Crown Ether Ditopic Receptors for Ammonium Salts with High Affinity for Amino Acid Ester Salts

Two bis crown ether receptors were synthesized and tested as host molecules for protonated forms of alkyl amines and amino acid esters. Molecular recognition studies were conducted in CH2Cl2:MeOH (92:8) by spectrophotometric UV/Vis titrations andby spectrometric 1H NMR titrations in CDCl3. The calculated binding constants are in the range 102-105 M-1. A high affinity for L-amino acid methyl ester derivatives was found. A theoretical study at the DFT level of the synthesized receptor and some analog ligands with three different ammonium ions helps to rationalize the experimentally found trends.

Ditopic receptors containing urea groups for solvent extraction of Cu(ii) salts

Ditopic receptors containing a macrocyclic cyclen unit and a urea moiety provide selective recognition of first-row divalent metal salts.

Highly effective ion-pair receptors based on 2,2-bis(aminomethyl)-propionic acid

Working in concert cation and anion binding domains of ditopic receptors based on 2,2-bis-(aminomethyl)-propionic acid allow for highly effective complexation of sodium salts of chloride, bromide and nitrate.

Design and synthesis of Tröger's base ditopic receptors: host–guest interactions, a combined theoretical and experimental study

The host–guest interaction between flexible ditopic receptors and bisammonium ion has been investigated experimentally and computationally. The conformation folding of guest bisammonium ion molecules leads to the oscillation of the host–guest interaction.

A series of ditopic receptors for succinic acid binding

Three ditopic-abiotic receptors (R1, R2 and R3) have been designed and synthesised. The receptors have been applied for the recognition of dicarboxylic acids viz. malonic, succinic, glutaric and adipic acids. Among them, succinic acid shows the highest binding efficiency to all receptors. Recognition of succinic acid is very important due to its various adverse effects on human health upon prolonged exposure.