Enhancement of anion recognition exhibited by a zinc-imidazole-based ion-pair receptor composed of C–H hydrogen- and halogen-bond donor groups. Issue 44 (30th October 2018)

• Record Type: Journal Article
• Authors: Sabater, Paula; Zapata, Fabiola; López, Bernardo; Fernández, Israel; Caballero, Antonio; Molina, Pedro
• Is Part Of: Dalton transactions. Volume 47:Issue 44(2018)
• Page Start: 15941
• Page End: 15947
• Publication Date: 2018-10-30
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt03736a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : A 2-haloimidazole derivative behaves as an anion-pair receptor in which the anion is recognised by a combination of nonconventional interactions. Abstract : A 2-haloimidazole-tetraphenylethylene ion-pair receptor1 is shown to recognise only HSO4 − anions in the presence of a cobound Zn 2+ cation guest species, which induced a remarkable increase with concomitant blue shift of the emission band of the complex [1 ·2Zn] 4+ whereas no affinity of the free receptor1 by the anions is observed. In addition, the downfield shifts observed by 1 H NMR of the Ha, Hb and Hc protons of the complex [1 ·2Zn] 4+ upon the addition of HSO4 − anions indicate their participation in the recognition event. According to DFT studies, upon chelating a Zn 2+ cation with two imidazole nitrogen atoms, receptor1 adopts a conformation ideally fitted to recognise HSO4 − through a combination of C(sp2 )–H⋯O and C(sp3 )–H⋯O hydrogen bondings, C + (sp2 )–Br⋯O halogen bonding and C(sp2 )⋯O tetrel bonding.