477248-66-1Relevant academic research and scientific papers
Calix[4]arene-assisted KOH-catalyzed synthesis of O,O-dialkyl-Se-aryl phosphoroselenoates
Chen, Sihai,Chen, Jinyang,Xu, Xinhua,He, Yunhua,Yi, Rongnan,Qiu, Renhua
, p. 123 - 127 (2016)
A convenient and efficient method for the synthesis of O,O-dialkyl-Se-aryl phosphoroselenoates is described via a one pot reaction of diaryl diselenide and O,O-dialkylphosphonate catalyzed by KOH assisted by a co-catalyst of calix[4]arene 3. The calix[4]a
Effect of steric crowding on ion selectivity for calix-crown hybrid ionophores: Experimental, molecular modeling and crystallographic studies
Patra, Subrata,Maity, Debdeep,Sen, Anik,Suresh,Ganguly, Bishwajit,Paul, Parimal
scheme or table, p. 2796 - 2805 (2011/02/18)
A number of calix[4]arene-azacrowns with variation in ring size and substituents at the upper and lower rims have been synthesized to investigate the effect of steric crowding towards ion selectivity. The structural elucidation of these ionophores has been carried out mainly by 1H NMR and ES-MS in solution and by single crystal X-ray study in the solid state. Interaction of these ionophores with a large number of cations has been investigated by NMR studies. The ionophore with tert-butyl at the upper rim (3) exhibits selectivity towards Na+ only whereas an ionophore of the same size but without tert-butyl at the upper rim (1) shows selectivity towards both Na+ and K+. An ionophore of the same size but with three tosyl substituents at the lower rim (4) exhibits no complexation with any cation. The ionophore with the larger crown ring and without tert-butyl at the upper rim (2) exhibits complexation with K+, Rb+, Ba 2+ and weak interaction with Na+. Binding constants with these metal ions have been determined by NMR titration. Molecular modeling studies performed by a molecular mechanics force field (MMFF94) using the Monte Carlo search method and DFT calculations predicted the observed higher selectivity for sterically crowded receptor. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Synthesis and metal ion complexation studies of proton-ionizable calix[4]azacrown ethers in the 1,3-alternate conformation
Kim, Jong Seung,Shon, Ok Jae,Ko, Jong Won,Cho, Moon Hwan,Yu, Ill Yong,Vicens, Jacques
, p. 2386 - 2392 (2007/10/03)
A series of novel N-chromogenic calix[4]arene azacrown ethers were synthesized as selective extractants of potassium ion. 1,3-Alternate calix[4]arene azacrown ethers were prepared by reacting 25,27-dipropyloxy- 26,28-bis(5-chloro-3-oxapentyloxy) calix[4]arenes with p-toluenesulfonamide in the presence of potassium carbonate. The coupling reaction of calix[4]arene azacrown ether with 2-hydroxy-5-nitrobenzyl bromide in the presence of triethylamine in THF gave the chromogenic calix[4]arene azacrown ether in moderate yield. These compounds show high potassium selectivity over other metal ions as shown by two-phase extraction, bulk liquid membrane, and 1H NMR studies on a ligand-metal complex. It is assumed that the OH of the chromogenic group attached on nitrogen can assist the complexation by encapsulation of the metal.
