TY - JOUR
T1 - The Effect of Hydrogenation on the Contest between Aromaticity and Antiaromaticity in Norcorrole
AU - Karadakov, Peter Borislavov
AU - Riley, Tom
N1 - © 2022 The Authors.
PY - 2023/1/18
Y1 - 2023/1/18
N2 - Magnetic shielding studies demonstrate that successive hydrogenation of NiII norcorrole (NiNc), a stable molecule combining aromatic and antiaromatic features, first weakens and then eliminates the central antiaromatic region, even though the NiNc antiaromatic “core”, a 14-membered conjugated cycle with 16 π electrons, is formally preserved throughout the H2NiNc−H8NiNc series. The differences between aromatic and non-aromatic isotropic shielding distributions and nucleus-independent chemical shift (NICS) values in these hydrogenated porphyrin analogues are highlighted by comparing the results for the members of the H2NiNc−H8NiNc series to those for the aromatic NiII porphyrin complex. The results strongly support the unexpected and counterintuitive conclusion that H8NiNc will be nonaromatic, without even a trace of antiaromaticity. Based on these findings, H8NiNc is predicted to be the most stable member of the H2NiNc−H8NiNc series.
AB - Magnetic shielding studies demonstrate that successive hydrogenation of NiII norcorrole (NiNc), a stable molecule combining aromatic and antiaromatic features, first weakens and then eliminates the central antiaromatic region, even though the NiNc antiaromatic “core”, a 14-membered conjugated cycle with 16 π electrons, is formally preserved throughout the H2NiNc−H8NiNc series. The differences between aromatic and non-aromatic isotropic shielding distributions and nucleus-independent chemical shift (NICS) values in these hydrogenated porphyrin analogues are highlighted by comparing the results for the members of the H2NiNc−H8NiNc series to those for the aromatic NiII porphyrin complex. The results strongly support the unexpected and counterintuitive conclusion that H8NiNc will be nonaromatic, without even a trace of antiaromaticity. Based on these findings, H8NiNc is predicted to be the most stable member of the H2NiNc−H8NiNc series.
U2 - 10.1002/chem.202203400
DO - 10.1002/chem.202203400
M3 - Article
SN - 0947-6539
JO - Chemistry : A European Journal
JF - Chemistry : A European Journal
M1 - e202203400
ER -