Tetrathiafulvalene dicarboxylate was oxidized in water using potassium
persulfate or a platinum anode to produce a stable cation radical. Vi
s-near-infrared spectra and ESR spectra showed that the cation radical
s aggregated to form pi-dimers and, at concentrations above 2 mM, pi-s
tacks with an optical conduction band near 2400 nm.