Anion Binding Studies of Urea and Thiourea Functionalized Molecular Clefts

Two rationally designed 4-nitrophenyl-based molecular clefts functionalized with thiourea (L₁) and urea (L₂) have been synthesized and studied for a variety of anions by UV-Vis and colorimetric techniques in DMSO. Results from the binding studies suggest that both L₁ and L₂ bind halides showing the order: fluoride > chloride > bromide > iodide; and oxoanions showing the order: dihydrogen phosphate > hydrogen sulfate > nitrate > perchlorate. Each receptor has been shown to form a 1:1 complex with an anion via hydrogen bonding interactions, displaying distinct color change for fluoride and dihydrogen phosphate in solution. As compared to the urea-based receptor L₂, the thiourea-based receptor L₁ exhibits stronger affinity for anions due the presence of more acidic thiourea functional groups.

An overview of CO32−/HCO3− binding by aerial CO2 fixation within the self-assemblies of hydrogen-bond donor scaffolds

A comprehensive account of the F⁻/OH⁻-induced atmospheric CO₂ fixation as carbonate/bicarbonate anion(s) within the self-assemblies of artificial receptors are demonstrated in the highlight.

Effect of substitution on halide/hydrated halide binding: a case study of neutral bis-urea receptors

The impact of the substituted moiety on the binding nature of the anion with a neutral receptor through non-cooperative interaction.

Halo-phenyl based linear dipodal receptors for entrapment of anions/anionic associations within neutral non-cooperative self-assemblies

Purposeful design of rigid linear dipodal bis-urea scaffolds for the inspection of neutral self-assembly formation via coordination with anions or anionic associations.

Halo-methylphenyl substituted neutral tripodal receptors for cation-assisted encapsulation of anionic guests of varied dimensionality

Two neutral tris([(halo-methylphenyl)amino]ethyl)-urea receptors with asymmetric electronic aryl-functionalization have been developed for encapsulation of anionic guests of variable size.

Cyclic (H2O)6confined hexameric host–guest assemblies and aerial CO2fixation by electron-rich neutral urea/thiourea scaffolds

Neutral capsular assemblies of electron-rich tris-urea/thiourea receptors are formedviacyclic (H₂O)₆trapping or atmospheric CO₂fixation.

Neutral host–guest capsular associations by a homologous halophenyl-substituted organic tris-urea receptor series: solid and solution state studies

Efficient and regular construction of unimolecular fluoride-encapsulated complexes and oxyanion-bound dimeric capsular assemblies by three electron-deficient neutral tris-urea receptors is observed corroborated by solution-state analysis.