Fig. 7. Difference absorption spectrum from before and after electrolytic one-electron reduction of Os. A CO₂-saturated DMA solution containing Os (0.5 mM) and Et₄NBF₄ (0.1 M) as an electrolyte was reduced at −1.75 V using a UV-vis OTTLE cell with a Pt mesh working electrode and Ag/AgNO₃ reference electrode.