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2.
Ferroelectric Coordination Polymers Self‐Assembled from Mesogenic Zinc(II) Porphyrin and Dipolar Bridging Ligands 下载免费PDF全文
Dr. Joseph K.‐H. Hui Hiroyuki Kishida Keita Ishiba Kenta Takemasu Dr. Masa‐aki Morikawa Prof. Dr. Nobuo Kimizuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14213-14218
A new class of ferroelectric coordination‐based polymers has been developed by the self‐assembly of lipophilic zinc porphyrin ( ZnP ) and ditopic bridging ligands. The ligands contain dipolar benzothiadiazole or fluorobenzene units, which are axially coordinated to ZnP with the dipole moments oriented perpendicular to the coordination axes. The coordination‐based polymers show ferroelectric characteristics in the liquid crystalline state, as revealed by distinctive hysteresis in the polarization–electric field (P–E) loops and inversion current peaks in current–voltage (I–V) loops. The observed ferroelectric properties are explainable by flip–flop rotation of the dipolar axle ligands induced by the applied electric field, as demonstrated by the positive‐up–negative‐down (PUND) measurements. The present system provides a new operating principle in supramolecular ferroelectrics. 相似文献
3.
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Noriaki Nishiguchi Takafumi Kinuta Yoko Nakano Dr. Takunori Harada Dr. Nobuo Tajima Tomohiro Sato Prof. Dr. Michiya Fujiki Prof. Dr. Reiko Kuroda Prof. Dr. Yoshio Matsubara Dr. Yoshitane Imai 《化学:亚洲杂志》2011,6(4):1092-1098
The solid‐state chiral optical properties of a 4‐(2‐arylethynyl)‐benzoic acid/amine supramolecular organic fluorophore can be controlled by changing the arylethynyl group of the achiral 4‐(2‐arylethynyl)‐benzoic acid component molecule rather than the chirality of the amine component molecule. 相似文献
5.
We study the survival probability and the growth rate for branching random walks in random environment (BRWRE). The particles
perform simple symmetric random walks on the d-dimensional integer lattice, while at each time unit, they split into independent copies according to time–space i.i.d. offspring
distributions. The BRWRE is naturally associated with the directed polymers in random environment (DPRE), for which the quantity
called the free energy is well studied. We discuss the survival probability (both global and local) for BRWRE and give a criterion
for its positivity in terms of the free energy of the associated DPRE. We also show that the global growth rate for the number
of particles in BRWRE is given by the free energy of the associated DPRE, though the local growth rate is given by the directional
free energy. 相似文献
6.
Ryoma Masuda Yuuya Kawasaki Kazunobu Igawa Yoshiyuki Manabe Hiroshi Fujii Nobuo Kato Katsuhiko Tomooka Junko Ohkanda 《化学:亚洲杂志》2020,15(6):742-747
Mid‐sized molecules have emerged as an attractive chemical space and potentially provide a robust basis for the development of synthetic agents to control intracellular protein interactions. However, the limited cell permeability and chemical tractability of such agents remain to be addressed. We envisioned that target‐templated synthesis of such mid‐sized molecules might provide a solution. Here, we exploited a copper‐free Huisgen cycloaddition for template synthesis using a peptide fragment containing a 4,8‐diazacyclononyne (DACN) moiety and an azide‐containing fusicoccin derivative in the presence or absence of recombinant 14‐3‐3ζ protein in vitro. Time‐course changes in the yield of products demonstrated that the reaction was accelerated in the presence of 14‐3‐3 and one of the regioisomers was generated predominantly, supporting the template effect. 相似文献
7.
B. Shinozaki S. Takada N. Kokubo K. Makise K. Mitsuishi K. Yamada K. Yano H. Nakamura 《Physica C: Superconductivity and its Applications》2011,471(21-22):717-720
In order to investigate the relation among the superconducting transition Tc, carrier density n, resistivity ρ and the microstructure in the polycrystalline (In2O3)1?x–(ZnO)x films, we prepared specimen films by post annealing of amorphous films with x = 0.025 at various annealing temperature Ta and for annealing time ta = 1 h and 4 h. As for microstructures, we have investigated the distribution of elements by scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). We have found followings: (1) The annealed films clearly show the superconductivity of which Tc depends on Ta, ta and n. This indicates that the superconductivity is determined by the combination of crystallinity and carrier density. (2) The data on STEM–EELS spectra mapping of indium plasmon indicate that droplets of the pure indium phase exist inside a film, where the distribution of these droplets dispersed. Therefore, it seems that droplets do not form an electrical conducting path, that is, it is possible that observed superconductivity is due to intrinsic characteristic of polycrystalline (In2O3)1?x–(ZnO)x films. 相似文献
8.
Wasura Soonthorntantikul Natchanun Leepipatpiboon Tohru Ikegami Nobuo Tanaka Thumnoon Nhujak 《Journal of chromatography. A》2009,1216(31):5868-5874
Stationary phase selectivities for halogenated compounds in reversed-phase HPLC were compared using C18 monolithic silica capillary columns modified with poly(octadecyl methacrylate) (ODM) and octadecyl moieties (ODS). The preferential retention of halogenated benzenes on ODM was observed in methanol/water and acetonitrile/water mobile phases. In selectivity comparison of selected analytes on ODM and ODS, greater selectivities for halogenated compounds were obtained with respect to alkylbenzenes on an ODM column, while similar selectivities were observed with a homologous series of alkylbenzenes on ODM and ODS columns. These data can be explained by greater dispersive interactions by more densely packed octadecyl groups on the ODM polymer coated column together with the contribution of carbonyl groups in ODM side chains. For the positional isomeric separation of dihalogenated benzenes (ortho-, meta-, para-), the ODM column also provided better separation of these isomers for the adjacently eluted isomers that cannot be completely separated on an ODS column in the same mobile phase. These results imply that the ODM column can be used as a better alternative to the ODS column for the separation of other halogenated compounds. 相似文献
9.
The molecular aggregation of oxazine 1 (Ox1) and oxazine 4 (Ox4) in reduced charge montmorillonite (RCM) colloids was investigated
by absorption and fluorescence spectroscopies. The aggregation was significantly influenced by the structure of dye cations.
Presence of four hydrophobic ethyl groups attached to the ammonium substituents in Ox1 cation prevented formation of closely
packed sandwich-type assemblies (H-aggregates). Significant effect of the layer charge was observed for Ox4/RCMs dispersions. Large amounts of the Ox4 H-aggregates were formed in the systems with RCMs of the highest layer charge and reflected in quenched fluorescence. The presence
of J-aggregates was proven by absorption spectra for the systems with Ox4 and low-charge RCMs. The flocculation of the lowest
charge RCM colloids led to an extensive reduction of the luminescence. The trends and effects of the dye molecular structure
and RCM properties are compared with the results previously published for other types of dyes. 相似文献
10.
The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than in the conventional organic solvent.Furthermore,in the Diels-AIder reactions of 2- and 2,5-alkylfurans with N-alkylmaleimide,the reactivity increases by extending the alkyl chain length of N-alkylmaleimide.In addition,it was demonstrated that endo-selectivity increases when 2,5-disubstituted furans are used.These results will be explained by comparing the stability of the Diels-Alder adduct with that of the products obtained from the reactions of 2-substituted furans and 2,5-disubstituted furans. 相似文献