Selective Binding Affinity between Quaternary Ammonium Cations and Water-Soluble Calix[4]resorcinarene

Abstract

An amphiphilic calix[4]resorcinarene bearing four hydrophilic sulfonate sites at the upper rim and four hydrophobic n-pentyl chains at the lower rim (SR4A5) was synthesized by sulfonation of tetramethoxyresorcinarene. The molecular binding behaviors of SR4A5 with different types of organic cations, i.e., singly and doubly charged aliphatic ammonium salts and singly and doubly charged π-aromatic ammonium salts, were comprehensively investigated by means of (1)H NMR, fluorescence, and UV/vis spectroscopic titration experiments. The competitive binding titrations demonstrate that, superior to the reported p-sulfonatocalix[4]arene systems, the stability constants upon association with SR4A5 can reach up to 10(6) M(-1) order of magnitude in water, ultimately leading to better binding affinity and molecular selectivity toward dicationic guests. Significantly, UV/vis spectroscopic experiments further revealed that the specific binding behaviors of SR4A5 with bispyridinium guests can be attributed to the charge transfer interaction between electron-rich and electron-deficient aromatics upon host-guest complexation. These obtained results provide an effective strategy to realize the highly selective molecular recognition process with multiply charged macrocyclic receptors and will definitely promote the development of the field of water-soluble resorcinarene-based supramolecular assemblies.

Selective O-Alkylation of the Crown Conformer of Tetra(4-hydroxyphenyl)calix[4]resorcinarene to the Corresponding Tetraalkyl Ether

“…Varying the nature of the aldehyde substituent group facilitates the modification at the macrocyclic lower-rim system. At the upper rim, the obvious positions for chemical modification are the resorcinol hydroxyl group and the ortho position [ 18 , 19 , 20 ], the hydroxyl groups of the upper rim being the most common, which can be bridged to form extended cavities or substituted by functional groups for specific applications [ 21 ]. An interesting reagent for resorcinarene modification at the upper rim is glycidyl methacrylate (GMA), which can easily undergo a ring-opening reaction with nucleophilic reagents that contain hydroxyl, carboxyl, trysil or amine groups [ 18 , 22 , 23 ].…”

Determination of Metals and Radionuclides by Newest Functionalized Reagents in Liquid Media

“…do not affect the detection efficiency of aluminium. [35][36][37][38][39][40][41][42][43][44][45][46] and calixarenes [38-41, 43, 44, 46]) are increasingly used for the efficient and selective extraction of radionuclides and other metals. The extraction of radionuclides with water-soluble calix [4]arenes, crown ether compounds, as well as the use of solid extractants (TVEX) impregnated with functionalized calixarenes are investigated.…”

Experimental Comparative Study of Dynamic Behavior in Solution Phase of C-Tetra(phenyl)resorcin[4]arene and C-Tetra(phenyl)pyrogallol[4]arene

“…There are several applications where resorcinarenes and pyrogallolarenes have contributed to significant advances, basically due to their versatility, both in synthesis and derivatives and in their molecular structure itself. A field where they have been widely used is host-guest systems [19][20][21], since the electron-rich cavity of cone-type isomers allows different types of interactions with molecules [22] to be established, especially with tetraalkylammonium-type salts or metal cations [23,24]. This has led to different areas of applications, such as sensors [25], catalysis [26,27], heavy metal complexes for purification of water tributaries [28][29][30] and chemical separations by modification of Hight Performance Liquid Chromatography (HPLC) columns [31][32][33][34], among others.…”