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排序方式: 共有382条查询结果,搜索用时 15 毫秒
311.
Dr. Christoph Wallach M. Sc. Yasmin Selic Dr. Felix S. Geitner Ajeet Kumar Dr. Erling Thyrhaug Prof. Dr. Jürgen Hauer Prof. Dr. Antti J. Karttunen Prof. Dr. Thomas F. Fässler 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304088
C60 donor dyads in which the carbon cage is covalently linked to an electron-donating unit have been discussed as one possibility for an electron-transfer system, and it has been shown that spherical [Ge9] cluster anions show a close relation to fullerenes with respect to their electronic structure. However, the optical properties of these clusters and of functionalized cluster derivatives are almost unknown. We now report on the synthesis of the intensely red [Ge9] cluster linked to an extended π-electron system. [Ge9{Si(TMS)3}2{CH3C=N}-DAB(II)Dipp]− ( 1− ) is formed upon the reaction of [Ge9{Si(TMS)3}2]2− with bromo-diazaborole DAB(II)Dipp-Br in CH3CN (TMS=trimethylsilyl; DAB(II)=1,3,2-diazaborole with an unsaturated backbone; Dipp=2,6-di-iso-propylphenyl). Reversible protonation of the imine entity in 1− yields the deep green, zwitterionic cluster [Ge9{Si(TMS)3}2{CH3C=N(H)}-DAB(II)Dipp] ( 1-H ) and vice versa. Optical spectroscopy combined with time-dependent density functional theory suggests a charge-transfer excitation between the cluster and the antibonding π* orbital of the imine moiety as the cause of the intense coloration. An absorption maximum of 1-H in the red region of the electromagnetic spectrum and the corresponding lowest-energy excited state at λ=669 nm make the compound an interesting starting point for further investigations targeting the design of photo-active cluster compounds. 相似文献
312.
UO2F2 abstracts F− anions from TlF in liquid ammonia solution and the compound [Tl2(NH3)6][{UO2F2(NH3)}2(μ-F)2] is formed. The compound has been characterized by single crystal X-ray diffraction, Raman spectroscopy and quantum-chemical calculations for the solid state. Quantum-chemical investigation of the [{UO2F2(NH3)}2(μ-F)2]2− anion showed that the U−(μ-F)−U σ-3c-4e-bond is essentially ionic. The [Tl2(NH3)6]2+ cation shows a thallophilic Tl⋅⋅⋅Tl interaction. Fluoride ion affinities (FIAs) were calculated for different UO22+ species [UO2Fx]2−x and [UO2Fx(NH3)5−x]2−x with x=0 to 4. 相似文献
313.
Santosh Kumar Adla Arun Kumar Tonduru Thales Kronenberger Eva Kudova Antti Poso Kristiina M. Huttunen 《Molecules (Basel, Switzerland)》2021,26(18)
In this study, we investigated the delivery of synthetic neurosteroids into MCF-7 human breast adenocarcinoma cells via Organic Anionic Transporting Polypeptides (OATPs) (pH 7.4 and 5.5) to identify the structural components required for OATP-mediated cellular uptake and to get insight into brain drug delivery. Then, we identified structure-uptake relationships using in-house developed OATP1A2 homology model to predict binding sites and modes for the ligands. These binding modes were studied by molecular dynamics simulations to rationalize the experimental results. Our results show that carboxylic acid needs to be at least at 3 carbon-carbon bonds distance from amide bond at the C-3 position of the androstane skeleton and have an amino group to avoid efflux transport. Replacement of hydroxyl group at C-3 with any of the 3, 4, and 5-carbon chained terminal carboxylic groups improved the affinity. We attribute this to polar interactions between carboxylic acid and side-chains of Lys33 and Arg556. The additional amine group showed interactions with Glu172 and Glu200. Based on transporter capacities and efficacies, it could be speculated that the functionalization of acetyl group at the C-17 position of the steroidal skeleton might be explored further to enable OAT1A2-mediated delivery of neurosteroids into the cells and also across the blood-brain barrier. 相似文献
314.
Juha Kekkonen Antti Laukkanen Per Stenius Heikki Tenhu 《Colloids and surfaces. A, Physicochemical and engineering aspects》2001,190(3):305-318
The objective of this study is to understand how adsorbed synthetic polymers affect deposition kinetics of dissolved and colloidal wood materials. The synthetic polymers were characterised by means of static and dynamic light scattering, and their adsorption on silica was studied by means of optical reflectometry. Deposition kinetics of colloidal wood resin, compounds in model process water, as well as adsorption of anionic carbohydrates was then studied on the surface layers formed by synthetic polymers. It was found that neither wood resin nor anionic carbohydrates have affinity for adsorbed polyethylene oxide. However, wood resin deposited readily on adsorbed cationic polyacryl amides. Both polyethylene oxide and cationic polyacryl amides formed multilayers with compounds in the model process water. 相似文献
315.
We prove stability of the kink solution of the Cahn‐Hilliard equation ∂tu = ∂( ∂u − u/2 + u3/2), x ∈ ℝ. The proof is based on an inductive renormalization group method, and we obtain detailed asymptotics of the solution as t → ∞. We prove stability of the kink solution of the Cahn‐Hilliard equation ∂tu = ∂( ∂u − u/2 + u3/2), x ∈ ℝ. The proof is based on an inductive renormalization group method, and we obtain detailed asymptotics of the solution as t → ∞. © 1999 John Wiley & Sons, Inc. 相似文献
316.
Jacob Matthan Antti Uusimki Heikki Torvela Seppo Leppvuori 《Macromolecular Symposia》1988,22(1):161-190
A broad review of the field of applications of electroactive polymers, defined as inherently conductive, charged, piezoelectric and pyroelectric, and systems made electroactive by addition of conductive additives, in the field of electronics and microelectronics. Applications mentioned include the use of polymers for electrodes for rechargeable batteries, electret microphones, hydrophones, vidicons, EMI and ESD protection, and conductor and resistor tracks as thick films on printed circuit boards. Future trends as the development of supermolecular assemblies for parallel processing are also highlighted. 相似文献
317.
Dipl.-Chem. H. Lars Deubner Malte Sachs Jascha Bandemehr Dr. Sergei I. Ivlev Prof. Dr. Antti J. Karttunen Stefan R. Kachel Benedikt P. Klein Lukas Ruppenthal Maik Schöniger Claudio K. Krug Jan Herritsch Prof. Dr. J. Michael Gottfried Jamal N. M. Aman Prof. Dr. Jörn Schmedt auf der Günne Prof. Dr. Florian Kraus 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(68):15656-15661
The binary lead fluoride Pb3F8 was synthesized by the reaction of anhydrous HF with Pb3O4 or by the reaction of BrF3 with PbF2. The compound was characterized by single-crystal and powder X-ray diffraction, IR, Raman, and solid-state MAS 19F NMR spectroscopy, as well as thermogravimetric analysis, XP and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Solid-state quantum-chemical calculations are provided for the vibrational analyses and band assignments. The electronic band structure offers an inside view of the mixed valence compound. 相似文献
318.
Leskinen Anumaija Salminen-Paatero Susanna Räty Antti Tanhua-Tyrkkö Merja Iso-Markku Taneli Puukko Esa 《Journal of Radioanalytical and Nuclear Chemistry》2020,323(1):399-413
Journal of Radioanalytical and Nuclear Chemistry - Determination of 14C, 55Fe, 63Ni and gamma emitters in two different types of activated reactor pressure vessel (RPV) steel samples were carried... 相似文献
319.
Muckenhoupt Ap-properties of Distance Functions and Applications to Hardy–Sobolev -type Inequalities
Dyda Bartłomiej Ihnatsyeva Lizaveta Lehrbäck Juha Tuominen Heli Vähäkangas Antti V. 《Potential Analysis》2019,50(1):83-105
Potential Analysis - Let X be a metric space equipped with a doubling measure. We consider weights w(x) = dist(x,E)?α, where E is a closed set in X and $\alpha \in \mathbb {R}$ . We... 相似文献
320.
Barbara Zanfrognini Chiara Zanardi Fabio Terzi Timo ??ritalo Antti Viinikanoja Jukka Lukkari Renato Seeber 《Journal of Solid State Electrochemistry》2011,15(11-12):2395-2400
Multilayers consisting of a water soluble polythiophene derivative and Au nanoparticles have been deposited onto different electrode substrates by means of layer-by-layer deposition technique. The assembly of the films has been performed by taking advantage of the electrostatic interactions between the positively charged imidazolic moiety of the polythiophene chain and the negative charges of citrate ions surrounding Au nanoparticles, as well of the affinity of S to Au. The nanoparticles result stably grafted to the organic matrix. The resulting modified electrodes have been characterised through electrochemical, spectroelectrochemical and microscopic techniques. The results evidenced that a high number of individual nanoparticles is present inside the multilayer. The presence of nanoparticles is of chief importance for most effective charge percolation through the multilayer, as suggested by the responses to electroactive probe species in solution. The electrocatalytic performances of the modified electrodes have been tested with respect to the oxidation of ascorbic acid. 相似文献