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41.
42.
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
43.
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
44.
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
45.
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
46.
47.
Kawahara M Kabir MK Yamada K Adachi K Kumagai H Narumi Y Kindo K Kitagawa S Kawata S 《Inorganic chemistry》2004,43(1):92-100
Two new copper(II) compounds of chloranilate and 2,2':6',2' '-terpyridine have been synthesized, and the structures have been solved by the single-crystal X-ray diffraction method. The crystal structure of [[Cu(2)(CA)(terpy)(2)][Cu(CA)(2)]](n)(1), where H(2)CA = chloranilic acid and terpy = 2,2':6',2' '-terpyridine, consists of two modules, the dimer unit [Cu(2)(CA)(terpy)(2)](2+) and the anionic mononuclear unit [Cu(CA)(2)](2)(-), forming an alternated chain. The chain is stabilized by semicoordinating and additional but efficient secondary bonding interactions. The crystal structure of [[Cu(2)(CA)(terpy)(2)(dmso)(2)][Cu(CA)(2)(dmso)(2)](EtOH)](n)(2), where dmso = dimethyl sulfoxide, consists of solvent molecules and two discrete modules, the dimer unit [Cu(2)(CA)(terpy)(2)(dmso)(2)](2+) and the anionic mononuclear unit [Cu(CA)(2)(dmso)(2)](2)(-). The dimer units form a layer by secondary bonding interactions, and the monomer units and ethanol molecules are introduced between the layers. The magnetic properties of 1 and 2 have been investigated in the temperature range 2.0-300 K. A weak ferromagnetic interaction was observed in 1, J(a) = 2.36 cm(-)(1) and zJ(b) = -0.68 cm(-)(1) while no exchange coupling was observed in 2. 相似文献
48.
Czesław Rudowicz Ireneusz Stefaniuk Roman Dziembaj Hitoshi Ohta Marcin Molenda Susumu Okubo Makoto Yoshida 《Research on Chemical Intermediates》2007,33(8):853-862
This paper deals with the analysis of the temperature dependence of high-frequency EMR (HF-EMR) spectra due to Mn3+ and Mn4+ ions in the lithium manganese spinel LiMn2O4. A range of powder samples obtained by the sol-gel method with calcinations in several temperature ranges were prepared for
this study. Based on the initial characterization carried out by a number of techniques, the physicochemical and structural
properties of the samples were earlier determined. Independently, temperature magnetization and HF-EMR measurements were carried
out. The EMR spectra vary strongly between samples, indicating possible structural or chemical changes. Quantitative analysis
of the temperature dependence of the HF-EMR spectra due to Mn3+ and Mn4+ ions in LiMn2O4 is presented in this paper. The spectral analysis concerns the line shape, linewidth, intensity and g-factors. Fittings using the Lorentzian spectral shape and, to a certain extent, the Gaussian spectral shape have been carried
out in order to parameterize the temperature dependence of the HF-EMR spectra. This parameterization of the HF-EMR experimental
data enables a deeper characterization of the samples. Subsequently, a better insight into the role of the Mn3+ and Mn4+ ions in accounting for the characteristics most suitable for application of LiMn2O4 as a cathode material may be gained. 相似文献
49.
Susumu Tajima Yukiyoshi Nagai Osamu Sekiguchi Masao Fujishige Nozomu Uchida 《Journal of the American Society for Mass Spectrometry》1995,6(3):202-206
The spontaneous unimolecular dissociation reaction of methyl lactate (1) ionized by electron impact was investigated by a combination of mass-analyzed ion kinetic energy spectrometry and deuterium labeling. The metastable ions 1+· decompose in a variety of ways: four fragment peaks are observed at m/z 89, 76, 61, and 45, which correspond to the losses of ?H3, CO, CH3?O, and ?OOCH3, respectively. Double hydrogen atom transfer occurs in the third reaction. The source-generated m/z 61 ions decompose into oxygen-protonated methanols at m/z 33 ([CH3OH 2 + ]) by the loss of CO with double hydrogen atom migration. Both hydroxyl and methyne hydrogen atoms in 1 +· are present in the resultant protonated methanols. 相似文献
50.