A recent Research Article published in this journal by Matito and coworkers claimed that none of the oxidation states of a butadiyne-linked six-porphyrin nanoring exhibit global aromaticity or antiaromaticity. Here we show that this conclusion is incorrect. A combination of density functional theory (DFT) calculations and experimental NMR data provides compelling evidence for global (anti)aromaticity in a variety of six-porphyrin nanorings in their 2+, 4+ and 6+ oxidation states. The strength of the predicted ring current depends on the choice of DFT functional, so it is crucial to use a functional that reproduces the experimental 1H NMR chemical shifts in these cations.
Supplementary figures and tables, and details of ring current susceptibility studies, and Cartesian coordinates.
ZIP file containing Cartesian coordinates as standard XYZ files.