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91.
Murat Çelik Cemalettin Alp M. Serdar Gültekin Metin Balci 《Tetrahedron letters》2006,47(22):3659-3663
1,2- and 1,3-Bis(trifluoroacetoxy) alcohols are easily obtained from the one-pot reaction of alkenes with phenyliodine(III) bis(trifluoroacetate) (PIFA) in the absence of any additive or catalyst. The products were converted into the corresponding diols by ammonolysis. The use of bicyclic alkenes has shown that rearranged 1,3-diacetoxy alcohols are mostly formed as the major products. 相似文献
92.
This is the first of a series of papers on the perturbative treatment of screened coulomb potential systems in quantum mechanics. Its content is mainly devoted to the evaluation of first four terms in a convergent energy expansion of Yukawa potential. For this purpose, a weighted eigenvalue problem of Laplacian accompanied by spherical symmetry is employed to find the inverse of the Schrödinger operator for unperturbed case (which is assumed to be the Hamiltonian of Hydrogen-like systems). Some very encouraging numerical results are also given for illustrative purposes. 相似文献
93.
In this work, a new method to factorize certain evolution operators into an infinite product of simple evolution operators is presented. The method uses Lie operator algebra and the evolution operators are restricted to exponential form. The argument of these forms is a first-order linear partial differential operator. The method has broad applications, including the areas of sensitivity analysis, the solution of ordinary differential equations, and the solution of Liouville's equation. A sequence of -approximants is generated to represent the Lie operators. Under certain conditions, the convergence rate of the -approximant sequences is remarkably high. This work presents the general formulation of the scheme and some simple illustrative examples. Investigation of convergence properties is given in a companion paper.Supported by the Department of Energy. 相似文献
94.
The coupling of ferrocenyl alkynes with cyclopropylcarbene-chromium complex leads to ferrocenyl-substituted 2-cyclopentenones with or without a hydroxy substituent, namely 4-cyclopentene-1,3-diones, 2-cyclobutenones, and α,β-unsaturated aldehydes in varying amounts. The reaction initially produces a cyclopentadienone intermediate, then to the double bond of which, bearing a ferrocenyl group, addition of water occurs to afford hydroxy-substituted 2-cyclopentenones. In all the products, the hydroxy group ends up α to the ferrocenyl moiety. In contrast, where no addition of water occurs, the alkenic bond is reduced to give 2-cyclopentenones. A secondary reaction product, namely 4-cyclopentene-1,3-dione, is formed by hydrolysis of the cyclopentadienone intermediates. 相似文献
95.
Patrick Degen Michael Paulus Elena Zwar Victoria Jakobi Susanne Dogan Metin Tolan Heinz Rehage 《Surface and interface analysis : SIA》2019,51(11):1051-1058
The self-organization process of polysaccharide alginate with different cationic surfactants at the water-air interface was investigated over a wide concentration regime. The changes of surface properties determined by surface tension measurements, surface rheology, and X-ray reflectivity are correlated with changes of bulk properties measured by turbidity, light scattering, and zeta potential measurements. We demonstrate that the interactions between the alginate and cationic surfactants result in significant changes of bulk and interfacial properties. The results of surface shear experiments point to the existence of highly viscoelastic interfacial films. In combination with X-ray reflectivity, we demonstrate that these rheological features are related to polymer-surfactant associations at the interface. In the regime of high surfactant concentrations, we observed the existence of multilayer structures. 相似文献
96.
In this paper, we build on our previous research on probabilistic foundations of dynamical systems and introduce a theory of linear representation for ordinary differential equations. The theory is developed for explicit ODEs and can be further extended to cover implicit cases. In this report, we investigate the case of a canonical single unknown autonomous system. First we construct a linear representation to get an infinite linear ODE set with a constant coefficient matrix which can be transformed into an upper triangular form. Then we find its approximate truncated solutions. We describe a number of properties of the theory using this framework. The companion of this paper expands this canonical approach to cover multidimensional cases using the theory of folded arrays which is another line of research established by our research group. 相似文献
97.
We construct the inhomogeneous quantum groups with continuous parameters which leave the boson and fermion algebras of field
theory invariant. 相似文献
98.
The phenyl‐substituted conduritol B 8 was prepared in racemic form in a five‐step sequence starting from 2‐phenyl‐1,4‐benzoquinone ( 10 ) (Scheme 1). The reaction mechanism of the key step 12b → 13 is discussed (Scheme 2). 相似文献
99.
We present herein a new nanocatalyst, namely binary CuPt alloy nanoparticles (NPs) supported on reduced graphene oxide (CuPt‐rGO), as a highly active heterogeneous catalyst for the transfer hydrogenation (TH) protocol that is demonstrated to be applicable over the reduction of various unsaturated organic compounds (olefins, aldehydes/ketones and nitroarenes) in aqueous solutions at room temperature. CuPt alloy NPs were synthesized by the co‐reduction of metal (II) acetylacetonates by borane‐tert‐butylamine (BTB) complex in hot oleylamine (OAm) solution and then assembled on reduced graphene oxide (rGO) via ultrasonic‐assisted liquid phase self‐assembly method. The structure of yielded CuPt NPs and CuPt‐rGO nanocatalyst were characterized by TEM, XRD and ICP‐MS. The activity of Cu7Pt3‐rGO nanocatalysts were then tested for the THs that were conducted in a commercially available high‐pressure tube using water as sole solvent and ammonia borane as a hydrogen donor at room temperature. The presented catalytic TH protocol was successfully applied over nitroarenes, olefines and aldehydes/ketones, and all the tested compounds were converted to corresponding reduction products with the yields reaching up to 99% under ambient conditions. Moreover, the Cu7Pt3‐rGO nanocatalyst was also reusable in the TH by providing 99% yield after five consecutive runs in TH of nitrobenzene as an example. 相似文献
100.
Yavuz Abdulcabbar Kaplan Kaan Bedir Metin 《Journal of Solid State Electrochemistry》2022,26(6):1333-1347
Journal of Solid State Electrochemistry - The motivation of this study is to understand the usability of annealed stainless steel mesh obtained by a straightforward method for energy storage... 相似文献