Evidence of electrochemical transduction of cation recognition by TEMPO derivatives

Abstract

This work reports the first example of electrochemical cation binding transduction via nitroxyl groups. It shows the possibility to transduce a complexation without a p-conjugated bridge between the redox and the host moieties. As expected, we confirm that the host/redox probe distance is a key point for transduction.Scheme 1 Structure of 1, 2 and 3.

Electrochemical Transduction on Self-Assembled Monolayers: Are Covalent Links Essential?

“…Similar behaviors were observed after the addition of Ca 2+ or Mg 2+ . As already observed in solution with 1-aza-18-crown-6, binding constant values of Ca 2+ , and Mg 2+ are the same order of magnitude as that observed for Ba 2+ . On the contrary, the apparent redox potential remained almost unchanged upon addition of Na + or Li + on mixed Fc/CE SAMs with several CE surface coverages.…”

“…On the basis of recent work focused on the strong influence of the spatial proximity between redox and complexant centers on the transduction efficiency in solution, 8 we have investigated the electrochemical transduction of complexation on mixed SAMs elaborated from 1-aza-18-crown-6 (CE) and ferrocene (Fc) thiol derivatives (Scheme 1). Mixed SAMs were elaborated by the successive adsorption of CE and Fc.…”

“…Mixed SAMs were elaborated by the successive adsorption of CE and Fc. Because the selectivity of 1-aza-18-crown-6 toward barium had already been established (binding constant K > 10 4 in solution), − experiments were first carried out with Ba 2+ .…”

Synthesis, physicochemical properties and antimicrobial activity of mono-/dinitroxyl amides

“…Despite the lack of π-conjugation in their saturated skeletons, various TEMPO derivatives show a clear dependence of their physicochemical properties (stemming from the presence of a radical site) on the electronic nature of C-4 substituents. 4,5 An in-depth insight into these effects is crucial for the rational design and practical utilisation of stable nitroxides 6 as prospective functional materials including radical batteries, 7 magneto-active compounds, 8 redox mediators in dye-sensitised solar cells, 9 and/or multi-responsive copolymers. 10 Moreover, there is an emerging range of medicinal applications of lowtoxic nitroxides as fMRI contrast enhancing 11 and radiation protective agents, 12 topical drugs for alopecia prevention, 13 and/or antioxidants displaying antihypertensive effects.…”