Sensing of Antipyretic Carboxylates by Simple Chromogenic Calix[4]pyrroles

Abstract

We present a simple, two- or three-step method for the synthesis of chromogenic octamethylcalix[4]pyrrole-based (OMCP) sensors for anions. Electrophilic aromatic substitution allows for converting the pyrrole moieties of OMCP into a dye. The formation of a sensor-anion complex results in partial charge transfer and a dramatic change in color. The absorption (UV-vis) and NMR titration experiments show that the chromogenic OMCPs sense anions administered as aqueous solutions, even at high ionic strength ( approximately 0.1 M NaCl), while displaying selectivity for pyrophosphate and carboxylate anions. The experiments with polyurethane sensor films show a strong response for aqueous carboxylates, such as antipyretics naproxen approximately ibuprofen > salicylate, without being biased by bicarbonate or carboxy termini of blood plasma proteins.

Tri‐ and Pentacalix[4]pyrroles: Synthesis, Characterization and Their Use in the Extraction of Halide Salts

“…Anions play crucial roles in regulating human health [3] and are ubiquitous in biological systems. [4] In addition, anion receptors can be used as ion-selective receptors, [5] phase-transfer catalysts, and anion-selective optical sensors.…”

“…In this context, calix [4]pyrroles, which are macrocyclic compounds containing four pyrrole units connected to each other through sp 3 -hybridized carbon atoms, have emerged as molecules of particular interest, [8] because the core structure can be accessed in one synthetic step and a large number of modifications are readily conceivable. To date, simple meso-alkyl-substituted, halogenated, [10] C-rim modified, [11] photoactive and chromophore-modified, [5] strapped, [12] ditopic, [13] expanded, [14] Nconfused, [15] siloxane-functionalized, [16] and polyfunctional [17] calixpyrrole derivatives have been reported. Calix [4]pyrroles have also engendered extensive research effort because of their ability to recognize certain anionic guests (e.g., fluoride, chloride, and dihydrogen phosphate) in organic media.…”

Exploring the Dynamics of Calix[4]pyrrole: Effect of Solvent and Fluorine Substitution

“…[1][2][3][4][5][6][7][8][9][10][11] One of the most popular and versatile chemical receptors is calix [4]pyrrole (mesooctaalkylporphyrinogens; CP), a molecule first synthesized more than 100 years ago, [12] but which only recently has been investigated as chemical receptor for small anions. [13][14][15][16][17][18][19][20][21][22][23][24] Abstract: Molecular dynamics simulations show that calix [4]pyrrole (CP) and octafluorocalix [4]pyrrole (8F-CP) are extremely flexible molecules.…”

Syntheses, Structures, and Anion‐Binding Properties of Two Novel Calix[2]benzo[4]pyrroles

“…For this reason, it may be a more convenient starting material than 1 for the construction of optical anion sensors by functionalisation with appropriate chromophores. [17] Experimental Section General methods and instrumentation: Acetonitrile was distilled from CaH 2 . Pyrrole was distilled before use.…”