Investigating the Imidazolium–Anion Interaction through the Anion‐Templated Construction of Interpenetrated and Interlocked Assemblies

Abstract

The interaction between imidazolium cations and coordinating anions is investigated through the anion-templated assembly of interpenetrated and interlocked structures. The orientation of the imidazolium motif with respect to anion binding, and hence the hydrogen bond donor arrangement, was varied in acyclic receptors, interpenetrated assemblies, and the first mono-imidazolium interlocked systems. Their anion recognition properties and co-conformations were studied by solution-phase 1H NMR investigations, solid-state structures, molecular dynamics simulations, and density functional theory calculations. Our findings suggest that the imidazolium-anion binding interaction is dominated by electrostatics with hydrogen-bonding contributions having weak orientational dependence.

Advances in Anion Supramolecular Chemistry: From Recognition to Chemical Applications

“…Very recently, bis(triazole)pyridinium analogues of these species have been prepared, with both the rotaxane [77] and catenane [78] showing selectivity for the halides (Cl À to I À ) over dihydrogen phosphate in CDCl 3 /CD 3 OD (1:1). The pyridinium axle motifs have also been exchanged for imidazolium [118] and triazolium [119] in the construction of further rotaxanes. A rotaxane has also been synthesized where the axle component-an iodotriazolium-coordinates to the .…”

The Interaction Modes of Haloimidazolium Salts in Solution

“…Based on numerous examples of 2‐haloimidazolium‐related halogen bonding (XB) in crystal structures,– it is presumed that halogen bonding provides a major contribution to its binding affinity to Lewis bases in solution. Although other non‐covalent interactions, such as anion–π,, ion pairing and hydrogen bonding (HB) may also contribute to the overall binding strength, this has not yet been thoroughly assessed and is only rarely discussed (Figure ).…”

Dual Role of the 1,2,3‐Triazolium Ring as a Hydrogen‐Bond Donor and Anion–π Receptor in Anion‐Recognition Processes

“…Recently, it has been reported that the cis isomer of a hexapyrrolic calix[4]pyrrole binds anions in a mixed‐binding mode by a combination of hydrogen bonding and anion–π interactions, whereas the trans isomer displays only hydrogen‐bonding interactions 21. In this context, we are interested in pursuing this goal to create receptors in which selectivity does not arise from size‐ and shape matching with a particular anionic guest, but rather from the combined intrinsic anion preference of two distinct noncovalent interactions 22–24. Herein, we describe a receptor capable of anion binding by a combination of both hydrogen‐bonding and anion–π interactions with a 1,2,3‐triazolium binding site, in which one ring acts as a hydrogen‐bond receptor and the other as an anion–π receptor.…”

“…[21] In this context, we are interested in pursuing this goal to create receptors in which selectivity does not arise from size-and shapem atching with ap articular anionic guest, but rather from the combined intrinsic anion preference of two distinct noncovalent interactions. [22][23][24] Herein, we describe ar eceptor capable of anion binding by ac ombination of both hydrogen-bonding and anion-p interactions with a1 ,2,3-triazolium binding site, in which one ring acts as ah ydrogen-bond receptor and the other as an anion-p receptor. This novel dual role of the 1,2,3-triazolium ring as an anionbinding site has no precedent in the literature.…”