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91.
DeBeer-Schmitt L Eskildsen MR Ichioka M Machida K Jenkins N Dewhurst CD Abrahamsen AB Bud'ko SL Canfield PC 《Physical review letters》2007,99(16):167001
The magnetic field distribution around the vortices in TmNi2B2C in the paramagnetic phase was studied experimentally as well as theoretically. The vortex form factor, measured by small-angle neutron scattering, is found to be field independent up to 0.6Hc2 followed by a sharp decrease at higher fields. The data are fitted well by solutions to the Eilenberger equations when paramagnetic effects due to the exchange interaction with the localized 4f Tm moments are included. The induced paramagnetic moments around the vortex cores act to maintain the field contrast probed by the form factor. 相似文献
92.
Amine‐Responsive Adaptable Nanospaces: Fluorescent Porous Coordination Polymer for Molecular Recognition 下载免费PDF全文
Ritesh Haldar Prof. Ryotaro Matsuda Prof. Susumu Kitagawa Prof. Subi J. George Prof. Tapas Kumar Maji 《Angewandte Chemie (International ed. in English)》2014,53(44):11772-11777
Flexible and dynamic porous coordination polymers (PCPs) with well‐defined nanospaces composed of chromophoric organic linkers provide a scaffold for encapsulation of versatile guest molecules through noncovalent interactions. PCPs thus provide a potential platform for molecular recognition. Herein, we report a flexible 3D supramolecular framework {[Zn(ndc)(o‐phen)]?DMF}n (o‐phen=1,10‐phenanthroline, ndc=2,6‐napthalenedicarboxylate) with confined nanospaces that can accommodate different electron‐donating aromatic amine guests with selective turn‐on emission signaling. This system serves as a molecular recognition platform through an emission‐readout process. Such unprecedented tunable emission with different amines is attributed to its emissive charge‐transfer (CT) complexation with o‐phen linkers. In certain cases this CT emission is further amplified by energy transfer from the chromophoric linker unit ndc, as evidenced by single‐crystal X‐ray structural characterization. 相似文献
93.
Selective Generation of Formamides through Photocatalytic CO2 Reduction Catalyzed by Ruthenium Carbonyl Compounds 下载免费PDF全文
Dr. Katsuaki Kobayashi Dr. Takashi Kikuchi Prof. Susumu Kitagawa Prof. Koji Tanaka 《Angewandte Chemie (International ed. in English)》2014,53(44):11813-11817
The selective formation of dialkyl formamides through photochemical CO2 reduction was developed as a means of utilizing CO2 as a C1 building block. Photochemical CO2 reduction catalyzed by a [Ru(bpy)2(CO)2]2+ (bpy: 2,2′‐bipyridyl)/[Ru(bpy)3]2+/Me2NH/Me2NH2+ system in CH3CN selectively produced dimethylformamide. In this process a ruthenium carbamoyl complex ([Ru(bpy)2(CO)(CONMe2)]+) formed by the nucleophilic attack of Me2NH on [Ru(bpy)2(CO)2]2+ worked as the precursor to DMF. Thus Me2NH acted as both the sacrificial electron donor and the substrate, while Me2NH2+ functioned as the proton source. Similar photochemical CO2 reductions using R2NH and R2NH2+ (R=Et, nPr, or nBu) also afforded the corresponding dialkyl formamides (R2NCHO) together with HCOOH as a by‐product. The main product from the CO2 reduction transitioned from R2NCHO to HCOOH with increases in the alkyl chain length of the R2NH. The selectivity between R2NCHO and HCOOH was found to depend on the rate of [Ru(bpy)2(CO)(CONR2)]+ formation. 相似文献
94.
Noriyuki Yoshii Yoshimichi Andoh Susumu Okazaki 《Journal of computational chemistry》2020,41(9):940-948
We derived a new expression for the electrostatic interaction of three-dimensional charge-neutral systems with two-dimensional periodic boundary conditions (slab geometry) using a fast multipole method (FMM). Contributions from all the image cells are expressed as a sum of real and reciprocal space terms, and a self-interaction term. The reciprocal space contribution consists of two parts: zero and nonzero terms of the absolute value of the reciprocal lattice vector. To test the new expressions, electrostatic interactions were calculated for a randomly placed charge distribution in a cubic box and liquid water produced by molecular dynamics calculation. The accuracy could be controlled by the degree of expansion of the FMM. In the present expression, the computational complexity of the electrostatic interaction of N-particle systems is order N, which is superior to that of the conventional two-dimensional periodic Ewald method for a slab geometry and the particle mesh Ewald method with a large empty space at an interface of the unit cell. © 2020 Wiley Periodicals, Inc. 相似文献
95.
Dr. Ming-Shui Yao Prof. Jia-Jia Zheng Ai-Qian Wu Prof. Gang Xu Sanjog S. Nagarkar Gen Zhang Masahiko Tsujimoto Prof. Shigeyoshi Sakaki Prof. Satoshi Horike Prof. Kenichi Otake Prof. Susumu Kitagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(1):178-182
Single-ligand-based electronically conductive porous coordination polymers/metal–organic frameworks (EC-PCPs/MOFs) fail to meet the requirements of numerous electronic applications owing to their limited tunability in terms of both conductivity and topology. In this study, a new 2D π-conjugated EC-MOF containing copper units with mixed trigonal ligands was developed: Cu3(HHTP)(THQ) (HHTP=2,3,6,7,10,11-hexahydrotriphenylene, THQ=tetrahydroxy-1,4-quinone). The modulated conductivity (σ≈2.53×10−5 S cm−1 with an activation energy of 0.30 eV) and high porosity (ca. 441.2 m2 g−1) of the Cu3(HHTP)(THQ) semiconductive nanowires provided an appropriate resistance baseline and highly accessible areas for the development of an excellent chemiresistive gas sensor. 相似文献
96.
Ming‐Shui Yao Jia‐Jia Zheng Ai‐Qian Wu Gang Xu Sanjog S. Nagarkar Gen Zhang Masahiko Tsujimoto Shigeyoshi Sakaki Satoshi Horike Kenichi Otake Susumu Kitagawa 《Angewandte Chemie (International ed. in English)》2020,59(1):172-176
Single‐ligand‐based electronically conductive porous coordination polymers/metal–organic frameworks (EC‐PCPs/MOFs) fail to meet the requirements of numerous electronic applications owing to their limited tunability in terms of both conductivity and topology. In this study, a new 2D π‐conjugated EC‐MOF containing copper units with mixed trigonal ligands was developed: Cu3(HHTP)(THQ) (HHTP=2,3,6,7,10,11‐hexahydrotriphenylene, THQ=tetrahydroxy‐1,4‐quinone). The modulated conductivity (σ≈2.53×10?5 S cm?1 with an activation energy of 0.30 eV) and high porosity (ca. 441.2 m2 g?1) of the Cu3(HHTP)(THQ) semiconductive nanowires provided an appropriate resistance baseline and highly accessible areas for the development of an excellent chemiresistive gas sensor. 相似文献
97.
Koji Yamamoto Kazuki Higuchi Masahiro Ogawa Hiromitsu Sogawa Shigeki Kuwata Yoshihiro Hayashi Susumu Kawauchi Toshikazu Takata 《化学:亚洲杂志》2020,15(3):356-359
We synthesised palladium and platinum complexes possessing cyclic and acyclic pincer‐type polyaromatic ligands and investigated their structural effect on the catalysis. The pincer‐type bis(6‐arylpyridin‐2‐yl)benzene skeleton was constructed via Kröhnke pyridine synthesis under transition metal‐free conditions on gram‐scale quantity. Ligand structure significantly influenced catalytic activity toward the platinum‐catalysed hydrosilylation of diphenyl acetylenes, despite the ligand‐independence of the conformations and electronic properties of these complexes. 相似文献
98.
Yukiko Kamiya Fuminori Sato Keiji Murayama Atsuji Kodama Susumu Uchiyama Hiroyuki Asanuma 《化学:亚洲杂志》2020,15(8):1266-1271
Serinol nucleic acid (SNA) is a promising candidate for nucleic acid‐based molecular probes and drugs due to its high affinity for RNA. Our previous work revealed that incorporation of 2,6‐diaminpurine (D), which can form three hydrogen bonds with uracil, into SNA increases the melting temperature of SNA‐RNA duplexes. However, D incorporation into short self‐complementary regions of SNA promoted self‐dimerization and hindered hybridization with RNA. Here we synthesized a SNA monomer of 2‐thiouracil (sU), which was expected to inhibit base pairing with D by steric hindrance between sulfur and the amino group. To prepare the SNA containing D and sU in high yield, we customized the protecting groups on D and sU monomers that can be readily deprotected under acidic conditions. Incorporation of D and sU into SNA facilitated stable duplex formation with target RNA by suppressing the self‐hybridization of SNA and increasing the stability of the heteroduplex of SNA and its complementary RNA. Our results have important implications for the development of SNA‐based probes and nucleic acid drugs. 相似文献
99.
Sato S Komoto T Kanamaru Y Kawamoto N Okada T Kaiho T Mogi K Morimoto S Umehara N Koda T Miyashita A Sakamoto T Niino Y Oka T 《Chemical & pharmaceutical bulletin》2002,50(2):292-297
New muq-opioid receptor (MOR) agonists containing 4-hydroxypiperidine, piperidine and piperazine moieties were synthesized and evaluated to find a peripheral opioid analgesic. Among the synthesized compounds, 12-[1-[3-(N,N-dimethylcarbamoyl)-3,3-diphenylpropyl]-4-hydroxypiperidin-4-yl]phenoxy]acetic acid (8: SS620) having phenoxyacetic acid and 4-hydroxypiperidine moieties showed the highest agonist potency on the MOR in an isolated guinea-pig ileum preparation, and it also had selectivity to the human MOR expressed in Chinese hamster ovary (CHO)-K1 cells compared with the same types of delta- and kappa-opioid receptors (DOR and KOR). In addition, compound 8 showed a 10 times more potent MOR agonist activity than loperamide. Furthermore, compound 8 showed a peripheral analgesic activity in vivo screening on rat. 相似文献
100.
For the purpose of evaluating optimal fill level of starting materials in a high-shear mixer, discrete element method (DEM) simulation was conducted to visualize kinetic status between particles. The simulation results obtained by changing fill levels were used to determine solid fraction of particles, particle velocity, particle velocity vector, and kinetic energy and discuss the flow pattern. Optimal fill level was obtained from the information on these matters. It was pointed out that understanding the kinetic energy between particles in an agitating vessel was effective in determining the optimal fill level. Granulation experiment was conducted to validate the optimal fill level obtained by the simulation, confirming the good agreement between these two results. It was pointed out that determination of kinetic energy between particles through the simulation was effective in obtaining an index of the kinetic status of particles. Further, it was confirmed that the simulation could provide more information than conventional granulation experiments could provide and also helpful in optimizing the operating conditions. 相似文献