Complexation and electrochemical sensing of anions by amide-substituted ferrocenyl ligands

Electrochemical recognition of anions by 1,1′-N,N′-ferrocenoylbisamino acid esters

“…However, due to the weak solubilities of ion-pairs in the acetonitrile electrolyte solution, the ion-pairs precipitate during the anodic scan and that depletes the concentration of the [ferricinium-anion] species in solution, thus the electrochemical reversibility is lost in the reverse scan. Such deviations from the reversibility have been reported previously (Reynes et al, 2001;Wopschall and Shain, 1967). An increase in the anodic peak current is likely due to precipitation of the ion-pairs onto the electrode surface that generates an auxiliary current via single electron transfer from the ion-pair to the electrode (Wopschall and Shain, 1967).…”

Electrochemical sensing of anions by redox-active receptors built on the ferrocenyl cyclam framework

“…4). This behavior is similar to that observed for a number of ferrocenebased receptor containing amide [25] or bipyridine [11] moieties and is characteristic of an EC mechanism with product adsorption [30], suggesting that the insoluble L 2þ 1 þ F À ion-pairs is adsorbed strongly onto the electrode surface. As a matter of fact, no redox signal is detected during the second scan, which shows that an insulating layer is coated onto the electrode surface from the first anodic scan.…”

“…Electrochemical and 1 H NMR titrations were conducted by adding small volumes of concentrated stock solutions of the considered anion to ligand solutions [25].…”

Redox-Dependent Conformational Switching of Diphenylacetylenes

“…However, ferrocene is also known to undergo a reversible single electron oxidation to the ferrocenium cation [39]. Studies on 1-ferrocenylcarboxamide systems show that the oxidation of Fc withdraws electron density from the amide NH bond, creating a stronger H-bond donor [40][41][42][43][44][45][46]. Thus, it is hypothesized that oxidation to Fe(III) should induce a switch in the H-bonded equilibrium toward the FcA ("oxidized", Figure 1).…”