The redox behaviour and electrocatalytic proton reduction ability of the thiolate-capped triiron clusters [Fe3(CO)9(μ3-SR)(μ-H)] (1, R = iPr; 2, R = tBu) have been investigated. In CH2Cl2, both show a quasi-reversible reduction and an irreversible oxidation. The thiol substituent has a significant influence on their reduction potentials (E1/2 = −1.24 V for 1 and E1/2 = −1.40 V for 2 vs. Fc+/Fc) but less impact on oxidation potentials (E1/2 = 0.99 V for 1 and E1/2 = 0.93 V for 2 vs. Fc+/Fc). Reduction is quasi-reversible and DFT studies reveal that this is due to scission of an iron-iron bond. While the clusters are not protonated by CF3CO2H or HBF4·Et2O, they can catalyse proton reduction of these acids at their corresponding reduction potentials following an ECEC mechanism.
Subject classification (UKÄ)
- Inorganic Chemistry
- DFT studies
- Electrocatalytic proton reduction
- Triiron clusters