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61.
Toshio Shimizu Kazuko Iwata Hideyuki Murakami Nobumasa Kamigata 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):457-458
Sulfur-containing cycloalkenes possessing disulfide units 1, 2, and 3 were obtained by oxidation of cis-disodium ethene-1,2-dithiolate, and their crystal structures were determined by the X-ray crystallographic analyses. Compound 1 was found to give the ring expansion product 3 in acetonitrile even at room temperature and also form reactive thioaldehyde under irradiation. 相似文献
62.
Kiyoshi Tanaka Yasuhiro Yamamoto Hiroto Obara Satoru Iwata 《Supramolecular chemistry》2013,25(4):347-352
5,15- cis -bis(Ureidophenyl)porphyrins have significant recognizing ability for p -benzoquinones through four-point hydrogen bonding. Although an unusual temperature-dependence of the complexation is observed with bis( N '-phenylureidophenyl) porphyrin, bis( N '-ethylureidophenyl)porphyrin shows a satisfactorily linear van't Hoff plot and recognizes an electron-rich p -benzoquinone such as tetramethyl- p -benzoquinone more effectively, which is ascribed to the large enthalpy change in the complex. 相似文献
63.
Yin Li Zsolt Csók László Kollár Koichi Iwata Erzsébet Szász 《Supramolecular chemistry》2013,25(6):374-378
2-Methylresorcinarene and its methylene-bridged cavitand derivative as host compounds were investigated in selective complexation of alkali metal ions as guests in methanol media by photoluminescence measurements. These host molecules possess either flexible (2-methylresorcinarene) or rigid (cavitand) molecular skeleton. The Benesi–Hildebrand method and the van't Hoff theory have been applied to determine the stability constants and the thermodynamic parameters, respectively. Considerable interactions between 2-methylresorcinarene and Li+ or Na+ ions have been observed while the rigid cavitand derivative can interact only with K+ or Cs+ ions. Neither the complexes of 2-methylresorcinarene with K+ or Cs+ nor those of the cavitand derivative with Li+ or Na+ ions are stable at room temperature in methanol media. Quantum-chemical investigations justified that only solvated Li+ and Na+ ions can form stable complexes with 2-methylresorcinarene while unsolvated K+ and Cs+ ions form stable complexes with the methylene-bridged cavitand. These results highlight that the stability of the guest solvation shell and its size could play a key role in the selectivity behaviour of host molecules. 相似文献
64.
Harry Adams Neil A. Bailey David E. Fenton Choki Fukuhara Masatoshi Kanesato 《Supramolecular chemistry》2013,25(4):325-330
Abstract The synthesis and crystal structure of the diprotonated cryptand derived from the reaction of tren and 2,6-diacetyl pyridine is reported. The imino nitrogens of the Schiff base linkages are directed so that the dicarbimine functions are in trans, trans geometry relative to the pyridine C-N bond. This configuration has not previously been reported in related pyridine-derived Schiff base macrocycles. 相似文献
65.
Kenichiro Todoroki Hiroki Hashimoto Kazuyuki Machida Miki Itoyama Tadashi Hayama Hideyuki Yoshida Hitoshi Nohta Manabu Nakashima Masatoshi Yamaguchi 《Journal of separation science》2013,36(2):232-238
In this study, we combined a column‐switching system with a fluorous scavenging derivatization method to develop a fully automated reagent peak‐free LC fluorescence detection protocol for the analysis of highly polar carboxylic acids. In this method, highly polar carboxylic acids were derivatized with fluorescent 1‐pyrenemethylamine in the presence of 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide and 1‐hydroxy‐1H‐benzotriazole. Residual excess of the unreacted reagent was tagged with 2‐(perfluorooctyl)ethyl isocyanate and then removed selectively using a fluorous column‐switching system placed in front of an analytical reversed‐phase column. The signal of the fluorous‐tagged unreacted reagent was completely absent in the resulting chromatograms; therefore, it did not interfere with the quantification of each acid especially those eluted before 20 min. The detection limits (S/N = 3) for the examined acids were in the range from 4.0 to 22 fmol per injection. We have applied this method to comparative analysis of highly polar carboxylic acids in urine samples obtained from diabetes mellitus type‐II model mice and their control. 相似文献
66.
Yuki Yanagisawa Takeshi Kageyama Naohisa Wada Masatoshi Tanaka Shin‐ya Ohno 《Photochemistry and photobiology》2013,89(6):1490-1496
The time‐dependent characteristics of firefly bioluminescence initiated by manual injection of adenosine triphosphate (ATP) into buffer solution containing luciferin (Ln), luciferase (Luc) and Mg2+ were measured with a resolution of 10 ms, and compared with those obtained by photolysis of caged ATP. The time course depends on pH; both rise and decay rates decrease when pH is lowered from 7.8 to 6.8. In contrast, the parameter λ in the kinetic formula related to diffusion of ATP is almost independent of pH. The pH dependence of the time course of bioluminescence can be explained by the same pH tendency as the rate of ATP binding at the active site of Luc. The time‐resolved spectra can be decomposed into two Gaussian components with maxima at 2.2 and 2.0 eV. At pH 7.8, the band at 2.2 eV is more intense than that at 2.0 eV for all three concentration conditions. At lower pH, the band at 2.2 eV becomes weaker than that at 2.0 eV. The intensity ratio of the 2.0 and 2.2 eV bands is constant for duration time of 600 s for both injection and photolysis experiments, and the above conclusions are unaffected by the concentration ratio [Ln]/[Luc]. 相似文献
67.
Naoya Hosoda Hideaki Kamito Miki Takano Yoshitaka Takebe Yoshitaka Yamaguchi Masatoshi Asami 《Tetrahedron》2013,69(6):1739-1746
Chiral diamines, 2-(anilinophenylmethyl)pyrrolidines and 2-(anilinodiphenylmethyl)pyrrolidine, were prepared from N-(tert-butoxycarbonyl)pyrrolidine or (S)-proline as a starting material, respectively. These chiral diamines were efficient for the catalytic enantioselective borane reduction of acetophenone. Using (S)-2-(anilinodiphenylmethyl)pyrrolidine, chiral secondary alcohols were obtained from prochiral ketones with good to excellent enantiomeric excesses (up to 98% ee). 相似文献
68.
Application of 28Mg for characterization of Mg uptake in rice seedling under different pH conditions
N. I. Kobayashi N. Iwata T. Saito H. Suzuki R. Iwata K. Tanoi T. M. Nakanishi 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):531-534
The magnesium (Mg) uptake of rice seedlings treated with different pH solutions was investigated using tracer of 28Mg. The application of 28Mg enabled the determination of Mg uptake amount within 15 min of the different pH treatments. The uptake amount of 28Mg and its distribution in rice plants were determined by using the imaging plate. The result demonstrated that the Mg uptake amount was approximately 3 μmol/15 min per plant in 0.27 mM Mg solution at pH 5.6, and this uptake decreased by 30 % at lower pH conditions (pH 4.5). On the contrary, the pH 6.5 condition induced the Mg uptake activity to 4.4 μmol/15 min. The inverse relationship found between proton concentration in nutrient solution and the Mg uptake amount within 15 min of treatment demonstrated that the low pH condition could inhibit the Mg uptake activity as a consequence of the competition between Mg2+ and proton. It is concluded that under low pH conditions, regardless of other factors, there is a decrease of Mg uptake activity in rice roots. 相似文献
69.
Wangdong Zeng Dr. Masatoshi Ishida Sangsu Lee Young Mo Sung Dr. Zebing Zeng Yong Ni Prof. Chunyan Chi Prof. Dongho Kim Prof. Jishan Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(49):16814-16824
A p‐quinodimethane (p‐QDM)‐bridged porphyrin dimer 1 has been prepared for the first time. An unexpected Michael addition reaction took place when we attempted to synthesize compound 1 by reaction of the cross‐conjugated keto‐linked porphyrin dimers 8 a and 8 b with alkynyl/aryl Grignard reagents. Alternatively, compound 1 could be successfully prepared by intramolecular Friedel–Crafts alkylation of the diol‐linked porphyrin dimer 14 with concomitant oxidation in air. Compound 1 shows intense one‐photon absorption (OPA, λmax=955 nm, ε=45400 M ?1 cm?1) and a large two‐photon absorption (TPA) cross‐section (σ(2)max=2080 GM at 1800 nm) in the near‐infrared (NIR) region due to its extended π‐conjugation and quinoidal character. It also exhibits a short singlet excited‐state lifetime of 25 ps. The cyclic voltammogram of 1 displays multiple redox waves with a small electrochemical energy gap of 0.86 eV. The ground‐state geometry, electronic structure, and optical properties of 1 have been further studied by density functional theory (DFT) calculations and compared with those of the keto‐linked dimer 8 b . This research has revealed that incorporation of a p‐QDM unit into the porphyrin framework had a significant impact on its optical and electronic properties, leading to a novel NIR OPA and TPA chromophore. 相似文献
70.
Prof. Dr. Yoshihiko Yamamoto Shota Mori Dr. Masatoshi Shibuya 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):12034-12041
The transfer‐hydrogenative cyclization of 1,6‐diynes with Hantzsch 1,4‐dihydropyridine as a H2 surrogate was performed in the presence of a cationic ruthenium catalyst of the type [Cp′Ru(MeCN)3PF6]. Exocyclic 1,3‐dienes or their 1,4‐hydrogenation products, cycloalkenes, were selectively obtained, depending on the substrate structure and the reaction conditions. 相似文献