Receptors For Selective Recognition Research Articles

Novel anion receptors for selective recognition of dimethyl phosphinate and carboxylate

We have designed and synthesized new anion receptors 1 and 2, which have amide NH, pyrrole NH and vinyl CH as hydrogen bond donors. These receptors are selective for dimethyl phosphinate and carboxylates. Due to electron withdrawing effect of the cyano group which is trans to the vinyl hydrogen with respect to carbon-carbon double bond, receptor 1 has higher binding constants for phosphinate and carboxylate than those of receptor 2. Modeling studies shows that cyano group polarized all three hydrogens through planar π-electron network. In addition, receptor 1 gave orange colored 1,4-addition product for cyanide.

Auto-reusable receptors for selective colorimetric recognition of fluoride

Two auto-reusable colorimetric receptors for selective recognition of fluoride in polar medium are reported.

A simple naphthalimide-based receptor for selective recognition of fluoride anion

Synthesis of a simple fluorescent naphthalimide based receptor 4-aminobenzyl-N-methyl-1,8naphthalimide 3 was carried out as a selective fluoride ion sensor. In acetonitrile, interaction of 3 with different anions such as, AcO – , F – , Cl – , Br – , I – , and SCN – revealed significant fluorescence quenching only with the F – anion. In the presence of the fluoride anion, the color of the solution changed from a fluorescent green to violet and this was visible to the naked eye. The probable mode of sensing mechanism by photo-induced electron transfer (PET) reaction is attributed to deprotonation of acidic NH proton in the presence of fluoride which was confirmed by change in optical properties intramolecular charge transfer (ICT) and 1 H NMR spectral data analysis. The Job’s plot analysis displayed a 1:1 stoichiometry for interaction between 3 and F – . The extent of fluorescence quenching was estimated by Stern-Volmer plot.

ChemInform Abstract: Recognition and Separation of Sulfate Anions

AbstractReview: about 100 refs.

Neutral cryptand-like cyclic peptide–thiourea receptors for selective recognition of sulphate anions in aqueous solvents

The synthesis and anion complexation properties of two hybrid cyclic peptide–thiourea cryptands have been studied. Receptors encapsulate sulphate via nine hydrogen bonds and show selectivity for this anion in solvent mixtures containing up to 20% H2O/deuterodimethyl sulphoxide. In this solvent mixture, chloride, bromide and acetate are encapsulated via six hydrogen bonds and with lower affinity than sulphate.

Polymethylene-bridged Cystine–Glycine-containing Cyclopeptides as Hydrogen-bonding Electroneutral Anion Receptors: Design, Synthesis, and Halide Ion Recognition

Two conformationally constrained polymethylene-bridged cystine–glycine-based cyclopeptides (3 and 5) were synthesized as hydrogen-bonding electroneutral anion receptors by the conventional solution method. Both solution conformation and NMR titration studies showed that cyclopeptide 3 was an efficient receptor for selective recognition of halide ions, whereas cyclopeptide 5 failed to bind any halide ion.