Synthesis, and X-ray crystal and molecular structure of a novel macro-bicyclic ligand: crowned p-t-butyl-calix[4]arene

Abstract

Capping of p -t -butyl-calix [4]arene (1 a) with pentaethylene glycol ditoluene-p-sulphonate and ButOK in benzene leads to the first member of a new class of macrobicyclic crown compounds (2), which possess two cavities (one hydrophilic and one lypophilic) and two additional, ionizable binding sites.

Synthesis, X-ray Structure and Binding Properties of Calix[6]arene-1,4-2,5-Biscrowns

“…The first member of this family was reported by Alfieri. 2 As calixcrowns possess well preorganized structures and more rigid binding sites in comparison with calixarenes and crown ethers, they exhibited superior recognition ability toward alkali metal cations. Much attention has been paid to more sophisticated molecules: calix-biscrowns.…”

Discrimination among Octylamine Isomers by Polymeric Membrane Electrodes Based on Lipophilic Calix[6]arene Tetraester Derivatives

“…[21][22][23][24][25][26][27][28][29][30][31][32] The well-defined structure of the calixarene cavity could also be investigated for inclusion of organic guests. Actually, calix [4]crowns, penta-o-alkylated calix [5]arenes, calix [6]arene hexaesters, para-1-adamantyl calix [8]arene and homooxacalix [3]arene triether have been shown to display selectivities for primary amines. [33][34][35][36][37][38][39] Calix [6]arene has a sufficiently large cavity so that it can accommodate organic guests, whereas the calix [4]arene cavity is too small for ordinary organic guests.…”

“…Actually, calix [4]crowns, penta-o-alkylated calix [5]arenes, calix [6]arene hexaesters, para-1-adamantyl calix [8]arene and homooxacalix [3]arene triether have been shown to display selectivities for primary amines. [33][34][35][36][37][38][39] Calix [6]arene has a sufficiently large cavity so that it can accommodate organic guests, whereas the calix [4]arene cavity is too small for ordinary organic guests. In addition, the tetraester of calix [6]arene affords an excellent binding site for protonated primary amines, because the NH3 + moiety of these guests can bind strongly to the inward-directed ester carbonyl groups of the host by hydrogen bonds.…”

“…Liquid membrane type electrodes for inorganic cations, such as sodium, potassium and lithium based on the host-guest chemistry, have been developed using crown ethers and related macrocyclic hosts as well as acyclic ligands. [1][2][3][4][5][6][7][8][9][10][11] Many of these inorganic cation-selective electrodes exhibit excellent selectivity for analyte cations and are now commercially available. [12][13][14][15][16] For organic cation-ISEs based on derivatives of crown ether or natural ionophore, as reported thus far, there are not many of these ISEs that respond strongly enough to discriminate among organic guests, and the selectivities of these electrodes are mostly controlled by the lipophilicity of the guest.…”

“…[21][22][23][24][25][26][27][28][29][30][31][32] The well-defined structure of the calixarene cavity could also be investigated for inclusion of organic guests. Actually, calix [4] 33-39 Calix[6]arene has a sufficiently large cavity so that it can accommodate organic guests, whereas the calix[4]arene cavity is too small for ordinary organic guests. In addition, the tetraester of calix [6]arene affords an excellent binding site for protonated primary amines, because the NH3 + moiety of these guests can bind strongly to the inward-directed ester carbonyl groups of the host by hydrogen bonds.…”