Synthesis and Anion Recognition of Acyclic Ferrocene-Based Imidazole Receptors

Abstract

The design and synthesis of artificial receptors capable of binding and sensing anions have been widely explored in the field of host-guest chemistry. Herein, a series of acyclic ferrocene-based imidazolium receptors 3a～3e were designed and synthesized. All the receptors were prepared by reactions of 1-(ferrocenylmethylene)imidazole 1 with corresponding dibromides in solvent under refluxing, followed by anion exchanges with NH 4 PF 6 . The structures of all the products were determined by IR, 1 H NMR, 13 C NMR, MS and elemental analysis. The crystal structure 3e was confirmed by X-ray crystallography, and it was clear that molecules were linked by C-H…F hydrogen bonds interactions. The interaction between these receptors and various anions was studied by electrochemical measurements and 1 H NMR spectroscopy. The receptors 3a～3e were proven to be highly selective and sensitive to F -. 1 H NMR titrations demonstrated that the receptors and anions form 1∶ 1 complex, and the receptors displayed a strong (C-H) ＋ …X -in anion recognition. Receptor 3c was the most effective receptor to bind with fluoride ion compared to the others.

Dinuclear (Ferrocenylmethyl)imidazolium Ionic Compounds with Polycyano Anions. Characterization, Migration, and Effects during Combustion

“…All 1,1′‐bis(1‐ferrocenylmethyl)‐3,3′‐alkylenediimidazolium bromides were synthesized using the synthetic procedure described in the literatures. [10a], [10b] Potassium 1,1,3,3‐tetracyanopropenide, pyridinium 1,1,2,3,3‐pentacyanopropenide, and tetraethyl ammonium 1,1,2,5,6,6‐hexacyano‐3,4‐ diazahexadienediide were synthesized as described by W. J. Middleton . [10c] 1 H and 13 C NMR spectra were performed with a Bruker Avance 400 MHz spectrometer unless indicated otherwise.…”

“…[10a], [10b] Potassium 1,1,3,3‐tetracyanopropenide, pyridinium 1,1,2,3,3‐pentacyanopropenide, and tetraethyl ammonium 1,1,2,5,6,6‐hexacyano‐3,4‐ diazahexadienediide were synthesized as described by W. J. Middleton . [10c] 1 H and 13 C NMR spectra were performed with a Bruker Avance 400 MHz spectrometer unless indicated otherwise. Elemental analyses were carried out with a Vario EL III Elemental Analyzer, Germany.…”

The first colorimetric receptor for the B4O72− anion based on nitro substituted phenanthroimidazole ferrocene derivatives

“…In recent years, a series of acyclic and trinuclear ferrocene-based imidazolium receptors noticeably improved selectivity toward the F À anion. [8][9][10] Structural characterization of other ferrocenyl imidazole derivatives showed that specic recognition properties involve the ferrocene being linked directly with the C2 of imidazole, with the C4 and C5 fused to a conjugative system. One of the receptors discovered was 2-ferrocenyl-1H-anthra [1,2-d]imidazole-6,11(5aH,11aH)-dione, which was capable of detecting [CN À ] aq as low as $0.1 ppm.…”