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

Molecules. 2022 Jul 15;27(14):4539. doi: 10.3390/molecules27144539.

Abstract

This paper studies the mechanism of electrochemically induced carbon-bromine dissociation in 1-Br-2-methylnaphalene in the reduction regime. In particular, the bond dissociation of the relevant radical anion is disassembled at a molecular level, exploiting quantum mechanical calculations including steady-state, equilibrium and dissociation dynamics via dynamic reaction coordinate (DRC) calculations. DRC is a molecular-dynamic-based calculation relying on an ab initio potential surface. This is to achieve a detailed picture of the dissociation process in an elementary molecular detail. From a thermodynamic point of view, all the reaction paths examined are energetically feasible. The obtained results suggest that the carbon halogen bond dissociates following the first electron uptake follow a stepwise mechanism. Indeed, the formation of the bromide anion and an organic radical occurs. The latter reacts to form a binaphthalene intrinsically chiral dimer. This paper is respectfully dedicated to Professors Anny Jutand and Christian Amatore for their outstanding contribution in the field of electrochemical catalysis and electrosynthesis.

Keywords: 1-bromo-2-methylnaphthalene; DFT; DRC; dissociation; electron affinity; molecular dynamics; potential energy surface; radical anion.

MeSH terms

  • Anions
  • Bromine* / chemistry
  • Carbon* / chemistry
  • Electrons
  • Naphthalenes

Substances

  • 1-bromo-2-methylnaphthalene
  • Anions
  • Naphthalenes
  • Carbon
  • Bromine

Grants and funding

C.F. gratefully thanks for the financial support from Dipartimento di Ingegneria “Enzo Ferrari” (DIEF), UniMORE, FARD 2021—linea di azione di tipo 3: “Materiali chirali per batterie al litio e celle a combustibile” and from Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), fondi triennali: “INSTM21MOFONTANESI”. M.I. thanks MIUR-Italy (“Progetto Dipartimenti di Eccellenza 2018–2022” allocated to the Department of Chemistry “Ugo Schiff” of the University of Firenze, Italy).