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1.
Acta Mathematicae Applicatae Sinica, English Series - In this paper, we investigate a delayed HIV infection model that considers the homeostatic proliferation of CD4+ T cells. The existence and... 相似文献
2.
Watanabe Sou Senzaki Tatsuya Shibata Atsuhiro Nomura Kazunori Takeuchi Masayuki Nakatani Kiyoharu Matsuura Haruaki Horiuchi Yusuke Arai Tsuyoshi 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1273-1277
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate... 相似文献
3.
Control of chain ends of polyesters in polycondensation of AA and BB monomers by use of solid‐phase reagent 下载免费PDF全文
Toshihiko Sugiura Daisuke Yajima Kento Shoji Yoshihiro Ohta Tsutomu Yokozawa 《Journal of polymer science. Part A, Polymer chemistry》2015,53(11):1379-1386
For selective synthesis of linear polyester having a functional group at one end, polycondensation between 1,4‐butanediol ( 1a ) and sebacoyl chloride ( 2a ) and between 1,12‐dodecanediol ( 1b ) and isophthaloyl chloride ( 2b ) was conducted in the presence of oxime resin or oxime silica gel, followed by cleavage of the formed polyester from the solid‐phase support with aniline. Matrix‐assisted laser desorption ionization time‐of‐flight mass spectra and 1H NMR spectra of the cleaved polyester showed that the products contained not only polyester with anilide at one end ( poly 1 ), but also polyester with anilides at both ends ( poly 2 ). The product ratio of poly 1 to poly 2 ( poly 1 / poly 2 ) was dependent on monomers, monomer concentration, feed ratio of monomer to oxime moiety in the support, oxime content in the support, reaction solvent, and the nature of the support. Polyester with a high poly 1 / poly 2 ratio of 81/21 and moderate molecular weight (Mn = 1430 g/mol) was obtained by polycondensation of 1b and 2b in the presence of oxime silica gel in dichloromethane. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1379–1386 相似文献
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Daisuke Saito Dr. Tomasz Galica Prof. Dr. Eiji Nishibori Dr. Masaki Yoshida Dr. Atsushi Kobayashi Prof. Dr. Masako Kato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(32):e202200703
The vapochromic single-crystal-to-single-crystal (SCSC) transformation of a highly luminescent PtII complex bearing an N-heterocyclic carbene [Pt(CN)2(tBu-impy)] (tBu-impyH+=1-tert-butyl-3-(2-pyridyl)-1H-imidazolium) is reported. The trihydrate form of the complex, which exhibits blue 3MMLCT emission owing to weak Pt⋅⋅⋅Pt interactions, changed its luminescence color from blue to yellowish-green upon the desorption of water molecules while keeping the high emission quantum yield of more than 0.45. Variable-temperature and continuous in-situ tracking of single-crystal X-ray diffraction measurements revealed that the SCSC transformation proceeds reversibly by the release and reabsorption of water molecules, thereby changing the stacked structure slightly. As a result, the dynamics of vapor-induced SCSC transformation were elucidated: that the anhydrous form returned to the original trihydrate form in a two-step process under a water vapor atmosphere. In addition, the PtII complex exhibited a similar SCSC response accompanied by a luminescence color change in the presence of methanol vapor, while being inactive toward ethanol vapor. 相似文献
6.
Treatment of a meso‐diarylporphyrin with PhI(OAc)2 in the presence of BF3 ? OEt2 and propionic acid affords the corresponding porphyrinquinone in a high yield (91%). A novel quinone derived from meso‐meso β–β doubly‐fused diporphyrin was obtained as the sole byproduct (16% yield), which exhibits strong panchromatic absorption between 300 and 1000 nm. It has a low HOMO‐LUMO gap owing to expanded and low‐symmetry π‐planes. 相似文献
7.
Shaobo Cheng Vidushi Sharma Altug S. Poyraz Lijun Wu Xing Li Amy C. Marschilok Esther S. Takeuchi Kenneth J. Takeuchi Marivi Fernndez-Serra Yimei Zhu 《Chemical science》2020,11(19):4991
Tunneled metal oxides such as α-Mn8O16 (hollandite) have proven to be compelling candidates for charge-storage materials in high-density batteries. In particular, the tunnels can support one-dimensional chains of K+ ions (which act as structure-stabilizing dopants) and H2O molecules, as these chains are favored by strong H-bonds and electrostatic interactions. In this work, we examine the role of water molecules in enhancing the stability of K+-doped α-Mn8O16 (cryptomelane). The combined experimental and theoretical analyses show that for high enough concentrations of water and tunnel-ions, H2O displaces K+ ions from their natural binding sites. This displacement becomes energetically favorable due to the formation of K2+ dimers, thereby modifying the stoichiometric charge of the system. These findings have potentially significant technological implications for the consideration of cryptomelane as a Li+/Na+ battery electrode. Our work establishes the functional role of water in altering the energetics and structural properties of cryptomelane, an observation that has frequently been overlooked in previous studies.Water displaces potassium ions and initiates the formation of a homonuclear dimer ion (K2+) in the tunnels of hollandite. 相似文献
8.
Daisuke Uraguchi Fumito Ueoka Naoya Tanaka Tomohito Kizu Wakana Takahashi Takashi Ooi 《Angewandte Chemie (International ed. in English)》2020,59(28):11456-11461
Catalysis by chiral weakly‐coordinating anions (WCAs) remains underdeveloped due to the lack of a molecular design strategy for exploiting their characteristics, such as the non‐nucleophilic nature. Here, we report the development of a chiral borate ion comprising an O,N,N,O‐tetradentate backbone, which ensures hitherto unattainable structural robustness. Upon pairing with a proton, the hydrogen borate acts as an effective catalyst for the asymmetric Prins‐type cyclization of vinyl ethers, providing access to structurally and stereochemically defined dihydropyrans. The key to selectivity control is the distinct ability of the borate ion to discriminate the prochiral faces of the acyclic oxonium ion intermediate and dictate the regiochemical outcome. We anticipate that this study paves the way for exploring the untapped potential of WCA catalysis for selective chemical synthesis. 相似文献
9.
Haruka Takeuchi Prof. Dr. Shinsuke Inuki Kohei Nakagawa Takaaki Kawabe Dr. Atsuhiko Ichimura Prof. Dr. Shinya Oishi Prof. Dr. Hiroaki Ohno 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21396-21401
We report herein a nonbiomimetic strategy for the total synthesis of the plicamine-type alkaloids zephycarinatines C and D. The key feature of the synthesis is a stereoselective reductive radical ipso-cyclization using visible-light-mediated photoredox catalysis. This cyclization enabled the construction of a 6,6-spirocyclic core structure through the addition of a carbon-centered radical onto the aromatic ring. Biological evaluation of zephycarinatines and their derivatives revealed that the synthetic derivative with a keto group displays moderate inhibitory activity against LPS-induced NO production. This approach could offer future opportunities to expand the chemical diversity of plicamine-type alkaloids as well as providing useful intermediates for their syntheses. 相似文献
10.
Takumi Watanabe Yuichiro Nishizawa Haruka Minato Dr. Chihong Song Prof. Dr. Kazuyoshi Murata Prof. Dr. Daisuke Suzuki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):8934-8938
The three-dimensional structure of nanocomposite microgels was precisely determined by cryo-electron micrography. Several nanocomposite microgels that differ with respect to their nanocomposite structure, which were obtained from seeded emulsion polymerization in the presence of microgels, were used as model nanocomposite materials for cryo-electron micrography. The obtained three-dimensional segmentation images of these nanocomposite microgels provide important insights into the interactions between the hydrophobic monomers and the microgels, that is, hydrophobic styrene monomers recognize molecular-scale differences in polarity within the microgels during the emulsion polymerization. This result led to the formation of unprecedented multi-layered nanocomposite microgels, which promise substantial potential in colloidal applications. 相似文献