TY - JOUR
T1 - Electrochemical redox properties of bridged and non-bridged annulenediones
AU - Gazit, Aviv
AU - Becker, James Y.
N1 - Publisher Copyright:
© 2022 The Authors. Electrochemical Science Advances published by Wiley-VCH GmbH.
PY - 2023/10/1
Y1 - 2023/10/1
N2 - The present article is fully confined to cyclic voltammetric measurements of a series of bridged and non-bridged annulenediones (quinones of large conjugated rings of aromatic character). The evaluation of their electrochemical redox properties shed light on remarkable and interesting conclusions such as aromaticity, electrostatic repulsion, disproportionation constants, and stability of their reduced charged intermediates. The results reveal that in the case of the non-bridged quinones 1–4, as the number of fused rings increases the reduction becomes gradually more difficult because the aromatic stabilization of the ‘quinone’ on conversion to aromatic ‘hydroquinone’ system decreases. However, since all studied annulenediones 5–11 possess a ‘C2’ bridge that keeps the macrocycles flat, causing better aromaticity, they are relatively easily reduced at both E1 and E2 potentials and therefore, they could be considered as quinones of aromatic systems. On the other hand, when the bridge is longer (as in 12 and 13) the macrocycles tend to bend, causing a decrease in the degree of aromaticity and as a consequence, their reduction becomes more difficult.
AB - The present article is fully confined to cyclic voltammetric measurements of a series of bridged and non-bridged annulenediones (quinones of large conjugated rings of aromatic character). The evaluation of their electrochemical redox properties shed light on remarkable and interesting conclusions such as aromaticity, electrostatic repulsion, disproportionation constants, and stability of their reduced charged intermediates. The results reveal that in the case of the non-bridged quinones 1–4, as the number of fused rings increases the reduction becomes gradually more difficult because the aromatic stabilization of the ‘quinone’ on conversion to aromatic ‘hydroquinone’ system decreases. However, since all studied annulenediones 5–11 possess a ‘C2’ bridge that keeps the macrocycles flat, causing better aromaticity, they are relatively easily reduced at both E1 and E2 potentials and therefore, they could be considered as quinones of aromatic systems. On the other hand, when the bridge is longer (as in 12 and 13) the macrocycles tend to bend, causing a decrease in the degree of aromaticity and as a consequence, their reduction becomes more difficult.
KW - bridged and non-bridged annulenediones
KW - cyclic voltammetry
KW - disproportionation constants
KW - quinones
UR - http://www.scopus.com/inward/record.url?scp=85174294946&partnerID=8YFLogxK
U2 - 10.1002/elsa.202100168
DO - 10.1002/elsa.202100168
M3 - Article
AN - SCOPUS:85174294946
SN - 2698-5977
VL - 3
JO - Electrochemical Science Advances
JF - Electrochemical Science Advances
IS - 5
M1 - e2100168
ER -