EPR spectra of dialkyl azulenedicarboxylate radical anions

What is it about?

Selected dialkyl azulenedicarboxylates were prepared by carbo-bromination of alkyl azulenemonocarboxylates and subsequent alcoholysis or by alkoxycarbonylcarbene insertion of ethyl indane-2-carboxylate. The electrochemical behavior of the diesters was studied by means of differential pulse polarography and cyclovoltammetry. In-situ electroreduction of the azulenedicarboxylic esters led to the corresponding radical anions, the EPR spectra of which were recorded. For certain radical anions a rearrangement under migration of the functional group from the 5- into the 6-position was observed. The spin density distribution in these non-alternant π-electron systems as determined from the proton hyperfine structure (hfs) coupling constants was compared with the results of MO calculations and discussed with respect to the influence of substituents.

Featured Image