排序方式: 共有159条查询结果,搜索用时 15 毫秒
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J. D'Ans G. Dorfmüller J. Großfeld H. Leonhardt Ph. Naoúm A. Berthman G. Jayme R. Korn F. Burgstaller H. Sommer H. Mendrzyk W. Weltzien Karin Windeck-Schulze E. Ristenpart E. Sauer A. Küntzel S. Reissinger W. Esch W. Toeldte H. P. Kaufmann S. Funke W. Halden B. Wurzschmitt H. Thomas E. van Hulle E. Messmer P. Rabe H. van Haasy G. Hamann T. Berglund M. Sartori Gebührenaussehuß für chemische Arbeiten 《Analytical and bioanalytical chemistry》1940,119(11-12):422-425
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Inamo M Matsubara N Nakajima K Iwayama TS Okimi H Hoshino M 《Inorganic chemistry》2005,44(18):6445-6455
The photoreaction of the chromium(III) octaethylpoprhyrin complex, [Cr(OEP)(Cl)(L)] (L = H2O, Py, OPPh3), in dichloromethane was studied using laser flash photolysis technique. Laser irradiation causes the generation of a coordinately unsaturated intermediate [Cr(OEP)(Cl)], which reacts with ligands in solution to give the parent complex, [Cr(OEP)(Cl)(L)], or a transient species, [Cr(OEP)(Cl)(H2O)], when L = Py or OPPh3. Once produced [Cr(OEP)(Cl)(H2O)] eventually exchanges the axial H2O ligand with L to regenerate [Cr(OEP)(Cl)(L)]. The kinetics of the axial ligand substitution reaction was followed spectrophotometrically, and the ligand-concentration dependence of the ligand exchange rate revealed that the reaction occurs via a limited dissociative mechanism. The photoreaction of [Cr(OEP)(Cl)(OPPh3)] containing excess PPh3 in the bulk solution leads to the unfavorable coordination of the PPh3 molecule to the chromium ion to give a transient complex, [Cr(OEP)(Cl)(PPh3)]. The dynamic and thermodynamic properties of [Cr(OEP)(Cl)(PPh3)] in solution are discussed on the basis of the kinetic parameters of the dissociation and association reactions of the PPh3 ligand together with the steric aspect of the molecular structure of the related complexes. 相似文献
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In this paper, we are presenting a proposal for new modified
algorithms for RRGMRES and AGMRES. It is known that RRGMRES and
AGMRES are viable methods for solving linear discrete ill-posed
problems. In this paper we have focused on the residual norm and
have come up with two improvements where successive updates and the
stabilization of decreases for the residual norm improve performance
respectively. Our numerical experiments confirm that our improved
algorithms are effective for linear discrete ill-posed problems. 相似文献
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Beibei Zhou Tengwu Zeng Zhao‐Lin Shi Gen Zhang Satoshi Horike Yue‐Biao Zhang 《化学:亚洲杂志》2019,14(20):3552-3556
The function of allosteric enzymes can be activated or inhibited through binding of specific effector molecules. Herein, we describe how the skeletal deformation, pore configuration, and ultimately adsorptive behavior of a dynamic metal–organic framework (MOF), (Me2NH2)[In(atp)]2 (in which atp=2‐aminoterephthalate), are controlled by the allocation and orientation of its counter ions triggered by the inclusion/removal of different guest molecules. The power of such allosteric control in MOFs is highlighted through the optimization of the hydrocarbon separation performance by achieving multiple pore configurations but without altering the chemical composition. 相似文献
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D Umeyama S Horike M Inukai T Itakura S Kitagawa 《Journal of the American Chemical Society》2012,134(30):12780-12785
We synthesized a coordination polymer consisting of Zn(2+), 1,2,4-triazole, and orthophosphates, and demonstrated for the first time intrinsic proton conduction by a coordination network. The compound has a two-dimensional layered structure with extended hydrogen bonds between the layers. It shows intrinsic proton conductivity along the direction parallel to the layers, as elucidated by impedance studies of powder and single crystals. From the low activation energy for proton hopping, the conduction mechanism was found to be of the Grotthuss fashion. The hopping is promoted by rotation of phosphate ligands, which are aligned on the layers at appropriate intervals. 相似文献
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Takashi Yamazaki Yohsuke Watanabe Nao Yoshida Tomoko Kawasaki-Takasuka 《Tetrahedron》2012,68(33):6665-6673
Empirical information on the acidity of the propargylic proton from our previous work allowed us to develop novel synthetic transformations of readily available terminally trifluoromethylated propargylic alcohols 1 into the corresponding allenyl tosylates 3a, 1-tosyloxy- or 1-acyloxy-4,4,4-trifluorobutan-2-ones 4, and 2-(2,2,2-trifluoroethyl)prop-2-en-1-ones 5, which was enabled by such common bases as NaOH and tertiary amines for affecting ready abstraction of this proton. 相似文献