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991.
Hideki Abe Haruhito Tango Toyoharu Kobayashi Hisanaka Ito 《Tetrahedron letters》2017,58(45):4296-4298
The first total synthesis of the azaphilone derivative, felinone A, was accomplished. The absolute configuration of natural felinone A was revised to be 3S, 6S, and 7R. 相似文献
992.
Dr. Maxim V. Mikhailenko Dr. Salavat S. Khasanov Prof. Alexader F. Shestakov Dr. Aleksey V. Kuzmin Akihiro Otsuka Hideki Yamochi Hiroshi Kitagawa Dr. Dmitri V. Konarev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(10):e202104165
Hexaazatrianthracene (HATA) and hexaazatriphenylenehexacarbonitrile {HAT(CN)6} are reduced by metallic iron in the presence of crystal violet (CV+)(Cl−). Anionic ligands are produced, which simultaneously coordinate three FeIICl2 to form (CV+)2{HATA ⋅ (FeIICl2)3}2− ⋅ 3 C6H4Cl2 ( 1 ) and (CV+)3{HAT(CN)6. (FeIICl2)3}3− ⋅ 0.5CVCl ⋅ 2.5 C6H4Cl2 ( 2 ). High-spin (S=2) FeII atoms in both structures are arranged in equilateral triangles at a distance of 7 Å. An antiferromagnetic exchange is observed between FeII in {HATA ⋅ (FeIICl2)3}2− ( 1 ) with a Weiss temperature (Θ) of −80 K, the PHI estimated exchange interaction (J) is −4.7 cm−1. The {HAT(CN)6 ⋅ (FeIICl2)3}3− assembly is obtained in 2 . The formation of HAT(CN)6.3− is supported by the appearance of an intense EPR signal with g=2.0037. The magnetic behavior of 2 is described by a strong antiferromagnetic coupling between the FeII and HAT(CN)6.3− spins with J1=−164 cm−1 (−2 J formalism) and by a weaker antiferromagnetic coupling between the FeII spins with J2=−15.4 cm−1. The stronger coupling results in the spins of the three FeIICl2 units to be aligned parallel to each other in the assembly. As a result, an increase of the χMT values is observed with the decrease of temperature from 9.82 at 300 K up to 15.06 emu ⋅ K/mol at 6 K, and the Weiss temperature is also positive being at +23 K. Thus, a change in the charge and spin state of the HAT-type ligand to ⋅3− results in ferromagnetic alignment of the FeII spins, yielding a high-spin (S=11/2) system. DFT calculations showed that, due to the high symmetry and nearly degenerated LUMO of both HATA and HAT(CN)6, their complexes with FeIICl2 have a variety of closely lying excited high-spin states with multiplicity up to S=15/2. 相似文献
993.
994.
995.
Hayashi Yui Takada Noriharu Wahyudiono Kanda Hideki Goto Motonobu 《Research on Chemical Intermediates》2017,43(7):4201-4211
Research on Chemical Intermediates - Water–dispersible carbon nanocapsules were synthesized in a one-step process by a pulsed arc discharge over glycine solution under pressurized argon.... 相似文献
996.
Dr. Eugenio Hernán Otal Prof. Dr. Hideki Tanaka Dr. Manuela Leticia Kim Prof. Dr. Juan Paulo Hinestroza Prof. Dr. Mutsumi Kimura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(26):7376-7382
The development of portable, reliable, and low-cost sensors for assessing the quality of natural water sources is of high relevance in developing countries as they can serve as an intermediate solution prior to the building of permanent potable water distribution infrastructure. These sensors should be simple to operate by non-trained operators and easy to manufacture locally. Lanthanide-based metal–organic frameworks (MOFs) offer a trustable platform due to their intense emission in regions of the visible spectra and their high sensitivity to fluorides in water. Cotton was chosen as a substrate due to its high hydrophilicity which, together with the highly porous nature of the MOF, allows for shorter reaction times. The modified cotton was characterized by XRD, SEM as well as XAFS, hence probing the presence of [Tb(BTC)6(H2O)] (Tb-BTC) attachment to cotton. Changes in the emission when Tb-BTC modified cotton was exposed to water and aqueous fluoride solutions were monitored as a function of time. Crystalline phase changes were identified that correlated to structural information. Finally, the Tb-BTC modified cotton was used to build a fluoride demonstrator sensor with a linear response of up to 10 mg L−1 and a limit of detection of 0.8 mg L−1, making it suitable for drinking water analysis under international regulations. 相似文献
997.
Takamasa Oguchi Kazuhiro Watanabe Dr. Kôichi Ohkubo Hideki Abe Dr. Tadashi Katoh Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(12):2826-2845
Potential immunosuppressive agents : Candelalides A, B and C (see figure), novel blockers of the voltage‐gated potassium channel Kv1.3, have been efficiently synthesized for the first time in a convergent and unified manner starting from (+)‐5‐methyl‐Wieland–Miescher ketone. The method explored has potential for preparing various types of candelalide analogues for the structure–activity relationship studies.
998.
Yoshihiro Kikkawa Kenji Kurokawa Mayuko Takahashi Hideki Abe 《Polymer Degradation and Stability》2010,95(8):1414-2483
Biodegradable block copolymer of poly(l-lactide-b-?-caprolactone) (P(LA-b-CL)) was dissolved in various solvents with different solubility as well as volatility, and spin-cast on a highly oriented pyrolytic graphite (HOPG) to prepare thin films. The surface morphologies were observed by using atomic force microscopy (AFM) in a dynamic force (tapping) mode. Particle like morphology was found in the thin films prepared form the dichloromethane and acetone. Higher volatility of dichloromethane and acetone resulted in the reflection of the particle like objects in the solution to HOPG substrate. In contrast, the P(LA-b-CL)s in toluene and 1,4-dioxane exhibited different morphologies compared to those in dichloromethane and acetone. Lower volatility of toluene and 1,4-dioxane assisted the epitaxial crystallization of PCL component along the HOPG lattice, that was revealed by enzymatic degradation of PLLA component by proteinase K. Thus, adjusting the solubility and solvent volatility for the film formation provided morphological divergence of the P(LA-b-CL) block copolymer, and this technique would be applicable for the surface patterning of biodegradable polymers. 相似文献
999.
Mohanty PS Kesavamoorthy R Matsumoto K Matsuoka H Venkatesan KA 《Langmuir : the ACS journal of surfaces and colloids》2006,22(10):4552-4557
Novel, monodisperse charged colloidal particles of polystyrene cross linked with divinylbenzene and surface-grafted with acrylic acid were synthesized by emulsion polymerization and were characterized by estimating the dissociable surface charge by conductivity titration, the particle effective charge by conductivity verses particle concentration, and the particle size by dynamic light scattering and atomic force microscopy. The structural ordering and dynamics were investigated as a function of the volume fraction of the particles using static and dynamic light scattering, respectively. Furthermore, from the electrophoresis measurements, these particles are found to have a high salt tolerance due to increases in charge as a function of salt concentration. 相似文献
1000.
The authors consider the finite volume approximation of a reaction-diffusion system with fast reversible reaction.It is deduced from a priori estimates that the approximate solution converges to the weak solution of the reaction-diffusion problem and satisfies estimates which do not depend on the kinetic rate.It follows that the solution converges to the solution of a nonlinear diffusion problem,as the size of the volume elements and the time steps converge to zero while the kinetic rate tends to infinity. 相似文献