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121.
Baya M Houghton J Daran JC Poli R Male L Albinati A Gutman M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(19):5347-5359
Complexes [MoCp(#)(PMe(3))(2)H(3)] (Cp(#)=1,2,4-C(5)H(2)tBu(3), 2 a; C(5)HiPr(4), 2 b) have been synthesized from the corresponding compounds [MoCp(#)Cl(4)] (1 a, 1 b) and fully characterized, including by X-ray crystallography and by a neutron diffraction study for 2 a. Protonation of 2 a led to complex [Mo(1,2,4-C(5)H(2)tBu(3))(PMe(3))(2)H(4)](+) (3 a) in THF and to [Mo(1,2,4-C(5)H(2)tBu(3))(PMe(3))(2)(MeCN)H(2)](+) (4 a) in MeCN. Complex 4 b analogously derives from protonation of 2 b in MeCN, whereas the tetrahydride complex 3 b is unstable. One-electron oxidation of 2 a and 2 b by [FeCp(2)]PF(6) produces the EPR-active 17-electron complexes 2 a(+) and 2 b(+). The former is thermally more stable than the latter and could be crystallographically characterized as the PF(6) (-) salt by X-ray diffraction, providing evidence for the presence of a stretched dihydrogen ligand (H...H=1.36(6) angstroms). Controlled thermal decomposition of 2 a(+) yielded the product of H(2) elimination, the 15-electron monohydride complex [Mo(1,2,4-C(5)H(2)tBu(3))(PMe(3))(2)H]PF(6) (5 a), which was characterized by X-ray crystallography and by EPR spectroscopy at liquid He temperature. The compound establishes an equilibrium with the solvent adduct in THF. An electrochemical study by cyclic voltammetry provides further evidence for a rapid H(2) elimination process from the 17-electron complexes. In contrast to the previously investigated [MoCp*(dppe)H(3)](+) system (dppe=1,2-bis(diphenylphosphino)ethane; Cp*=pentamethylcyclopentadienyl), the decomposition of 2 a(+) by H(2) substitution with a solvent molecule appears to follow a dissociative pathway in MeCN. 相似文献
122.
123.
Dr. Kazunobu Igawa Daisuke Yoshihiro Yusuke Abe Prof. Dr. Katsuhiko Tomooka 《Angewandte Chemie (International ed. in English)》2016,55(19):5814-5818
A variety of functionalized silacyclopentanes were synthesized by highly enantioselective β‐eliminations of silacyclopentene oxides followed by stereospecific transformations. The reaction mechanism of the β‐elimination was elucidated by DFT calculations. An in vitro biological assay with an oxy‐functionalized silacyclopentane showed substantial binding to a serotonin receptor protein. 相似文献
124.
Dr. Kenichi Kato Dr. Hidetaka Kasai Dr. Akihiro Hori Prof. Dr. Masaki Takata Prof. Dr. Hiroshi Tanaka Prof. Dr. Susumu Kitagawa Akira Kobayashi Dr. Nobuki Ozawa Prof. Dr. Momoji Kubo Dr. Hidekazu Arikawa Prof. Dr. Tatsuya Takeguchi Dr. Masaaki Sadakiyo Prof. Dr. Miho Yamauchi 《化学:亚洲杂志》2016,11(10):1537-1541
The layered P2‐NaxMO2 (M: transition metal) system has been widely recognized as electronic or mixed conductor. Here, we demonstrate that Co vacancies in P2‐NaxCoO2 created by hydrogen reductive elimination lead to an ionic conductivity of 0.045 S cm?1 at 25 °C. Using in situ synchrotron X‐ray powder diffraction and Raman spectroscopy, the composition of the superionic conduction phase is evaluated to be Na0.61(H3O)0.18Co0.93O2. Electromotive force measurements as well as molecular dynamics simulations indicate that the ion conducting species is proton rather than hydroxide ion. The fact that the Co‐stoichiometric compound Nax(H3O)yCoO2 does not exhibit any significant ionic conductivity proves that Co vacancies are essential for the occurrence of superionic conductivity. 相似文献
125.
Inside Cover: Superionic Conduction in Co‐Vacant P2‐NaxCoO2 Created by Hydrogen Reductive Elimination (Chem. Asian J. 10/2016) 下载免费PDF全文
Dr. Kenichi Kato Dr. Hidetaka Kasai Dr. Akihiro Hori Prof. Dr. Masaki Takata Prof. Dr. Hiroshi Tanaka Prof. Dr. Susumu Kitagawa Akira Kobayashi Dr. Nobuki Ozawa Prof. Dr. Momoji Kubo Dr. Hidekazu Arikawa Prof. Dr. Tatsuya Takeguchi Dr. Masaaki Sadakiyo Prof. Dr. Miho Yamauchi 《化学:亚洲杂志》2016,11(10):1465-1465
126.
Estefanía Gioria Dr. Juan del Pozo Dr. Jesús M. Martínez‐Ilarduya Prof. Dr. Pablo Espinet 《Angewandte Chemie (International ed. in English)》2016,55(42):13276-13280
A Pd complex, cis‐[Pd(C6F5)2(THF)2] ( 1 ), is proposed as a useful touchstone for direct and simple experimental measurement of the relative ability of ancillary ligands to induce C?C coupling. Interestingly, 1 is also a good alternative to other precatalysts used to produce Pd0L. Complex 1 ranks the coupling ability of some popular ligands in the order PtBu3>o‐TolPEWO‐F≈tBuXPhos>P(C6F5)3≈PhPEWO‐F>P(o‐Tol)3≈THF≈tBuBrettPhos?Xantphos≈PhPEWO‐H?PPh3 according to their initial coupling rates, whereas their efficiency, depending on competitive hydrolysis, is ranked tBuXPhos≈PtBu3≈o‐TolPEWO‐F>PhPEWO‐F>P(C6F5)3?tBuBrettPhos>THF≈P(o‐Tol)3>Xantphos>PhPEWO‐H?PPh3. This “meter” also detects some other possible virtues or complications of ligands such as tBuXPhos or tBuBrettPhos. 相似文献
127.
烟叶和烟草料液中氨基酸的直接检测及碳水化合物的去除 总被引:3,自引:0,他引:3
建立了高效阴离子交换色谱-积分脉冲安培法(HPAEC-IPAD)直接检测烟叶和烟草料液中氨基酸的方法。利用离线除糖的方法,去除烟叶和烟草料液中大量干扰糖类,包括葡萄糖、果糖和蔗糖及麦芽低聚糖等。采用AminoPac PA10阴离子交换柱,以NaOH和NaAc的强碱性溶液为淋洗液,采用梯度洗脱,流速为0.25 mL/min;积分脉冲安培法对氨基酸进行检测,回收率可达76%~105%。此方法可以有效的解决烟叶、烟草料液等含糖量高的样品中糖类化合物的干扰,对氨基酸实现灵敏、准确的定量分析。 相似文献
128.
Huseyin Bekir Yildiz Jaime Castillo Dmitrii A. Guschin Levent Toppare Wolfgang Schuhmann 《Mikrochimica acta》2007,159(1-2):27-34
An amperometric biosensor for the detection of phenolic compounds was developed based on the immobilization of tyrosinase
within an Os-complex functionalized electrodeposition polymer. Integration of tyrosinase within the redox polymer assures
efficient catechol recycling between the enzyme and the polymer bound redox sites. The non-manual immobilization procedure
improves the reproducibility of fabrication process, greatly reduces the desorption of the enzyme from the immobilization
layer, and, most importantly prevents fast inactivation of the enzyme by its substrate due to fast redox cycling.
A two-layer sensor architecture was developed involving ascorbic acid oxidase entrapped within an electrodeposition polymer
in a second layer on top of the redox polymer/tyrosinase layer. Using this sensor architecture it was possible to eliminate
the current interference arising from direct ascorbate oxidation up to a concentration of 630 μM ascorbic acid. The effects
of the polymer thickness, the enzyme/polymer ratio, and the applied potential were evaluated with respect to optimal sensor
properties. The sensitivity of the optimized sensors for catechol was 6.1 nA μM−1 with a detection limit of 10 nM, and for phenol 0.15 nA μM−1 with a detection limit of 100 nM. 相似文献
129.
S. Stupnikova E. Petushkova D. Muceniece V. Lūsis 《Chemistry of Heterocyclic Compounds》2007,43(1):41-49
The recyclization of 1,4-dihydropyridines in aqueous-alcoholic hydrochloric acid medium proceeds with cleavage of a C-N bond
and pyridine ring opening. Cyclohexenone derivatives are formed as a result of the subsequent intramolecular crotonic condensation
of the acyclic intermediate. The leaving carbonyl substituents depart simultaneously with recyclization, depending on the
acidity of the reaction medium.
Dedicated to Prof. Dr. E. Lukevics on the occasion of his 70th birthday.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 49–58, January, 2007. 相似文献
130.
Paolo Calvini Andrea Gorassini Giorgio Luciano Enrico Franceschi 《Vibrational Spectroscopy》2006,40(2):177-183
Cellulose paper (Whatman no.1, chromatographic grade) was oxidised with 0.1 M sodium metaperiodate at different oxidation levels (0–11 days at room temperature), and analysed with FTIR before and after chemical treatments (reduction, further oxidation, alkaline hydrolysis). The deconvolution of infrared data allowed us to verify that periodate oxidises cellulose in isolated domains, leading to the decrease of crystallinity, in agreement with the results of wide angle X-ray scattering (WAXS). In particular, the alkaline hydrolysis (β-alkoxy fragmentation) followed by mild acid treatment removed the oxidised groups and recovered most of the crystallinity of cellulose, as determined by the FTIR crystallinity index. 相似文献