Compound 2

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Compound data: LRESI-MS

Compound data: ESI-MS

Compound data: MALDI-TOF MS

Compound data: DOSY

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

The mixture of topoisomers [Fe₆2](PF₆)₁₂ and [Fe₆3](PF₆)₁₂ (50 mg, 6.0 μmol) in acetonitrile (10 mL) was combined with 1M aqueous solution of NaOH (10 mL) and heated to 80 ºC for 15 minutes with vigorous stirring. After cooling to room temperature, distilled water (10 mL) was added to ensure the precipitation of all the organic reaction products which were then collected by filtration onto celite, washed with excess water and methanol before being dissolved in DCM. Removal of the solvent under reduced pressure afforded an impure demetalated mixture of 2 and 3 which was further purified by size-exclusion (CHCl₃+0.5%Et₃N) affording a colorless solid (12.6 mg, 2.1 μmol, 35 %). ¹H NMR (600 MHz, CDCl₃) [assignments refer to lettering shown in Supplementary Scheme 1, page 4] δ 8.60 (s, 1H, H^k), 8.28 – 8.20 (m, 2H, H^c, H^f), 8.13 (d, J = 6.3 Hz, 1H, Hⁱ), 8.10 – 8.03 (m, 2H, H^a, H^h), 7.65 – 7.56 (m, 1H, H^j), 7.32 – 7.25 (m, 4H, H^b, H^g, H^l), 6.87 – 6.70 (m, 6H, H^m, Hⁿ, H^o), 5.58 (s, 1H, H^r), 3.84 (t, J = 5.9 Hz, 2H, H^p), 2.92 – 2.78 (m, 4H, H^d, H^e), 2.46 – 2.38 (m, 2H, H^q). ¹³C NMR (151 MHz, CDCl₃) δ 158.85 (C^m-C-O), 155.48 (C^o-C-O), 154.32, 154.16, 153.97 (C^a-C-N, C^h-C-N, Cⁱ-C-N), 149.83 (Cⁿ-C-O), 149.51, 149.47 (C^c, C^f), 147.10 (C^k), 137.07 (C^b, C^g), 135.71, 135.65, 135.42 (C^b-C-C^c, C^f-C-C^g, C^j-C-C^k), 134.55 (C^j), 131.69 (C^k-C-C-C^l), 128.54 (C^r), 128.23 (C^l), 121.09 (C^m / Cⁿ / C^o), 120.69, 120.58, 120.52 (C^a, C^h, Cⁱ), 118.04, 115.70 (C^m / Cⁿ / C^o), 68.06 (C^p), 33.76 (C^d, C^e), 32.67 (C^q). LRESI-MS (in methanol with formic acid): m/z = 1939.17 [M+3H]³⁺ requires 1939.15; 1454.50 [M+4H]⁴⁺ requires 1454.62; 1164.08 [M+5H]⁵⁺ requires 1163.97; 970.17 [M+6H]⁶⁺ requires 970.14. HRESI-MS: m/z = 1163.8925 [M+5H]⁵⁺ (calcd. for C₃₈₄H₃₁₇N₃₆O₂₄, 1163.8960).