Control of Fe coordination by excess Cl in alcohol solutions.

We spectroscopically investigated coordination state of Fe in methanol (MeOH) and ethanol (EtOH) solutions against Cl concentration ([Cl]). In both the system, we observed characteristic absorption bands due to the FeCl complex at high-[Cl] region. In the MeOH system, the proportion () of [FeCl] exhibits a stationary value of 0.2-0.3 in the intermediate region of 10 mM < [Cl] < 50 mM, which is interpretted in terms of [FeCl L ] ( = 1 and 2). In the EtOH system, steeply increases from 0.1 at [Cl] = 1.5 mM to 0.7 at [Cl] = 3.5 mM, indicating direct transformation from [FeL] to [FeCl]. We further found that the coordination change significantly decreases the redox potential of Fe/Fe.