Isotopic Exchange Involving the Annulene Anion Radical and Its Dimerization to the Annulene Anion Radical

Article abstract of DOI:10.1021/jo00073a052

The addition of D2O to hexamethylphosphoramide solutions of the potassium salt of the <8>annulene anion radical results in the slow (days) formation of the monodeuteriated anion radical (C8H7D^1.1-).However, several days after a similar addition to the sodium salt solution, no C8H7D^1.1- is present.Instead, the anion radical of <16>annulene is found.These observations led to EPR and NMR studies, which have revealed the mechanism of each process.The mechanisms are based upon the facts that ion association is necessary for the isotope exchange reaction and the absence of ion association is required for the dimerization.Solutions of deuteriated <8>annulene anion radical, <8>annulene dianion, <16>annulene anion radical, and <16>annulene dianion can be readily generated from reduced solutions of <8>annulene for EPR, NMR, etc. studies by making use of the isotopic exchange and dimerization mentioned above.