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11.
A facile synthetic path to isoindolobenzazepine alkaloids, lennoxamine, 13-deoxychilenine, and chilenine, was established by employing a palladium-catalyzed intramolecular α-arylation of the ketone, as the key step. 相似文献
12.
The dark reaction of NOx and H2O vapor in 1 atm of air was studied for the purpose of elucidating the recently discussed unknown radical source in smog chambers. Nitrous acid and nitric oxide were found to be formed by the reaction of NO2 and H2O in an evacuable and bakable smog chamber. No nitric acid was observed in the gas phase. The reaction is not stoichiometric and is thought to be a heterogeneous wall reaction. The reaction rate is first order with respect to NO2 and H2O, and the concentrations of HONO and NO initially increase linearly with time. The same reaction proceeds with a different rate constant in a quartz cell, and the reaction of NO2 and H218O gave H18ONO exclusively. Taking into consideration the heterogeneous reaction of NO2 and H2O, the upper limit of the rate constant of the third-order reaction NO + NO2 + H2O → 2HONO was deduced to be (3.0 ± 1.4) × 10?10 ppm?2-min?1, which is one order of magnitude smaller than the previously reported value. Nitrous acid formed by the heterogeneous dark reaction of NO2 and H2O should contribute significantly to both an initially present HONO and a continuous supply of OH radicals by photolysis in smog chamber experiments. 相似文献
13.
Kazuo Sakamaki Wataru Takahashi 《Journal of Mathematical Analysis and Applications》1979,70(2):445-459
In this paper, we shall prove some results related to doubly-stochastic operators and invariant measures which may be obtained from a general condition by Fan (Math. Z. 68 (1957), 205–217) for the existence of solutions of general systems of convex inequalities in topological vector spaces. 相似文献
14.
Ferrocene‐Substituted Naphthalenediimide with Broad Absorption and Electron‐Transport Properties in the Segregated‐Stack Structure 下载免费PDF全文
Dr. Atsuro Takai Dr. Daisuke Sakamaki Prof. Dr. Shu Seki Dr. Yoshitaka Matsushita Dr. Masayuki Takeuchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(22):7385-7388
A new naphthalenediimide (NDI) molecule, where two ferrocene (Fc) units were directly attached to both imide nitrogens ( Fc‐NDI‐Fc ), was synthesized. The Fc units provide high crystallinity to Fc‐NDI‐Fc with good solubility to conventional organic solvents. The Fc units also work as electron‐donating substituents, in contrast to the electron‐deficient NDI unit, resulting in broad charge‐transfer absorption of Fc‐NDI‐Fc from the UV region to 1500 nm in the solid state. The crystal structure analysis revealed that Fc‐NDI‐Fc formed a segregated‐stack structure. The DFT calculation based on the crystal structure showed that the NDI π‐orbitals extended over two axes. The extended π‐network of the NDI units led to the electron‐transport properties of Fc‐NDI‐Fc , which was confirmed using a flash‐photolysis time‐resolved microwave conductivity technique. 相似文献
15.
N‐Substituted Dicyanomethylphenyl Radicals: Dynamic Covalent Properties and Formation of Stimuli‐Responsive Cyclophanes by Self‐Assembly 下载免费PDF全文
Toshiyuki Kobashi Dr. Daisuke Sakamaki Prof. Dr. Shu Seki 《Angewandte Chemie (International ed. in English)》2016,55(30):8634-8638
Dynamic covalent bonds and their chemistry have been of particular interest both from a fundamental and materials science aspect. Demonstrated herein is that triphenylamine (TPA) and carbazole (Cz), substituted with a dicyanomethyl radical, are useful motifs for dynamic covalent chemistry as they have the appropriate bond strength between monomer units as well as high stability and synthetic simplicity. TPA and Cz units substituted by two dicyanomethyl radicals formed macrocyclic oligomers classified as novel types of azacyclophanes, and in particular, the TPA‐based diradical gave a cyclic dimer in almost quantitative yield. The cyclic oligomers exhibited thermo‐ and mechanochromic behavior resulting from the generation of radical species by intermonomer C?C bond cleavage. 相似文献
16.
Orgiani P Aruta C Balestrino G Born D Maritato L Medaglia PG Stornaiuolo D Tafuri F Tebano A 《Physical review letters》2007,98(3):036401
The metal-insulator transition (MIT) has been studied in Ba(0.9)Nd(0.1)CuO(2+x)/CaCuO2 ultrathin cuprate structures. Such structures allow for the direct measurement of the 2D sheet resistance R( square), eliminating ambiguity in the definition of the effective thickness of the conducting layer in high temperature superconductors. The MIT occurs at room temperature for experimental values of R(square) close to the 25.8 kOmega universal quantum resistance. All data confirm the assumption that each CaCuO2 layer forms a 2D superconducting sheet within the superconducting block, which can be described as weak-coupled equivalent sheets in parallel. 相似文献
17.
Y Yokoyama D Sakamaki A Ito K Tanaka M Shiro 《Angewandte Chemie (International ed. in English)》2012,51(37):9403-9406
The redox properties and electronic structures of polycationic species were examined using a triphenylamine double-decker species. The double-decker has a strong electron-donating ability, and the spin in the radical cation is delocalized over the whole caged skeleton, despite no direct transannular π-π interaction between two TPA decks. Moreover, the diradical dication has spin-singlet character, despite the meta-phenylene linkage. 相似文献
18.
Masurier N Aruta R Gaumet V Denoyelle S Moreau E Lisowski V Martinez J Maillard LT 《The Journal of organic chemistry》2012,77(7):3679-3685
A series of 20 optically pure 3,4-dihydro-5H-pyrido[1',2':1,2]imidazo[4,5-d][1,3]diazepin-5-ones which form a new family of azaheterocycle-fused [1,3]diazepines were synthesized in four steps with 17-66% overall yields. The key step consists of a selective C-acylation reaction of easily accessible 2-aminoimidazo[1,2-a]pyridine at C-3. 相似文献
19.
Back Cover: A Facile and Versatile Approach to Double N‐Heterohelicenes: Tandem Oxidative CN Couplings of N‐Heteroacenes via Cruciform Dimers (Angew. Chem. Int. Ed. 18/2015) 下载免费PDF全文
20.