排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
Sameer Chavda Elliot Coulbeck Gregory S. Coumbarides Marco Dingjan Jason Eames Stephanos Ghilagaber Yonas Yohannes 《Tetrahedron: Asymmetry》2006,17(24):3386-3399
The resolution of 2-phenylpropanoyl chloride using an equimolar combination of quasi-enantiomeric oxazolidinones is discussed. The levels of diastereoselectivity were found to be dependent upon the structural nature of the metallated oxazolidinone, temperature and metal counter-ion. 相似文献
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Dr. Girish D. Salian Dr. Jonathan Højberg Dr. Christian Fink Elkjær Yonas Tesfamhret Dr. Guiomar Hernández Dr. Matthew J. Lacey Assoc. Prof. Dr. Reza Younesi 《ChemistryOpen》2022,11(6):e202200065
Two water-soluble binders of carboxymethyl cellulose (CMC) and sodium alginate (SA) have been studied in comparison with N-methylpyrrolidone-soluble poly(vinylidene difluoride–co-hexafluoropropylene) (PVdF-HFP) to understand their effect on the electrochemical performance of a high-voltage lithium nickel manganese oxide (LNMO) cathode. The electrochemical performance has been investigated in full cells using a Li4Ti5O12 (LTO) anode. At room temperature, LNMO cathodes prepared with aqueous binders provided a similar electrochemical performance as those prepared with PVdF-HFP. However, at 55 °C, the full cells containing LNMO with the aqueous binders showed higher cycling stability. The results are supported by intermittent current interruption resistance measurements, wherein the electrodes with SA showed lower resistance. The surface layer formed on the electrodes after cycling has been characterized by X-ray photoelectron spectroscopy. The amount of transition metal dissolutions was comparable for all three cells. However, the amount of hydrogen fluoride (HF) content in the electrolyte cycled at 55 °C is lower in the cell with the SA binder. These results suggest that use of water-soluble binders could provide a practical and more sustainable alternative to PVdF-based binders for the fabrication of LNMO electrodes. 相似文献
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Gregory S. Coumbarides Jason Eames Anthony Flinn Yonas Yohannes 《Tetrahedron letters》2005,46(16):2897-2902
The parallel kinetic resolution of pentafluorophenyl 2-phenylpropionate using an equimolar combination of quasi-enantiomeric oxazolidinones is discussed. The levels of diastereocontrol were excellent leading to separable quasi-enantiomeric syn-oxazolidinone adducts in good yield. 相似文献
4.
Najla Al ShayeSameer Chavda Elliot CoulbeckJason Eames Yonas Yohannes 《Tetrahedron: Asymmetry》2011,22(4):439-463
The parallel resolution of racemic pentafluorophenyl 2-aryl/phenylpropanoates and butanoates using an equimolar combination of quasi-enantiomeric Evans oxazolidin-2-ones is discussed. The levels of diastereoselectivity were excellent (>90% de) leading to separable quasi-enantiomeric oxazolidin-2-ones in good yield. This methodology was used to resolve a series of structurally related 2-aryl/phenylpropanoic and butanoic acids. 相似文献
5.
Yonas Belay Louis-Charl Coetzee D. Bradley G. Williams Alfred Muller 《Tetrahedron letters》2019,60(6):501-503
Copper catalysed click reactions are excellent tools to generate various 1,2,3-triazole linked polytopic aromatic carboxylates. The general reaction route involves protection of the carboxylates before proceeding with the click reaction. These polycarboxylate azoles are conveniently prepared for potential utility as novel key building blocks for metal organic frameworks. In one case, the ligand crystallises into a solid structure containing 1D, 2D and 3D features, based on a zigzag 1D structure, a ‘chicken mesh’-like 2D structure and a 3D structure with very well-defined channels. 相似文献
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Marielba Rojas Yonas B. Abraham Natalie A. W. Holzwarth Robert J. Plemmons 《PAMM》2007,7(1):2060001-2060002
We propose a new approach based on surrogate modeling for geometry optimization in material design. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Najla Al ShayeDavid M. Benoit Sameer Chavda Elliot CoulbeckMarco Dingjan Jason Eames Yonas Yohannes 《Tetrahedron: Asymmetry》2011,22(4):413-438
The kinetic, mutual and parallel resolution of a series of structurally related active esters derived from 2-phenylpropanoic acid using a combination of quasi-enantiomeric oxazolidin-2-ones is discussed. 相似文献
10.
1,3‐Ninhydrin dihydrazone featuring an R44(12) motif with symmetry and comprising only N and H atoms
Alexander J. Blake Yonas Chebude Haregewine Tadesse Berhanu Wondimu 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(9):o362-o364
In the title compound [systematic name: (1Z,3Z)‐1,3‐dihydrazinylidene‐1H‐inden‐2(3H)‐one], C9H8N4O, isolated molecules possess approximate noncrystallographic C2v symmetry and their cis conformation and planarity are assisted by a pair of short intramolecular N—H...O hydrogen bonds. Each molecule is asymmetrically involved in an extensive three‐dimensional network of N—H...O and N—H...N hydrogen bonds, and the structure also exhibits weaker π–π and C=O...C interactions. The structure features an R44(12) motif consisting solely of N and H atoms and possessing crystallographic symmetry. 相似文献