- Insight into the Alkaline Stability of N-Heterocyclic Ammonium Groups for Anion-Exchange Polyelectrolytes
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The alkaline stability of N-heterocyclic ammonium (NHA) groups is a critical topic in anion-exchange membranes (AEMs) and AEM fuel cells (AEMFCs). Here, we report a systematic study on the alkaline stability of 24 representative NHA groups at different hydration numbers (λ) at 80 °C. The results elucidate that γ-substituted NHAs containing electron-donating groups display superior alkaline stability, while electron-withdrawing substituents are detrimental to durable NHAs. Density-functional-theory calculations and experimental results suggest that nucleophilic substitution is the dominant degradation pathway in NHAs, while Hofmann elimination is the primary degradation pathway for NHA-based AEMs. Different degradation pathways determine the alkaline stability of NHAs or NHA-based AEMs. AEMFC durability (from 1 A cm?2 to 3 A cm?2) suggests that NHA-based AEMs are mainly subjected to Hofmann elimination under 1 A cm?2 current density for 1000 h, providing insights into the relationship between current density, λ value, and durability of NHA-based AEMs.
- Chen, Nanjun,Fan, Jiantao,Hu, Chuan,Jin, Yiqi,Lee, Young Moo,Li, Hui,Liu, Haijun,Wu, Bo,Xu, Shaoyi
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supporting information
p. 19272 - 19280
(2021/07/25)
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- Coumarin[4]arene: A Fluorescent Macrocycle
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The pyranone functionalization of the upper rim of resorcinarene to provide the coumarin macrocycle called "coumarin[4]arene", possessing visible fluorescence and conformationally flexible behavior suitable for molecular recognition, has been successfully synthesized and characterized.
- Kumar, Pawan,Venkatakrishnan, Parthasarathy
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supporting information
p. 1295 - 1299
(2018/03/09)
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- GROUP 8 TRANSITION METAL CATALYSTS AND METHOD FOR MAKING SAME AND PROCESS FOR USE OF SAME IN OLEFIN DISPROPORTIONATION REACTIONS
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These catalyst compounds are represented by the formula (I and VI): wherein M is a Group 8 metal; X is an anionic ligand; L is a neutral two-electron donor ligand; A is a monotopic or ditopic chelating ligand. The present invention also relates to an easy applicable catalyst synthesis and the application in different olefin metathesis processes, e.g. Reaction Injection Molding (RIM), rotational molding, vacuum infusion, vacuum forming, process for conversion of fatty acids and fatty acid esters or mixtures thereof, in -olefins, dicarboxylic acids or dicarboxylic esters, etc.
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Page/Page column 34-35; 38
(2017/12/09)
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- Synthesis and biological evaluation of N-methyl-laudanosine iodide analogues as potential SK channel blockers
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Neuronal action potentials are followed by an afterhyperpolarisation (AHP), which is mediated by small conductance Ca2+-activated K+ channels (SK channels or KCa2 channels). This AHP plays an important role in regulating neuronal act
- Graulich,Mercier,Scuvee-Moreau,Seutin,Liegeois
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p. 1201 - 1209
(2007/10/03)
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- Rearrangements of 1,6,7-Trisubstituted 2-Methyl-1,2,3,4-tetrahydroisoquinolinium 2-Methylides
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Chemical behavior of 1,6,7-trisubstituted 2-methy-1,2,3,4-tetrahydroisoquinolinium 2-methylides 4 was investigated in fluoride-ion induced desilation reaction of 1,6,7-trisubstituted 2-methyl-2-(trimethylsilyl)methyl-1,2,3,4-tetrahydroisoquinolinium iodid
- Sato, Yoshiro,Shirai, Naohiro,Machida, Yoshio,Ito, Emiko,Yasui, Takayo,et al.
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p. 6711 - 6716
(2007/10/02)
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- Synthetic Applications of Lithiation Reactions : Part XV - New Syntheses of Isochinolines and a Novel Synthesis of Tetrahydropalmatine
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New syntheses of the isoquinoline ring system, involving organometallic intermediates, are described.This is illustrated by a novel synthesis of the alkaloid, tetrahydropalmatine, in simple steps.
- Narasimhan, N. S.,Ranade, A. C.,Bhide, B. H.
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p. 439 - 440
(2007/10/02)
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