Anion, Cation and Ion‐Pair Recognition by Macrocyclic and Interlocked Host Systems

Electrochemical activation of halogen bonding

“…In a second case, cationic XB donors are reduced involving XB deactivation. Both switching modes have been applied to selective anion detection, an important issue in analytical chemistry [24,25].…”

“…However, when comparing the potential shift values of analogs XB (iodinated triazoliums) and HB receptors, XB proved to be equivalent or even stronger in the investigated liquid electrolytes. A tri-ferrocenylbis(iodotriazole) (Fc-3, Figure 2), conceived by the group of Molina, showed two reversible oxidation steps involving a two-electron and a one-electron transfer and proved to be remarkably selective toward oxoanions, affecting either the oxidation potential of the second ET (sulfate, acetate) or of both (dihydrogenophosphate and hydrogenopyrophosphate), whereas halides and nitrate showed no effect N,N 0 -disubstituted viologens constitute an important class of redox mediators widely applied in catalysis and the elaboration of supramolecular complexes [24]. Iodinated dicationic viologen derivatives were used as potent XB donors in the thermodynamically stable redox state.…”

Chiral Recognition of Carboxylate Anions by (R)-BINOL-Based Macrocyclic Receptors

“…Molecular recognition has been a subject of intensive study for three decades now, including research into the synthesis and application of neutral receptors able to recognize neutral molecules as well as ions [1,2]. While biological systems are able to effectively distinguish between stereoisomers of guests in water, as is demonstrated for instance by recognition of naproxen enantiomers in the human body [3], the rational design of artificial receptors capable of recognizing chiral anions still remains a great challenge.…”

Late-Stage Functionalization of (R)-BINOL-Based Diazacoronands and Their Chiral Recognition of α-Phenylethylamine Hydrochlorides

“…Since the pioneering work of Cram, the recognition, separation, and transport of chiral guests are the main topics in supramolecular chemistry . Among the reported chiral host molecules, macrocyclic ones proved to have favorable enantiodiscrimination properties as compared with their acyclic analogues . However, preparation of macrocyclic compounds, in particular those bearing a chiral scaffold attached into a macrocyclic skeleton, is often difficult due to the unfavorable entropy effect during the macrocyclization step .…”