155341-38-1Relevant academic research and scientific papers
Regioselective Synthesis of 1,2- and 1,3-Bridged Calixcrowns. What Are the Factors Controlling the Regioselectivity?
Yamamoto, Hiromasa,Sakaki, Toru,Shinkai, Seiji
, p. 469 - 472 (1994)
The product distribution in the synthesis of calixcrowns from calixarene-25,26,27,28-tetrol and 3,6-dioxaoctane-1,8-ditosylate was investigated in detail. It was shown that the 1,2- vs. 1,3-bridging regioselectivity is governed by the basicity and the metal cation of the used base. The findings enable us to regioselectively synthesize desired calixcrowns in good yields, which has been believed to be too difficult to control.
Application of nano-baskets for extraction of lanthanides
Mokhtari, Bahram,Pourabdollah, Kobra
, p. 740 - 743 (2013/03/13)
Eight proton di-ionisable diacid conformers of nano-baskets including 25,26-di(carboxymethoxy)calix[4]arene-crown- 3, -crown-4, -crown-5 and -crown-6 in the cone conformation have been synthesised and shown to extract lanthanide cations effectively. Their selectivities were greatly influenced by the acidity of the solution and the conformations of the calix-crown. The extraction loading was improved by having the p-tert-butyl-moiety in the upper rim. The scaffold bearing the crown-4 ether moiety showed the least loading, while scaffolds with crown-3- and crown-5-ether moieties had the best selectivities.
Electrochemical study of structural effects in complexation of nano-baskets: Calix[4]-1,2-crown-3,-crown-4,-crown-5,-crown-6
Mokhtari, Bahram,Pourabdollah, Kobra
, p. 1091 - 1097,7 (2020/08/31)
Eight nano-baskets of calix[4]arene-1,2-crown-3,-crown-4,-crown-5,-crown-6 were synthesized and their binding abilities towards alkali and alkaline earth metals as well as some lanthanides were studied using differential pulse voltammetry. The novelty of this study was investigation of those macrocyclic complexes by voltammetric behaviors of two acidic moieties in each scaffold during complexation of crown ether ring. The results revealed that by increasing the binding ability of macrocycle and cation, the anodic oxidation peak of carboxylic acids was decreased. Moreover, the voltammetric traces of low energy complexes did not affected by encapsulated cations in the coordination space of crown ether.
Effect of crown ring size and upper moiety on the extraction of s-block metals by ionizable calixcrown nano-baskets
Mokhtari, Bahram,Pourabdollah, Kobra
experimental part, p. 3979 - 3990 (2012/03/27)
Eight ionizable nano-baskets of cone 25,26-di(carboxymethoxy)calix[4]arene- crown-3,4,5,6 were synthesized and were verified by 1H and 13C NMR spectroscopy, IR spectroscopy and elemental analysis. The competitive solvent extractions of alkali and alkaline earth metal cations were studied using such nano-baskets. The novelty of this study is including three binding units of calixarene's bowl, crown ether's ring and electron-donor ionizable moieties in a unique scaffold to assess the binding tendency towards the cations. The objective of this work is to study the extraction efficiency, selectivity and pH1/2 of such complexes. The result of solvent extraction experiments indicated that these compounds were effective extractants of alkali and alkaline earth metal cations. Their selectivities were greatly influenced by the acidity of solution and the conformations of the calixcrown. One conformer was selective to Na+ in pH ≥ 4, while the other was highly selective to Ba2+ in pH 6 and upper. Copyright
Facile synthesis of cone p-tert-butylcalix[4]arene-crown conformers
Alekseeva, Elena A.,Basok, Stepan S.,Mazepa, Alexander V.,Gren, Andrei I.
, p. 330 - 331 (2008/03/30)
The series of p-tert-butylcalix[4]arene-crowns in the cone conformation was synthesised in high yields under conditions producing disubstituted calix[4]arenes in the presence of K2CO3 in acetonitrile; the formation of calix-bis(crown)s and doubly(calix)-doubly(crown) in these reactions was established.
