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排序方式: 共有228条查询结果,搜索用时 265 毫秒
1.
多氮杂大环与许多金属离子能形成稳定的络合物。由于氮原子是三价的,因而多氮杂大环比冠醚具有更有利的结构;如果再导入羧基、膦酸基以及其他的亲水基团,则可得到一系列能形成水溶性金属络合物的配体。其中某些金属(如铜、钇等)的络合物在人体生理条件下表现出很好的稳定性,结合单原抗体技术的应用,这炎络合物在医疗、诊断方面有实用性。本文简单介绍某些代表性络合物的制备方法、物理性能和可能的应用。 相似文献
2.
Shota Niibayashi 《Journal of organometallic chemistry》2005,690(2):276-285
A series of titanocene(III) alkoxides L2Ti(III)OR where L = Cp, R = Et(1b), tBu(1a), 2,6-Me2C6H3(1c), 2,6-tBu2-4-Me-C6H2(1d), or L = Cp*, R = Me(2e), tBu(2a), Ph(2f) was synthesized and subjected to reaction with [CpM(CO)3]2 [M = Mo, W], [CpRu(CO)2]2, and Co2(CO)8. The Ti(III) precursors 1a, 1c, 2a, 2e, and 2f reacted with [CpM(CO)3]2 [M = Mo, W] to form heterobimetallic complexes L2Ti(OR)(μ-OC)(CO)2MCp [M = Mo, W], of which Ti and M are linked by an isocarbonyl bridge. Reactions of these Ti(III) complexes with Co2(CO)8 resulted in formation of Ti-Co1 heterobimetallic complexes, from 2a, 2e, or 2f, or Ti-Co3 tetrametallic complexes, Cp2Ti(OtBu)(μ-OC)Co3(CO)9 from 1a, 1b, or 1c. The products were characterized by NMR, IR, and X-ray crystallography. Reaction mechanisms were proposed from these results, in particular, from steric/electronic effects of titanium alkoxides. 相似文献
3.
A novel method for determination of inorganic oxyanions by electrospray ionization mass spectrometry using dehydration reactions 下载免费PDF全文
Hirochika Kojima Shota Kurihara Yoshito Watanabe Koki Iwamaru Kiichi Sato Kin‐ichi Tsunoda Hiroki Hotta 《Journal of mass spectrometry : JMS》2016,51(2):123-131
Novel methods for the determination of inorganic oxyanions by electrospray (ES) ionization mass spectrometry have been developed using dehydration reactions between oxyanions and carboxylic acids at the ES interface. Twelve oxyanions (VO3?, CrO42?, MoO42?, WO42?, BO33?, SiO32?, SiO44?, AsO44?, AsO2?, SeO42?, SeO32? and NO2?), out of 16 tested, reacted with at least one of four aminopolycarboxylic acids, i.e. iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), trans‐1,2‐diaminocyclohexane‐N,N,N′,N′‐tetraacetic acid and triethylenetetramine‐N,N,N′,N″,N′″,N′″‐hexaacetic acid, at the ES interface to produce the dehydration products that gave intense mass ion responses, sufficient for trace analysis. As examples, trace determinations of CrVI and silica in water samples were achieved after online ion exchange chromatography, where the dehydration product of CrO42? and NTA (m/z 290) and that of SiO44? and IDA (m/z 192) were measured. The limits of detection of the respective methods were 17 nM (0.83 ng Cr/ml) for CrVI and 0.17 μM (4.8 ng Si/mL) for SiO44?. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
4.
5,11-Diazadibenzo[hi,qr]tetracene: Synthesis,Properties, and Reactivity toward Nucleophilic Reagents
Dr. Keisuke Fujimoto Satoshi Takimoto Shota Masuda Dr. Toshiyasu Inuzuka Kazutaka Sanada Prof. Dr. Masami Sakamoto Prof. Dr. Masaki Takahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(35):8951-8955
5,11-Diazadibenzo[hi,qr]tetracene was synthesized as a new nitrogen-substituted polycyclic heteroaromatic compound by Pd-catalyzed cycloisomerization of an alkyne precursor followed by oxidative cyclization with bis(trifluoroacetoxy)iodobenzene. The substitution of imine-type nitrogen atoms significantly enhanced its electron-accepting character and facilitated the direct nucleophilic addition of arylamines under strongly basic conditions to afford the desired amino-substituted products. The introduction of amino groups induced a remarkable red-shift in their absorption spectra; the tetrasubstituted product exhibited intense near-infrared absorbing property. Furthermore, the π-electronic system, which includes a redox-active 1,4-diazabutadiene moiety, underwent reversible interconversion to its corresponding reduced form upon reduction with NaBH4 and aerobic oxidation. 相似文献
5.
The initial stage of electrodeposition of manganese dioxide has been studied on the platinum disk electrode and on the ring-disk electrode. Two current maxima were observed on the anodic voltammograms. It has been shown that the first rise in the current is associated with the formation of manganese dioxide (MD) nuclei on the electrode surface, and the second with their growth at the border between MnO2 and bare platinum due to an increase in the perimeter of the nuclei. Electrodeposition on bare platinum proceeds at a higher rate than on the surface of growing MD. This is explained by the difference in the reaction mechanisms on these substrates. The first stage of the process on the growing MD is the chemisorption of Mn(II) ions with the formation of Mn(III) ions, which are then electrochemically oxidized to MD. Chemisorption is the slowest step in the whole process. 相似文献
6.
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
7.
Nicolas Zigon Manabu Hoshino Shota Yoshioka Yasuhide Inokuma Makoto Fujita 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(31):9161-9165
Crystal structures of α‐humulene, a cyclic sesquiterpene, and its oxidized subproducts, were analyzed by the crystalline sponge method. Regio‐ and stereochemistry, including absolute configuration when a chiral oxidant was applied, and the stable conformations of all the scaffold‐related compounds were successfully determined for samples on a 5–50 μg scale. 相似文献
8.
Katsuya Sako Toshiaki Kakehi Shota Nakano Hiroyuki Oku Xu Feng Shen Tetsuo Iwanaga Manami Yoshikawa Kouta Sugahara Shinji Toyota Hiroyuki Takemura Teruo Shinmyozu Michito Shiotsuka Hitoshi Tatemitsu 《Tetrahedron letters》2014
Two novel redox-active 1,3-dithiole (DT) ring-fused 4,5-diazafluorene ligands with crown ether moieties (L1 and L2) were synthesized and characterized. The crystal structure of L1 was studied. The electrochemical and spectroscopic properties of these new ligands, as well as the corresponding bis(bipyridine)ruthenium(II) complexes [4: Ru L1(bpy)2 and 5: Ru L2(bpy)2], were also been investigated. 相似文献
9.
Site‐Selective CH Borylation of Quinolines at the C8 Position Catalyzed by a Silica‐Supported Phosphane–Iridium System 下载免费PDF全文
Shota Konishi Dr. Soichiro Kawamorita Dr. Tomohiro Iwai Prof. Patrick G. Steel Prof. Dr. Todd B. Marder Prof. Dr. Masaya Sawamura 《化学:亚洲杂志》2014,9(2):434-438
Site‐selective C? H borylation of quinoline derivatives at the C8 position has been achieved by using a heterogeneous Ir catalyst system based on a silica‐supported cage‐type monophosphane ligand SMAP. The efficient synthesis of a corticotropin‐releasing factor1 (CRF1) receptor antagonist based on a late‐stage C? H borylation strategy demonstrates the utility of the C8 borylation reaction. 相似文献
10.
Sayoko Nagashima Shota Furukawa Satoshi Kamiguchi Ryu Kajio Hiroshi Nagashima Aritomo Yamaguchi Masayuki Shirai Hideki Kurokawa Teiji Chihara 《Journal of Cluster Science》2014,25(5):1203-1224
A series of molecular rhenium sulfide clusters [Re6S8(OH)6?n (H2O) n ](4?n)? (n = 0, 2, 4, 6) catalyze dehydrogenation of alcohols, and hydrogenation of ketones and olefins in a hydrogen stream at 350 °C. The catalytic activities of the dianionic and neutral clusters (n = 2, 4) are lower than those of tetraanionic and dicationic clusters (n = 0, 6) for all the reactions. When 1,4-butanediol is allowed to react over K4[Re6S8(OH)6], dehydrogenation proceeds to yield 2-hydroxytetrahydrofuran and successively γ-butyrolactone above 300 °C. Over [Re6S8(H2O)6]SO4 dehydration proceeds to yield tetrahydrofuran above 250 °C. The thermal activation mechanisms of these clusters were studied by powder X-ray diffraction analyses, Raman spectrometry, extended X-ray absorption fine structure spectrometry, thermogravimetry, and differential thermal analyses. The catalytically active site of K4[Re6S8(OH)6] is an uncoordinated metal site (Lewis acid site) developed by the loss of a water molecule from two hydroxo ligands. The active site of [Re6S8(H2O)6]SO4 is a Brønsted acid site; the anhydrous aqua cluster dication disproportionates to a hydroxo cluster monocation and a proton. Both of the octahedral cluster frameworks are retained up to 500 °C. 相似文献