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. Author manuscript; available in PMC: 2020 Jul 20.
Published in final edited form as: Nat Chem. 2020 Jan 20;12(3):236–241. doi: 10.1038/s41557-019-0398-3

Fig. 4. Ring currents in topologically distinct twelve-porphyrin ring complexes.

Fig. 4

a, Molecular structure of c-P12[b12]·(T6ef)2 with two stacked bound template units. b, 1H and 19F NMR spectra of oxidised c-P12[b12]·(T6ef)2; green shading indicates the interior THSin resonance; backgrounds indicate a global aromatic (blue) or antiaromatic (orange) state. c, A circular conformation is predicted to exhibit a ring current and thus an induced magnetic moment in an external magnetic field. d, Molecular structure of c-P12[b12]·(T6f)2 figure-of-eight complex. e, 1H and 19F NMR spectra of oxidised c-P12[b12]·(T6f)2. f, In the lemniscate, the two loops induce opposite currents which cancel, and no ring current is expected. Detailed spectra are shown in Supplementary Figs. 17, 18 and 58–67. Lk, Wr and Tw are the linking number, writhe and twist that specify the topology of the loop32–34. Axy, Axz and Ayz are the net cross section areas; for c-P12[b12]·(T6f)2, Axy = 0 because the lemniscate has D2 symmetry and the areas of the two loops cancel.