Anion-Radicals Containing a Furan Ring and Isoelectronic Species

Anion-Radicals Containing a Furan Ring and Isoelectronic Species 

Even when isolated in an argon matrix, the anion-radical from furan undergoes ring scission at a C—O bond. This is explicable in terms of extended Hiickel molecular orbital (HMO) calculations which show that 

Of other substances containing the furan ring in an otherwise hydrocarbon molecular environment, 5 forms an anion-radical on reduction with potassium. This radical has been the subject of a solution ESR and ENDOR study by Gerson and co-workers. Spin distribution, ion-pairing effects, and barriers to rotation of the phenylene groups were investigated. As implied earlier in the discussion of ECL, isobenzofurans and tetraphenylfuran also form anion-radicals.  

Anion-radicals from 2-nitrofuran derivatives liave been the subject of intensive study, particularly in the Soviet Union, on account of the wide-ranging biological activity of 2-nitrofurans and their mode of action involving perturbation of natural redox mechanisms.  

The ESR properties of the anion-radical of 2-nitrofuran (6) were recorded several years ago by Gavars et al. This group has subsequently published a series of papers concerned with the 7t-electronic structure of nitrofuran 

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