Anion–π Interactions in Cyanuric Acids: A Combined Crystallographic and Computational Study

Abstract

Several structures of pi complexes of isocyanuric acid and of several thio derivatives with anions have been computed by using high level ab initio calculations. The nature of the complexes has been studied by means of the method of molecular interaction potential with polarization (MIPp) and Bader's theory of atoms-in-molecules. These molecules form favorable complexes with anions and can be used as binding units for building receptors for the molecular recognition of anions. In several cases, the anion-pi interaction has been demonstrated experimentally by means of X-ray crystallography.

Precedent and Theory Unite in the Hypothesis of a Highly Selective Fluoride Receptor

“…[7][8][9] A recent investigation of cyanuric acid-anion bonding reaches the same conclusion. [11] To our knowledge, no such studies have yet been performed on the boroxine ring, but examination of its electrostatic potential map alongside those of s-triazine and cyanuric acid clearly indicated a substantial area of positive charge concentrated on the C 3 axis (Figure 1). The current study employs the density functional B3LYP method, [12] which is known to give acceptable agreement with noncovalent anion-p bond energies and distances calculated by the more expensive MP2 method.…”

Aromatische Ringe in chemischer und biologischer Erkennung: Energien und Strukturen

“…[301] Bis heute bleiben Wechselwirkungen mit neutralen oder nichtkoordinierten Arenen rar; manche Beispiele wurden jedoch in Kristallstrukturen von z. B. perfluorierten Arenen, [275c, 302] Cyanursäuren [303] und anderen [304] gefunden. Hay und Custelcean suchten in der CSD nach Anion-pKontakten mit Suchkriterien, die nur Treffer liefern sollten, die zur Kategorie reiner Anion-p-Wechselwirkungen zählen (Abbildung 28 b).…”

Anion-π interactions—interactions between benzo-crown ether metal cation complexes and counter ions

“…Most likely the reason is the electrondonating character of anions, which is expected to lead to repulsive interactions with aromatic clouds. Anioninteractions are energetically less favorable than their cation-counterparts because the anions have greater van der Waals radii than cations and the binding energies strongly depend upon distance [2][3][4][5][6].In the field of supramolecular chemistry, crown ethers (CE) belong to the most popular hosts since their inclusion complexes have found a vast number of practical applications [7]. The aromatic ring-containing crown ethers may have enhanced complexing properties due to the -stacking interactions.…”

“…Most likely the reason is the electrondonating character of anions, which is expected to lead to repulsive interactions with aromatic clouds. Anioninteractions are energetically less favorable than their cation-counterparts because the anions have greater van der Waals radii than cations and the binding energies strongly depend upon distance [2][3][4][5][6].…”