Correspondence on "How Aromatic Are Molecular Nanorings? The Case of a Six‐Porphyrin Nanoring". (11th July 2022)

• Record Type: Journal Article
• Authors: Deng, Jie‐Ren; Bradley, David; Jirásek, Michael; Anderson, Harry L.; Peeks, Martin D.
• Is Part Of: Angewandte Chemie. Volume 134:Number 36(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-11
• Subjects: aromaticity -- density functional theory -- macrocycles -- porphyrins -- ring current; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202201231
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: A recent Research Article in this journal by Matito and co‐workers 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. Experimental data from NMR spectroscopy for a whole family of nanorings provide strong evidence for global ring currents. The NMR data reveal these ring currents directly, without needing analysis by density functional theory (DFT). Furthermore, DFT calculations reproduce the experimental results when a suitable functional is used. Abstract : Porphyrin nanoring template complexes provide a wealth of experimental NMR spectroscopy data, which are sensitive to global ring currents and which can be used to answer this question. Both experiment and theory confirm that nanoring cations are globally (anti)aromatic based on magnetic shielding evidence, and consistent with Hückel's rule.