On the Savéant's Concerted/Stepwise Model. The Electroreduction of Halogenated Naphthalene Derivatives as a Case Study

Abstract

The electroreduction mechanism of 1‐Br‐2‐naphtol and 1‐I‐2‐naphtol, and of two inherently chiral BINOL derivatives ([1,1′‐Binaphthalene]‐2,2′‐diol, 6,6′‐dibromo and 1,1′‐Binaphthalene,6,6′‐dibromo‐2,2′‐dimethoxy; in the following named P1 and P2, respectively), is characterized by means of an integrated electrochemical and theoretical approach. The experimental characterization is based on cyclic voltammetry measurements. The experimental results indicate that the carbon halogen bond dissociates, following the electron uptake, with the formation of an insoluble final product (electro‐polymerization). The reduction mechanism is assessed and disassembled at a molecular level by using DFT based quantum mechanical calculations. Both steady state, equilibrium, and kinetic (molecular dynamics, MD, DRC calculations) properties are calculated. A consistent picture is obtained by the comparison between experimental and theoretical results, indicating that the carbon‐halogen bond dissociates following the first electron uptake, with a stepwise mechanism.

A primer to in-situ opto- and spectro-electrochemistry

“…UV-Vis-NIR spectra can be analyzed with DFT or timedependent DFT (TD-DFT, by NWChem package) calculations to derive information such as electronic transition, steady state and HOMO-LUMO Q2 band-gap. Fontanesi characterized the electroreduction mechanism of halogenated naphthalene derivatives by integrating UV-Vis spectra and DFT calculations [37]. Stavros used boron doped diamond (BDD, Figure 4a) mesh electrode to avoid interference from a dissolved oxygen reduction signal for the study of an oxidative photocatalyst, anthraquinone-2-sulfonate (Figure 4b).…”

Chiral “doped” MOFs: an electrochemical and theoretical integrated study

“…In particular, the electrochemical behaviour was studied by performing cyclic voltammetry (CV) measurements using a solid-state electrochemical approach ( Solano et al, 2021 ; Solano et al, 2022 ). Typically, electrochemical-based CV measurements are exploited to study the electrochemical behaviour of metals and organic compounds in bulk solution ( Bonechi et al, 2021b ; Stefani et al, 2021 ; Giurlani et al, 2022b ; Bonechi et al, 2022 ), or using commercial systems of the electroplating industry ( Berretti et al, 2020 ; Mariani et al, 2022 ; Comparini et al, 2023 ). In this study we adopted a new custom-designed setup to probe the crystal electrochemical behaviour, to avoid the dissolution of the solid-state material.…”

On the Dynamics of the Carbon–Bromine Bond Dissociation in the 1-Bromo-2-Methylnaphthalene Radical Anion

“…The existence of a stepwise or concerted reaction path depends on different parameters, such as the nature of the investigated halide, the solvent and the influence of the supporting electrolyte [ 24 ]. In the scenario of aromatic halides, the stepwise reaction is, in general, the preferred dissociation pathway [ 25 ]. Based on these considerations, we propose the reaction path shown in Scheme 1 .…”