystal forms during crystallization of a multicomponent system can be viewed as combinatorial crystal synthesis with synthon selection from a solution library. The resulting polymorphs and pseudopolymorphs that are obtained constitute a crystal structure landscape. 相似文献
8.
Apurba Bhattacharya Nitin C. Patel Ritesh Tichkule Jiejun Wu 《Tetrahedron letters》2006,47(4):565-567
A simple, surfactant-mediated, one-pot, solvent-free dealkylative cleavage of aryl ethers and esters followed by subsequent optional trans-alkylation under essentially neutral conditions has been developed. 相似文献
9.
Chemical analysis of a marine-derived Streptomyces sp. (CMB-M0423) isolated from beach sand off Heron Island, Australia, yielded three new members of the rare pyrroloterpene biosynthetic structure class. Identified by detailed spectroscopic analysis as the first reported examples of naturally occurring 2-nitropyrroles, heronapyrroles A-C (1-3) displayed promising biological activity-with low to submicromolar IC(50) activity against Gram-positive bacteria but no cytotoxicity toward mammalian cell lines. 相似文献
10.
We revisit the well-known topics of self- and induced-screening in an otherwise isotropic neutral plasma/colloid. It is pointed out that the standard Debye-Hückel (DH) theory (ignoring finite size effects) suffers from many ambiguities related to net ionic numbers, total charge of the system, role of the electrostatic Gauss law, short-distance behaviour of the potential and incorrectly normalized pair correlation functions. We give a new formulation (incorporating finite size effects) such that ionic numbers are maintained, the total charge of the system has physically correct value, the Gauss law boundary conditions are rigorously obeyed, short-distance behaviour of the potential is guaranteed automatically, and correlation functions are correctly normalized. Numerical differences between the two approaches show up if the screening length μ−1 becomes comparable to the size R of the system. 相似文献