Skip to main content
. Author manuscript; available in PMC: 2013 Sep 3.
Published in final edited form as: Angew Chem Int Ed Engl. 2012 Aug 6;51(36):9132–9136. doi: 10.1002/anie.201203602

Figure 1.

Figure 1

UV-vis spectrum of 1 (black trace, 0.2 mM in 4:1 THF/DMF (v/v) at −90 °C) that reacted with KO2 to yield 2 (gray trace). Molar absorptivity values were calculated using a combination of UV-vis and Mössbauer experiments. Inset: X-band EPR spectrum of 2 in 4:1 THF/DMF. T = 20 K; microwave power, 2 mW, microwave frequency, 9.645 GHz, modulation amplitude, 10 G, modulation frequency, 100 Hz. Gray line is a theoretical spectrum for an S = 5/2 species with E/D = 0.08, and E/D distribution σ(E/D) = 0.03 (see text). The sharp feature marked with * arises from minor (≈0.5 % of Fe) contaminant. The high-field region is not shown as it is dominated by the intense absorption of free KO2.