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111.
Manabu Yamada Muniyappan Rajiv Gandhi Yoshihiko Kondo Fumio Hamada 《Supramolecular chemistry》2014,26(7-8):620-630
The ability of chloroform solutions of p-diethylaminomethylthiacalix[4]arene 1 to extract platinum from HCl media was tested. As an ion-pair extractant, compound 1 had the highest platinum extraction ability among all the thiacalix[n]arene derivatives tested in this study. Compound 1 was a highly specific extractant for Pt(IV) ions from single-metal solutions and platinum-group metal solutions from automotive catalyst residue. Various conditions such as contact time, pH, concentration of 1, effect of chloride ions, effect of acidity and Pt(IV) concentration were studied. The distribution ratio of platinum ions (D) was calculated. The platinum complex stoichiometry ratio was obtained using slope analysis. The 1–Pt(IV) complex was characterised using X-ray photoelectron spectroscopy, FT-IR and 1H NMR. Finally, the Pt(IV) extraction percentage of compound 1 was compared with that of previously reported thiacalix[n]arene-based extractants. 相似文献
112.
Dr. Masaki Yoshida Dr. Mio Kondo Prof. Toshikazu Nakamura Prof. Ken Sakai Prof. Shigeyuki Masaoka 《Angewandte Chemie (International ed. in English)》2014,53(43):11519-11523
A series of [{(terpy)(bpy)Ru}(μ‐O){Ru(bpy)(terpy)}]n+ ( [RuORu]n+ , terpy=2,2′;6′,2′′‐terpyridine, bpy=2,2′‐bipyridine) was systematically synthesized and characterized in three distinct redox states (n=3, 4, and 5 for RuII,III2 , RuIII,III2 , and RuIII,IV2 , respectively). The crystal structures of [RuORu]n+ (n=3, 4, 5) in all three redox states were successfully determined. X‐ray crystallography showed that the Ru? O distances and the Ru‐O‐Ru angles are mainly regulated by the oxidation states of the ruthenium centers. X‐ray crystallography and ESR spectra clearly revealed the detailed electronic structures of two mixed‐valence complexes, [RuIIIORuIV]5+ and [RuIIORuIII]3+ , in which each unpaired electron is completely delocalized across the oxo‐bridged dinuclear core. These findings allow us to understand the systematic changes in structure and electronic state that accompany the changes in the redox state. 相似文献
113.
Jie Zhu Dr. Ryota Osuga Prof. Ryo Ishikawa Prof. Naoya Shibata Prof. Yuichi Ikuhara Prof. Junko N. Kondo Prof. Masaru Ogura Prof. Jihong Yu Prof. Toru Wakihara Prof. Zhendong Liu Prof. Tatsuya Okubo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(44):19837-19842
Encapsulating metal nanoclusters into zeolites combines the superior catalytic activity of the nanoclusters with high stability and unique shape selectivity of the crystalline microporous materials. The preparation of such bifunctional catalysts, however, is often restricted by the mismatching in time scale between the fast formation of nanoclusters and the slow crystallization of zeolites. We herein demonstrate a novel strategy to overcome the mismatching issue, in which the crystallization of zeolites is expedited so as to synchronize it with the rapid formation of nanoclusters. The concept was demonstrated by confining Pt and Sn nanoclusters into a ZSM-5 (MFI) zeolite in the course of its crystallization, leading to an ultrafast, in situ encapsulation within just 5 min. The Pt/Sn-ZSM-5 exhibited exceptional activity and selectivity with stability in the dehydrogenation of propane to propene. This method of ultrafast encapsulation opens up a new avenue for designing and synthesizing composite zeolitic materials with structural and compositional complexity. 相似文献
114.
Masaki Kondo Junichiro Kanazawa Tomohiro Ichikawa Takumi Shimokawa Yuki Nagashima Kazunori Miyamoto Masanobu Uchiyama 《Angewandte Chemie (International ed. in English)》2020,59(5):1970-1974
The silaboration of [1.1.1]propellane enables direct introduction of B and Si functional groups onto the bicyclo[1.1.1]pentane (BCP) scaffold in high yield under mild, additive‐free conditions. The silaborated BCP can be obtained on a gram‐scale in a single step without the need for column‐chromatographic purification, and is storable and easy to handle, providing a versatile synthetic intermediate for BCP derivatives. We also describe various conversions of the C?B/C?Si bonds on the BCP scaffold, including development of a modified Suzuki–Miyaura cross‐coupling reaction at the highly sterically hindered bridgehead sp3 carbon center of the BCP skeleton using a combination of highly activated BCP boronic esters, copper(I) oxide, and a PdCl2(dppf) catalyst system. 相似文献
115.
116.
K. Kondo H. Kawabata S. Ueda H. Hasegawa J. Inaba O. Mitamura Y. Seike Y. Ohmomo 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(2):305-312
We investigated the distribution of aquatic plants and the absorption of radionuclides by them in the brackish Lake Obuchi, Japan, which is bordered by nuclear fuel cycle facilities. We studied 5 species of submerged plants: Zannichellia palustris, Ruppia maritima, Potamogeton pectinatus, Zostera japonica, and Z. marina. The plants contained many elements, including radionuclides. The concentrations of 238U, 137Cs, and 90Sr in Z. marina were 11.3-12.4, 0.000-0.144, and 0.151-0.202 Bq.kg-1 dw, respectively. Those in Z. japonica were 5.2-8.8, 0.000-0.267, and 0.081-0.175 Bq.kg-1 dw, respectively. The concentrations of these radionuclides in the plants tended to be higher in higher-salinity regions than in lower-salinity regions of the lake. We found a close relationship between photosynthetic activity and the absorption of stable Sr by plants in the laboratory. Salinity, illumination, and water temperature influenced the photosynthetic activity of the plants and the consequent absorption of elements. 相似文献
117.
118.
Solubility Switching of Metallophthalocyanines and Their Larger Derivatives upon Encapsulation
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Dr. Kei Kondo Prof. Dr. Munetaka Akita Dr. Michito Yoshizawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1937-1940
Metallophthalocyanines (MPcs) are very useful pigments but scarcely soluble without appropriate functional groups in common solvents. Herein, we report that bent polyaromatic amphiphiles act as excellent solubilizing reagents for nonfunctionalized MPcs and larger MPc derivatives (e.g., CuPc, perhalogenated CuPcs, Cu‐naphthalocyanine, CuPc polymers, and double‐decker MPcs) in neutral water upon encapsulation. The resultant MPc nanocomposites display high stability towards heat and pH change. More importantly, the encapsulated MPcs can be released by simple protocols under mild conditions both into a bulk solvent and onto glass or polymer plates. 相似文献
119.
120.
Fourier transform spectra recorded using (a) natural abundance water vapor, (b) H218O-enriched water vapor, and (c) H217O-enriched water vapor are analyzed. The ratio of intensities in three spectra is used to identify 927 lines due to absorption by H218O. Intensities and self-broadening parameters are derived for these lines. Using theoretical linelists, comparisons with previously assigned H216O spectra, and automatic searches for combination differences, 747 lines are assigned. These lines belong to 14 vibrational states in the 3ν+δ and 4ν polyads. Newly determined H218O vibrational band origins include 4ν1 at 13 793.09 cm−1, 3ν1+ν3 at 13 795.40 cm−1, 2ν1+2ν3 at 14 188.82 cm−1, ν1+3ν3 at 14 276.34 cm−1, and 2ν2+2ν2+ν3 at 13 612.71 cm−1. These results are compared with data in HITRAN. 相似文献