Fig. 1.

UV-visible difference absorption spectra obtained upon electrochemical reduction of 1⁶⁺ (solid line) and 2⁶⁺ (dashed line) at –0.50 V vs. SCE in a spectroelectrochemical thin-layer cell (5.0 × 10^–4 mol·liter^–1 acetonitrile solution at room temperature). The spectra were normalized to the intense band peaking at 392 nm for 1⁶⁺.(Inset) Detail of the spectra in the 370–405 nm region.