155341-39-2Relevant academic research and scientific papers
Alkali Metal Sensing with a Fluorescent 5,11,17,23-Tetraphenylcalixarene and the Mechanism of the Fluorescence Change
Matsumoto, Hitoshi,Shinkai, Seiji
, p. 2431 - 2434 (1994)
The fluorescence intensity of a tetraester derivative of the title compound increases markedly upon the N+-binding.Hence, this is useful as a new, convenient Na+-sensing system.The mechanism of the fluorescence increase is discussed by comparing the fluorescence properties of several reference compounds.
Di-ionizable calix[4]arene-1,3-crown-4 ligands in 1,3-alternate, cone, and partial-cone conformations: Synthesis and metal ion extractions
Yang, Yanfei,Cao, Xiaodan,Purkiss, David W.,Cannon, John F.,Bartsch, Richard A.
experimental part, p. 2233 - 2244 (2012/04/10)
Di-ionizable calix[4]arene-1,3-crown-4 compounds locked in 1,3-alternate, cone, and partial-cone conformations are synthesized for evaluation in metal ion separations. The ionizable functions include carboxylic acid and N-(X)sulfonyl carboxamide groups in which the acidity is tuned by variation of the electron-withdrawing ability of X. Similar synthetic routes were employed for preparation of the cone and 1,3-alternate ligand series. A different preparative route utilizing protection and deprotection was required to obtain the partial-cone analogues. Ligand conformations were confirmed by their proton and/or carbon NMR spectra. X-ray diffraction verified an unusual 1,2-alternate conformation in the solid-state for one synthetic intermediate. Effects of ligand conformation and ionizable group variations on competitive solvent extractions of alkali and alkaline earth metal cations from aqueous solutions into chloroform were assessed. Single species solvent extractions of Hg 2+ and Pb2+ were also performed.
Synthesis and evaluation of novel 1, 3-bridged calix[4]arene-crown ethers for selective interaction with Na+/K+ cations
Chawla, Har Mohindra,Hundal, Geeta,Kumar,Singh, Parminder
experimental part, p. 323 - 330 (2012/09/22)
Calix[4]arenes possessing electron-donating groups (OH and OR) at the lower rim when reacted with tosylated polyethers under basic conditions give the corresponding 1, 3-disubstituted calix[4]arene-crown ethers 2a-2h, in good yields. The binding properties of the synthesized 1, 3-bridged calix[4]arene-crown ethers for alkali metal cations have been investigated by atomic emission spectrometric analysis. It has been observed that recognition of sodium and potassium varies with the size of the polyether chain as well as the substituents on the free phenolics of the calix[4]arene-crown ether. The potassium/ sodium selectivity seems to be governed primarily by the size of the crown ring, relative hydrophobicity and cation-pinteraction capability to give efficiency order as 2a, 2d>2 h>2c, 2e>2b, 2f>2 g.
Metal-induced conformational change in pyrene-appended calix[4]crown-4 which is useful for metal sensing and guest tweezing
Matsumoto, Hitoshi,Shinkai, Seiji
, p. 77 - 80 (2007/10/02)
Calix[4]crown (1) bearing an ionophoric cavity on the lower rim and two pyrene groups on the upper rim was synthesized. The metal-binding to the ionophoric cavity changed the distance between two pyrene moieties, which was reflected by a large change in the monomer/excimer fluorescence intensity ratio. This phenomenon was applied to (i) fluorescence sensing of alkali metal cations and (ii) metal-controlled tweezing of a guest (trinitrobenzene). It was shown that the ionophoric cavity can accept only Li+ and Na+ (Na+ > Li+) but not at all K+.
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 (2007/10/02)
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.
