نتایج جستجو برای: 12 crown 4 ether
تعداد نتایج: 1739084 فیلتر نتایج به سال:
The pH-profiles of the extraction of Cs(+) into four conventional (1-butyl-3-methylimidazolium hexafluorophosphate and bis[trifluoromethyl)sulphonyl]imides of 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, and 1-(2-ethylhexyl)-3- methylimidazolium) and two novel (trioctylmethylammonium salicylate and tetrahexylammonium dihexylsulfosuccinate) room temperature ionic liquids have been d...
Nitrobenzofurazan derivatives are well known for their fluorescence, whilst crown ethers complexing capacity toward cationic species. In this study, we present the synthesis and structural characterization of a new derivative containing both nitrobenzofurazan moieties ether core. The compound was obtained from dibenzo-18-crown-6 ether, which first nitrated, reduced to corresponding amine, subse...
Two procedures for the synthesis of benzo-21-crown-7 have been explored. The [1+1] macrocyclization with KBF₄ as the template was found to be more efficient than the intramolecular macrocyclization without template. Pseudorotaxanes form with secondary ammonium ions bearing at least one alkyl chain narrow enough to slip into the crown ether. Substitution on benzo-21-crown-7 or on the secondary a...
deuterating reagent ultimately becomes detached from the complex, with the net effect of one hydrogen atom being replaced with a deuterium atom. This H/D exchange process may repeat multiple times in the gas phase. Other pathways that are independent of the charge site and involve the interaction of the deuterating reagent directly with the labile hydrogen atom are typically higher in energy an...
Conformational restriction imposed upon Ru(bpy)32+ crown ether complexes by metal ion binding leads to enhanced luminescence.
Direct enantioseparation of racemic amine, amino-thiophene-2-yl-acetonitrile (TAN), on chiral crown ether stationary phase [Crownpak CR (+)] is described in this study. The elution behavior and the effect of acid additives on resolution of racemic amine, TAN, is intensely investigated. Moreover, the chiral recognition mechanism in this specific system is proposed based on computational methods ...
Abstract This work presents a potentiometric approach for the detection of two cathinone derivatives, namely mephedrone (4‐MMC) and clephedrone (4‐CMC). Contrary to neutral‐carriers (dibenzo‐18‐crown‐6‐ether calix[4]arene), cation‐exchanger (tetraphenylborate sodium) as active component ion‐selective membrane showed near‐Nernstian response (+47 mV/decade from 1.7 ⋅ 10 −6 5.6 −4 mol l −1 ) selec...
We report the synthesis of two [2]catenane-containing struts that are composed of a tetracationic cyclophane (TC(4+)) encircling a 1,5-dioxynaphthalene (DNP)-based crown ether, which bears two terphenylene arms. The TC(4+) rings comprise either 1) two bipyridinium (BIPY(2+)) units or 2) a BIPY(2+) and a diazapyrenium (DAP(2+)) unit. These degenerate and nondegenerate catenanes were reacted in t...
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