Cation-Assisted Reversible Folding and Anion Binding by a Naphthalenediimide-Based Ditopic Ion-Pair Receptor

Abstract

A novel heteroditopic ion-pair receptor was synthesized by tethering two π-acidic naphthalenediimide units with a tridentate bisimine linker. Upon chelating a Zn or Cd ion with the linker, it adopts a U-conformation allowing the parallel NDI arms to sandwich charge-diffuse anions, and two such folded receptor molecules interlock with each other forming an [R3·M·R3·X] ion-pair complex. Extraction of the guest cation with a tetraazacrown ether returns the receptor to its original unfolded form.

From Heteroditopic to Multitopic Receptors for Ion‐Pair Recognition: Advances in Receptor Design and Applications

“…In one approach, Saha and co-workers exploited the relative binding affinities of ligands to reversibly bind MX 2 (M = Zn II , Cd II ; X = BF 4 À OTf -, ClO 4 À ) ion-pairs with tridentate pyridyl imine Schiff base linked naphthalenediimidebased receptor 42 (Scheme 3). [53] Satisfying the transition metal octahedral coordination requirements, two receptors complexed the metal cation guest which enabled two chargediffuse anion to be sandwiched between the naphthalenediimide arms. Exploiting the macrocyclic effect, switching was achieved by addition of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TACT) which released the free receptor.…”

Solvent-Directed Transformation of the Self-assembly and Optical Property of a Peptide-Appended Core-Substituted Naphthelenediimide and Selective Detection of Nitrite Ions in an Aqueous Medium

“…The π-conjugated organic molecules with functional diversity have attracted considerable research interest from scientists for more than a decade. − Naphthalenediimides (NDIs) belong to a special category of π-functional materials endowed with properties like molecular planarity, electron affinity, and thermal stability. Due to these advantageous properties, they have found applications in various fields like organic light-emitting diodes, solar cells, , photovoltaic devices, sensing, − bioprobes, , supramolecular chemistry, , and others. − Depending on the nature of the substituents attached at the periphery of naphthalenedianhydride (NDA), two types of NDI derivatives can be obtained: one is imide-substituted NDIs ,, and the other is core-substituted NDIs. − Core-substituted NDIs get more advantage over the imide-substituted NDIs as the substitution with one or more electron donor atoms at the core position of NDA leads to a rainbow collection of colored core-substituted NDIs with variable absorption over the entire visible range and high fluorescence quantum yield up to 0.8. The self-assembling nature of NDIs is the most important characteristic and they have the capability to form various well-defined self-organized nanostructures like a nanofiber, nanotube, nanoribbon, nanosheet, and nanocylinder with tunable properties. ,, To study the self-assembly of NDIs in different solvent systems, amino acids and a variety of synthetic peptides can be substituted at the periphery of NDI. − The usefulness of amino acids/peptides − arises not only due to their hydrogen bonding interaction among the amide (CO–NH) groups but also due to their biocompatible and biodegradable nature.…”

Lithium halide ion-pair recognition with halogen bonding and chalcogen bonding heteroditopic macrocycles

“…disposed electrical devices), [5][6][7] only o5% of lithium-ion batteries are recycled. 8 The judicious exploitation of heteroditopic molecular receptors, capable of simultaneously binding cationic and anionic species, has demonstrated enormous potential in facilitating the extraction and recovery of a range of transition- [9][10][11][12][13] and alkali-metal salts. [14][15][16][17][18] However, reports of employing this strategy towards extracting lithium salts, in particular, remain scarce.…”