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131.
Nobuaki Takahashi Takehisa Yoshinari Shin-ichiro Nagasaka Aishi Yamamoto Takenari Goto 《Journal of solid state chemistry》2004,177(10):3479-3483
Highly purified single crystals of pyrene were made by a gas phase crystal growth method from 180 times of zone-refined pyrene. The absorption spectra of the single crystal have been transformed from the reflection spectra between 2.5 and at 2, and room temperature. The dry powder of β-cyclodextrin including pyrene single molecule were prepared in vacuum to investigate the electronic states of the isolated molecule. The absorption spectra of the single molecule show similar spectra to those of the single crystal. The pyrene molecule keeps its electronic character even in the single crystal. 相似文献
132.
Yuki Shirakawa Dr. Kiyonori Takahashi Dr. Hiroyasu Sato Dr. Norihisa Hoshino Hayato Anetai Prof. Shin-ichiro Noro Prof. Tomoyuki Akutagawa Prof. Takayoshi Nakamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(28):6920-6927
The pseudo-polyrotaxane structure of [(H-bpy+)- (DB-24-crown-8)]∞ (H-bpy+ = monoprotonated 4,4-bipyridinium; DB-24-crown-8 = dibenzo-24-crown-8) has been incorporated into the anion radical salt [Ni(dmit)2]− (dmit2− = 1,3-dithiole-2-thione-4,5-dithiolate). (H-bpy+)(DB-24-crown-8)[Ni(dmit)2]− crystallized as two polymorphs, crystals 1 and 2 . Crystal 1 was found to have a lower density and looser packing structure in which H-bpy+ forms a one-dimensional hydrogen-bonding chain that passes though the crown ether ring of DB-24-crown-8. DB-24-crown-8 adopts a U-shaped conformation in which two phenylene rings sandwich one of the pyridyl rings of H-bpy+ to stabilize the structure. The [Ni(dmit)2]− anions are arranged in a layer parallel to the (10) plane with uniform side-by-side interactions. A structural phase transition was observed at 235 K, accompanied by ordering of the polyrotaxane structure. In crystal 1 , at 173 K, H-bpy+ is twisted around the central C−C bond, which perturbs the arrangement of [Ni(dmit)2]− through short C−H⋅⋅⋅S contacts. As a result, the semiconducting behavior, with an activation energy of 0.21 eV, becomes insulating below 235 K. The crystal exhibits ferromagnetic interactions because of the weak side-by-side interactions between [Ni(dmit)2]− anions. Crystal 2 has a similar pseudo-polyrotaxane structure but showed no phase transition. This suggests that the looser crystal packing in crystal 1 induces the structural change of the pseudo-polyrotaxane, perturbing the electron system of [Ni(dmit)2]−. 相似文献
133.
134.
Shin-ichiro Fujii Kazumi InagakiAkiko Takatsu Takashi YaritaKoichi Chiba 《Journal of chromatography. A》2009,1216(44):7488-7492
We performed the quantification of phosphorus in deoxynucleotides using capillary electrophoresis (CE) and micro-HPLC (μHPLC) hyphenated with inductively coupled plasma mass spectrometry (ICP-MS). DNA and its component units have conventionally been determined by photometry; however, more selective and sensitive methods are needed for small biological samples. CE and μHPLC offer the advantages of good separation and small consumption of samples, and ICP-MS is a highly sensitive technique for the determination of a chemical element. Therefore, we have developed an interface device for combining CE and μHPLC with ICP-MS for quantifying nucleotides based on phosphorus content. The interface utilizes 4.5 μL/min for nebulizing and effective introduction of the sample into ICP. The samples of nucleotides and free phosphoric acid were well separated in the CE–ICP-MS measurement, and the calibration curves (1–100 μg/mL) of the nucleotides showed a linear (R2 > 0.999) increase in intensity. Similarly, the samples of nucleotides were baseline separated using μHPLC–ICP-MS, and the calibration curves of the nucleotides were linear (R2 > 0.998). The detection limits of these species and phosphorus in nucleotides using CE–ICP-MS and μHPLC–ICP-MS were 0.77–6.5 ng/mL and 4.0–6.5 ng/mL, respectively. These values were about one or two orders lower than those in a previous report. The sample volumes of these experiments were calculated to be about 10 nL and 50 nL per analysis. Therefore, these analytical methods have the potential to be useful for the determination of biological samples, such as DNA and RNA molecules. 相似文献
135.
Haitao Zheng Jingli Zhou Jimei Zhang Rong Huang Hailian Jia Shin-ichiro Suye 《Mikrochimica acta》2009,165(1-2):109-115
A ferrocene-labeled high molecular weight cofactor derivative (PEI-Fc-NAD) was prepared by attaching both ferrocene and nicotinamide adenine dinucleotide (NAD+) to a water soluble polyelectrolyte, polyethylenimine (PEI). Approximately 9.8% and 2.9% of all the primary amino groups of PEI were coupled with ferrocene and the bioactive cofactor, respectively. The cyclic voltammograms of PEI-Fc-NAD exhibited a one-electron transfer process, and the difference between the anodic and cathodic peak potential was found to be 80 mV. The PEI-Fc-NAD was used together with NAD-dependent dehydrogenase to construct a reagentless biosensor. An NAD-dependent alcohol dehydrogenase (ADH) was selected as the model enzyme, and both ADH and PEI-Fc-NAD were retained onto the sensing area of gold electrodes by a dialysis membrane or immobilized by layer-by-layer adsorption method. In both cases, the modified electrodes showed current response to ethanol without the addition of native NAD+ to the system, which suggested that the electrical communication between ADH and the electrode was achieved through PEI-Fc-NAD. In summary, PEI-Fc-NAD provides a new way for immobilization of mediator and cofactor, and exhibits the potential as a platform for constructing reagentless NAD-dependent dehydrogenase biosensors. 相似文献
136.
Dr. Masaru Fujibayashi Yu Watari Dr. Ryo Tsunashima Prof. Sadafumi Nishihara Prof. Shin-ichiro Noro Dr. Chang-Gen Lin Prof. Yu-Fei Song Dr. Kiyonori Takahashi Prof. Takayoshi Nakamura Prof. Tomoyuki Akutagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22632-22636
The structural phase of a metal oxide changes with temperature and pressure. During phase transitions, component ions move in multidimensional metal–oxygen networks. Such macroscopic structural events are robust to changes in particle size, even at scales of around 10 nm, and size effects limiting these transitions are particularly important in, for example, high-density memory applications of ferroelectrics. In this study, we examined structural transitions of the molecular metal oxide [Na@(SO3)2(n-BuPO3)4MoV4MoVI14O49]5− (Molecule 1 ) at approximately 2 nm by using single-crystal X-ray diffraction analysis. The Na+ encapsulated in the discrete metal-oxide anion exhibited a reversible order–disorder transition with distortion of the Mo–O molecular framework induced by temperature. Similar order–disorder transitions were also triggered by chemical pressure induced by removing crystalline solvent molecules in the single-crystal state or by substituting the countercation to change the molecular packing. 相似文献
137.
Gefei Li Masato Noguchi Kensuke Nakamura Ryohei Hayasaka Yuuki Tanaka Shin-ichiro Shoda 《Tetrahedron letters》2018,59(37):3428-3431
A practical two-step synthetic process for 1-deoxy sugars has been established. The process consists of the direct introduction of a dimethyldithiocarbamate group into the anomeric center of unprotected sugars and subsequent hydrogenation in the AIBN-H3PO2-NaHCO3 system. No protecting groups are needed to synthesize 1-deoxy monosaccharides and 1-deoxy disaccharides. 相似文献
138.
Kenshu Fujiwara Saori Yoshimoto Ayumi Takizawa Shin-ichiro Souma Hirofumi Mishima Akio Murai Hidetoshi Kawai Takanori Suzuki 《Tetrahedron letters》2005,46(40):6819-6822
Laurencin was efficiently synthesized from a C-glycoside derivative based on ring expansion of the oxane part of the starting compound into an eight-membered cyclic ether via a ring-cleavage/ring-closing olefin metathesis process, stereoselective introduction of a bromo group at C4, and convergent construction of the side-chain part using a lithiated enyne unit. 相似文献
139.
Chuen-Huei Yang Itoh K. Shin-ichiro Takahashi Obara M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1993,21(6):731-738
A measurement is made of the spectroscopic characteristics of argon plasma produced by multistage pseudospark discharges in a peculiar geometry which has not yet been reported in literature. High electron temperature, high peak current density, and a high degree of ionization are demonstrated in such a device. The population number density of the upper and lower levels of 488.0, 476.6, 514.5, 351.1, and 363.8 nm transitions in ArII and ArIII are measured. The ultraviolet emission characteristics of pure Ar and Ar/He mixture plasmas are compared. An appreciable increase is observed in peak intensities of ArIII lines when nitrogen is added to Ar 相似文献
140.