Host–Guest Chemistry: Oxoanion Recognition Based on Combined Charge‐Assisted C−H or Halogen‐Bonding Interactions and Anion⋅⋅⋅Anion Interactions Mediated by Hydrogen Bonds. Issue 22 (9th April 2016)

• Record Type: Journal Article
• Authors: González, Lidia; Zapata, Fabiola; Caballero, Antonio; Molina, Pedro; Ramírez de Arellano, Carmen; Alkorta, Ibon; Elguero, José
• Is Part Of: Chemistry. Volume 22:Issue 22(2016)
• Page Start: 7533
• Page End: 7544
• Publication Date: 2016-04-09
• Subjects: anions -- density functional calculations -- host–guest systems -- noncovalent interactions -- receptors; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201600379
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Several bis‐triazolium‐based receptors have been synthesized and their anion‐recognition capabilities have been studied. The central chiral 1, 1′‐bi‐2‐naphthol (BINOL) core features either two aryl or ferrocenyl end‐capped side arms with central halogen‐ or hydrogen‐bonding triazolium receptors. NMR spectroscopic data indicate the simultaneous occurrence of several charge‐assisted aliphatic and heteroaromatic C−H noncovalent interactions and combinations of C−H hydrogen and halogen bonding. The receptors are able to selectively interact with HP2 O7 3−, H2 PO4 −, and SO4 2− anions, and the value of the association constant follows the sequence: HP2 O7 3− >SO4 2− >H2 PO4 − . The ferrocenyl end‐capped 7 2+ ⋅2 BF4 − receptor allows recognition and differentiation of H2 PO4 − and HP2 O7 3− anions by using different channels: H2 PO4 − is selectively detected through absorption and emission methods and HP2 O7 3− by using electrochemical techniques. Significant structural results are the observation of an anion⋅⋅⋅anion interaction in the solid state (2:2 complex, 6 2+ ⋅ [H2 P2 O7 ] 2− ), and a short C−I⋅⋅⋅O contact is observed in the structure of the complex [8 2+ ][SO4 ]0.5 [BF4 ]. Abstract : Bound together by charge : Cationic receptors with a central chiral 1, 1′‐bi‐2‐naphthol (BINOL) core show the capability to encapsulate and selectively recognize oxoanions through C−H and anion⋅⋅⋅anion hydrogen‐bonding interactions (see figure).