Synthesis, characterization, and electrochemical properties of ferrocenylimidazolium

Anion-Binding-Induced Electrochemical Signal Transduction in Ferrocenylimidazolium: Combined Electrochemical Experimental and Theoretical Investigation

“…X-ray analysis of a single crystal of 2 was obtained via slow diffusion of diethyl ether into a saturated solution of acetone. We previously reported a single crystal structure of 1a and 1b , in which the imidazolium moieties were rotated out the plane of the Cp rings by about 37.8° and 89.4°, respectively [33]. As can be expected, receptor 2 exhibited the cisoid formation with the two ferrocenyl arms situated on the same side of the imidazolium moiety (Figure 1).…”

“…Similar to the behavior in ligands 1a – 1d [33] , cyclic voltammograms (CVs) of 2 (1 × 10 −3 mol·dm −3 ) in dry acetonitrile exhibited a pair of well-defined reversible peaks at ca. 0.26 V (vs. Ag/Ag + ).…”

“…It follows our previously reported findings that the electrostatic repulsions between the ferrocenium cation and the alkali metal cations that were hold in place by benzo-15-crown-5 agreed highly satisfactorily with the Coulomb Law, and that the observed interactions vanished when alkyl chain length was increased above 1 nm [43,44]. More recently, we published the synthetic and electrochemical details of a series of 1-ferrocene alkylmethylimidazolium cations 1a – 1d (Scheme 1), and demonstrated their anion binding electrochemical sensing properties, particularly for the F − anion [33]. The present study did not aim to target a particular guest anion or attempt to tune any electrochemical response; rather, we hoped to investigate the electrostatic interaction exerted on the binding of guest anions through a reinvestigation of the behavior of the monoferrocene imidazolium salt.…”

“…Ammonium- and guanidinium-containing hosts are important examples capable of offering strong electrostatic attractions to anionic guests [19,25,26,27,28]. In addition, receptors containing imidazolium [29,30,31,32,33,34,35,36,37] and triazolium [38,39] are able to recognize anions via a combined strong electrostatic attraction to anions and the (C–H) + ···X − type of H-bonding [25]. The charge transfer reaction of the redox center, e.g., ferrocene, can be affected in several ways by linking it with the receptor moieties, according to the type of guest anions and the linking bond [29,40,41,42].…”

Synthesis and Anion Recognition of Acyclic Ferrocene-Based Imidazole Receptors

“…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.…”