Retrieving aromaticity of dithiadiazuliporphyrin by oxidation: illustration by experimental and theoretical investigation

The photophysical properties of neutral, monocation radical, and dication of dithiadiazuliporphyrin have been examined with a particular focus on their aromaticity. Dithiadiazuliporphyrin exhibits significantly different characteristics depending on its oxidation state. From these features, we could conclude that the aromaticity of dithiadiazuliporphyrin is changed from nonaromatic to aromatic upon oxidation from neutral to monocation radical and dication by Br2.