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81.
Karsten Sonnenberg Patrick Pröhm Dr. Nico Schwarze Dr. Carsten Müller Dr. Helmut Beckers Prof. Dr. Sebastian Riedel 《Angewandte Chemie (International ed. in English)》2018,57(29):9136-9140
For decades the chemistry of polyhalides was dominated by polyiodides and more recently also by an increasing number of polybromides. However, apart from a few structures containing trichloride anions and a single report on an octachloride dianion, [Cl8]2?, polychlorine compounds such as polychloride anions are unknown. Herein, we report on the synthesis and investigation of large polychloride monoanions such as [Cl11]? found in [AsPh4][Cl11], [PPh4][Cl11], and [PNP][Cl11]?Cl2, and [Cl13]? obtained in [PNP][Cl13]. The polychloride dianion [Cl12]2? has been obtained in [NMe3Ph]2[Cl12]. The novel compounds have been thoroughly characterized by NMR spectroscopy, single‐crystal Raman spectroscopy, and single‐crystal X‐ray diffraction. The assignment of their spectra is supported by molecular and periodic solid‐state quantum‐chemical calculations. 相似文献
82.
Critical constants of pure fluids (as important reference data in constructing vapour-liquid phase diagrams and basic input of various estimation methods) were determined for systems of non-spherical Kihara molecules; values of the critical temperature, density, compression factor and pressure of fluids composed of prolate and oblate molecules were evaluated from the fourth-order virial expansion. The second and third virial coefficients of the Kihara molecules were determined by applying the recently proposed method in which the effect of molecular core geometry and functional dependence of a pair interaction on the surface-surface distance are factorized and the former contribution determined from a formula for the corresponding hard convex body virial coefficient. The virial expansion for non-spherical Kihara molecules is applied to determine the critical constants of n-alkanes (methane to octane) and cyclic hydrocarbons (cyclopentane, cyclohexane, benzene and naphthalene); a fair agreement with experimental data was found. 相似文献
83.
A Highly K+‐Selective Fluorescent Probe – Tuning the K+‐Complex Stability and the K+/Na+ Selectivity by Varying the Lariat‐Alkoxy Unit of a Phenylaza[18]crown‐6 Ionophore
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Dr. Thomas Schwarze Radu Schneider Janine Riemer Prof. Dr. Hans‐Jürgen Holdt 《化学:亚洲杂志》2016,11(2):241-247
A desirable goal is to synthesize easily accessible and highly K+/Na+‐selective fluoroionophores to monitor physiological K+ levels in vitro and in vivo. Therefore, highly K+/Na+‐selective ionophores have to be developed. Herein, we obtained in a sequence of only four synthetic steps a set of K+‐responsive fluorescent probes 4 , 5 and 6 . In a systematic study, we investigated the influence of the alkoxy substitution in ortho position of the aniline moiety in π‐conjugated aniline‐1,2,3‐triazole‐coumarin‐fluoroionophores 4 , 5 and 6 [R=MeO ( 4 ), EtO ( 5 ) and iPrO ( 6 )] towards the K+‐complex stability and K+/Na+ selectivity. The highest K+‐complex stability showed fluoroionophore 4 with a dissociation constant Kd of 19 mm , but the Kd value increases to 31 mm in combined K+/Na+ solutions, indicating a poor K+/Na+ selectivity. By contrast, 6 showed even in the presence of competitive Na+ ions equal Kd values (KdK+=45 mm and KdK+/Na+=45 mm ) and equal K+‐induced fluorescence enhancement factors (FEFs=2.3). Thus, the fluorescent probe 6 showed an outstanding K+/Na+ selectivity and is a suitable fluorescent tool to measure physiological K+ levels in the range of 10–80 mm in vitro. Further, the isopropoxy‐substituted N‐phenylaza[18]crown‐6 ionophore in 6 is a highly K+‐selective building block with a feasible synthetic route. 相似文献
84.
For systems of Kihara molecules with circular cores, the values of the reduced critical constants were determined from the fourth-order virial expansion as functions of the core diameter/thickness ratio. From expressions for the reduced functions both for the oblate and prolate shapes, the values of critical constants of four cyclic hydrocarbons and four branched alkanes were evaluated and compared with the experimental data and values obtained from the perturbation theory. 相似文献
85.
86.
W. Leithe P. Schwarze L. Kofler R. Opfer-Schaum und G. Gorbach 《Fresenius' Journal of Analytical Chemistry》1943,125(5-6):214-215
Ohne Zusammenfassung 相似文献
87.
88.
This contribution deals with a new finite element formulation for the efficient simulation of forming processes, in particular for sheet metal forming. For that goal an isoparametric eight-node solid-shell formulation with linear ansatz functions is developed in which the undesirable effect of locking is completely eliminated. So only one element over the thickness is necessary which increases noticeably the numerical efficiency. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
89.
H. Bothe U. Derigs K. -P. Kistner J. Schwarze H. Noltemeier A. Jaeger R. Weber S. Albers V. Steinecke W. P. Schmidt 《Mathematical Methods of Operations Research》1979,23(6):B183-B190
Ohne Zusammenfassung 相似文献
90.
C. A. Ayre D. D. van Slyke H. O. Calvery H. B. Vickery C. S. Leavenworth W. S. Ferguson G. Bishop W. J. Peterson J. S. Hughes H. F. Freeman O. Flieg G. A. Guanzon W. M. Sandstrom G. S. Fraps A. D. Dickson H. Otterson K. P. Link E. Anderson F. W. Norris C. E. Resch Kennedy H. K. Nason F. E. Nottbohm Fr. Mayer E. Rauterberg E. Knippenberg P. Schwarze E. Szonntag W. Lepper W. Stollenwerk E. Vahlkampf T. Wijkström 《Analytical and bioanalytical chemistry》1939,118(5-6):229-238