Sulphonamidic Groups as Electron‐Withdrawing Units in Ureido‐Based Anion Receptors: Enhanced Anion Complexation versus Deprotonation

Abstract

A sulphonamidic moiety was utilized as an electron‐withdrawing group for enhancement of anion complexation features of urea‐based receptors. A series of receptors varying in acidity of sulphonamidic and urea NH groups was synthesized and thoroughly tested. The individual complexation properties reflect deprotonation/complexation equilibrium in a given molecule as a function of the substitution. The receptors containing electron‐donating groups in conjugation to the sulphonamidic moiety showed higher association constants towards H2PO4− and carboxylate anions, while those containing electron‐withdrawing groups inclined to deprotonation of sulphonamidic NH. The deprotonation issue can be avoided by alkylation at the early step of receptor synthesis or it can be utilized for insertion of suitable groups that enable its anchoring on various substrates to form more elaborated receptor structures.

Chemoselective Electrochemical Cleavage of Sulfonimides as a Direct Way to Sulfonamides

“…The spectrum is in agreement with the literature. 40 Compounds 2, 3, and 6. A corresponding aromatic amine 1 or 5 (2.0 mmol) was dissolved in pyridine (50 mL) and stirred.…”

“…The spectral characterization is identical to that previously reported. 40 Compound 3Aa. The product 3Aa was obtained by cleavage of 3a (21.8 mg, 44.2 μmol) as a yellowish powder (11.6 mg) in 87% yield.…”

An Insight into Anion Extraction by Amphiphiles: Hydrophobic Microenvironments as a Requirement for the Extractant Selectivity

“…27 Moreover, we prepared and studied anchorable receptor moieties capable of dihydrogen phosphate recognition, by linking urea binding sites with sulfonamidic groups. 28 In the present work, we aim to anchor these moieties to a dendritic core, thus obtaining a bulky recyclable host with sulfonamide-urea binding sites. These binding sites, having a superior affinity toward dihydrogen phosphate and carboxylates, should make the resulting material suitable for liquid−liquid extraction of oxo-anions.…”

“…We previously synthesized recyclable dendritic receptors suitable for dihydrogen phosphate transport through dialysis membranes . Moreover, we prepared and studied anchorable receptor moieties capable of dihydrogen phosphate recognition, by linking urea binding sites with sulfonamidic groups . In the present work, we aim to anchor these moieties to a dendritic core, thus obtaining a bulky recyclable host with sulfonamide-urea binding sites.…”

Controlled Anchoring of (Phenylureido)sulfonamide-Based Receptor Moieties: An Impact of Binding Site Multiplication on Complexation Properties

“…We focused on the molecules carrying potent binding sites based on urea moieties conjugated to sulfonamide group. Such moiety has a superior affinity to anions with preferential 1:1 binding stoichiometry [ 24 ], even when two binding sites are present in close proximity within one molecule [ 25 ]. To induce a multiplication effect, the number of complexation sites within the receptor molecule was gradually increased, finally using their attachment to the periphery of carbosilane dendrimers.…”