A Macrocyclic Furan with Accessible Oxidation States: Switching Between Aromatic and Antiaromatic Global Ring Currents. Issue 62 (2nd September 2022)

• Record Type: Journal Article
• Authors: Dishi, Or; Rahav, Yuval; Carmieli, Raanan; Gidron, Ori
• Is Part Of: Chemistry. Volume 28:Issue 62(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-02
• Subjects: π-conjugated macrocycles -- aromaticity -- macrocyclic compounds -- oligofurans -- organic semiconductors; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202202082
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Macrocyclic furans are predicted to switch between global aromaticity and antiaromaticity, depending on their oxidation states. However, the macrocyclic furans reported to date are stabilized by electron withdrawing groups, which result in inaccessible oxidation states. To circumvent this problem, a post‐macrocyclization approach was applied to introduce methylene‐substituted macrocyclic furans, which display an extremely low oxidation potential of −0.23 vs. Fc/Fc +, and are partially oxidized in ambient conditions. Additional oxidation to the dication results in aromaticity switching to a global 30πe − aromatic state, as indicated by the formation of a strong diatropic current observed in the 1 H NMR spectrum. NICS and ACID calculations support this trend and provide evidence for a different pathway for the global current in the neutral and dicationic states. According to these findings, macrocyclic furans can be rendered as promising p ‐type materials with stable oxidation states. Abstract : The first macrocyclic furan with accessible oxidation states was synthesized using a post‐macrocyclization approach. It exhibits low oxidation potentials, and switching between antiaromatic and aromatic global ring currents upon oxidation.