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排序方式: 共有1550条查询结果,搜索用时 31 毫秒
941.
942.
Vclav Nmec Michaela Hylsov Luk Maier Jana Flegel Sonja Sievers Slava Ziegler Martin Schrder Benedict‐Tilman Berger Apirat Chaikuad Barbora Val
íkov Stjepan Uldrijan Stanislav Drpela Karel Sou
ek Herbert Waldmann Stefan Knapp Kamil Paruch 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1074-1078
Reported is the identification of the furo[3,2‐b]pyridine core as a novel scaffold for potent and highly selective inhibitors of cdc‐like kinases (CLKs) and efficient modulators of the Hedgehog signaling pathway. Initially, a diverse target compound set was prepared by synthetic sequences based on chemoselective metal‐mediated couplings, including assembly of the furo[3,2‐b]pyridine scaffold by copper‐mediated oxidative cyclization. Optimization of the subseries containing 3,5‐disubstituted furo[3,2‐b]pyridines afforded potent, cell‐active, and highly selective inhibitors of CLKs. Profiling of the kinase‐inactive subset of 3,5,7‐trisubstituted furo[3,2‐b]pyridines revealed sub‐micromolar modulators of the Hedgehog pathway. 相似文献
943.
944.
945.
Iwona Kuźniarska‐Biernacka Otilia Rodrigues Maria A. Carvalho Isabel C. Neves António M. Fonseca 《应用有机金属化学》2012,26(1):44-49
An encapsulated Mn(III)–salen complex in NaY was synthesized and characterized, and the catalytic behaviour of the complex was evaluated by the oxidation of styrene. The encapsulation was achieved by two different methodologies designated as the flexible ligand method (A) and the method of in situ complex synthesis (B). The characterizations of the free complex as well as the catalysts with and without the complex were performed by powder X‐ray diffraction, scanning electron microscopy, chemical analysis and FT‐IR spectroscopy. Both prepared catalysts are active in the oxidation of styrene in the presence of tert‐butyl hydroperoxide (tBuOOH) and lead to styrene epoxide and benzaldehyde. The localization of the complex in zeolite plays an important role in the catalytic activity of these heterogeneous catalysts. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
946.
Hoyoul Kong Shinuk Cho Dong Hoon Lee Nam Sung Cho Moo‐Jin Park In Hwan Jung Jong‐Hwa Park Chan Eon Park Hong‐Ku Shim 《Journal of polymer science. Part A, Polymer chemistry》2011,49(13):2886-2898
A series of new polythiophene derivatives containing a thiazole ring as an electron deficient unit were successfully synthesized via Stille coupling reactions. Synthesized polymers were classified into two types (H‐shape packing and A‐shape packing) based on their interdigitated packing structure induced by different side chain configurations. The thiophene derivatives that contained a thiazole unit ( PT50Tz50 , PTz100 , and PTTz ) exhibited much better thermal stability than did the full thiophene polymers ( PT100 and PTT ). The polymers containing the thiazole unit ( PTz100 and PTTz ) showed a red‐shifted absorption spectrum with clear vibronic structure. In addition, the XRD and AFM results showed that the polymers containing the thiazole unit and interdigitated H‐shape exhibited much better ordered and connected intermolecular structures than did other polymers. The improved intermolecular ordering and surface morphologies directly facilitated charge carrier transport in thin film transistor (TFT) devices, without introducing charge traps, and yielded higher solar cell performance. Among these polymers, the PTTz copolymer exhibited the best TFT performance (μ = 0.050 cm2 V?1 s?1, on/off ratio = 106, and Vth = ?2 V) and solar cell performance (PCE = 1.39%, Jsc = 6.58 mA cm?2, and Voc = 0.58 V). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
947.
Kamil A. Khan 《Optimization》2019,68(2-3):691-711
ABSTRACTIn the spirit of the Whitney Extension Theorem, consider a function on a compact subset of Euclidean space to be ‘Whitney-differentiable’ if it is a restriction of a continuously Fréchet-differentiable function with an open domain. Whitney-differentiable functions have been shown to have useful (yet possibly nonunique) derivatives and calculus properties even on the boundaries of their domains. This article shows that optimal-value functions for bound-constrained convex programmes with Whitney-differentiable objective functions are themselves Whitney-differentiable, even when the linear-independence constraint qualification is not satisfied. This result extends classic sensitivity results for convex programmes, and generalizes recent work. As an application, sufficient conditions are presented for generating continuously differentiable convex underestimators of nonconvex functions for use in methods for deterministic global optimization in the multivariate McCormick framework. In particular, the main result is applied to generate Whitney-differentiable convex underestimators for quotients of functions with known Whitney-differentiable relaxations. 相似文献
948.
Prof. Dr. Šimon Budzák Justina Jovaišaitė Prof. Dr. Chung-Yang Huang Dr. Paulius Baronas Kamilė Tulaitė Prof. Dr. Saulius Juršėnas Prof. Dr. Denis Jacquemin Prof. Dr. Stefan Hecht 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(26):e202200496
N,N′-disubstituted indigos are photoswitchable molecules that have recently caught the attention due to their addressability by red-light. When alkyl and aryl groups are utilized as the N-substituents, the thermal half-lives of Z isomers can be tuned independently while maintaining the advantageous red-shifted absorption spectra. To utilize these molecules in real-world applications, it is of immense importance to understand how their molecular structures as well as the environment influence their switching properties. To this end, we probed their photoisomerization mechanism by carrying out photophysical and computational studies in solvents of different polarities. The fluorescence and transient absorption experiments suggest for more polar excited and transition states, which explains the bathochromic shifts of absorption spectra and shorter thermal half-lives. On the other hand, the quantum chemical calculations reveal that in contrast to N-carbonyl groups, N-alkyl and N-aryl substituents are not strongly conjugated with the indigo chromophore and can thus serve as a tool for tuning the thermal stability of Z isomers. Both approaches are combined to provide in-depth understandings of how indigos undergo photoswitching as well as how they are influenced by N-substituent and the chemical surroundings. These mechanistic insights will serve as guiding principles for designing molecules eyeing broader applications. 相似文献
949.
Kamil Kotwica Anastasia S. Kostyuchenko Dr. Przemyslaw Data Dr. Tomasz Marszalek Lukasz Skorka Dr. Tomasz Jaroch Sylwia Kacka Prof. Malgorzata Zagorska Prof. Robert Nowakowski Prof. Andrew P. Monkman Prof. Alexander S. Fisyuk Prof. Wojciech Pisula Prof. Adam Pron 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11795-11806
Star‐shaped conjugated molecules, consisting of a benzene central unit symmetrically trisubstituted with either oxa‐ or thiadiazole bithiophene groups, were synthesized as promising molecules and building blocks for application in (opto)electronics and electrochromic devices. Their optical (Eg(opt)) as well as electrochemical (Eg(electro)) band gaps depended on the type of the side arm and the number of solubilizing alkyl substituents. Oxadiazole derivatives showed Eg(opt) slightly below 3 eV and by 0.2 eV larger than those determined for thiadiazole‐based compounds. The presence of alkyl substituents in the arms additionally lowered the band gap. The obtained compounds were efficient electroluminophores in guest/host‐type light‐emitting diodes. They also showed a strong tendency to self‐organize in monolayers deposited on graphite, as evidenced by scanning tunneling microscopy. The structural studies by X‐ray scattering revealed the formation of supramolecular columnar stacks in which the molecules were organized. Differences in macroscopic alignment in the specimen indicated variations in the self‐assembly mechanism between the molecules. The compounds as trifunctional monomers were electrochemically polymerized to yield the corresponding polymer network. As shown by UV/Vis‐NIR spectroelectrochemical studies, these networks exhibited reversible electrochromic behavior both in the oxidation and in the reduction modes. 相似文献
950.
Aaron C. Jackson Jonathan A. Bartelt Kamil Marczewski Nancy R. Sottos Paul V. Braun 《Macromolecular rapid communications》2011,32(1):82-87
A generalized silica coating scheme is used to functionalize and protect sub‐micron and micron size dicyclopentadiene monomer‐filled capsules and polymer‐protected Grubbs' catalyst particles. These capsules and particles are used for self‐healing of microscale damage in an epoxy‐based polymer. The silica layer both protects the capsules and particles, and limits their aggregation when added to an epoxy matrix, enabling the capsules and particles to be dispersed at high concentrations with little loss of reactivity.