Considering a Possible Role for [H-Fe₄N(CO)₁₂]^2– in Selective Electrocatalytic CO₂ Reduction to Formate by [Fe₄N(CO)₁₂]⁻

Abstract

[Fe4N(CO)12]− is a first-row transition element electrocatalyst that selectively produces C–H bonds to give formate from CO2 in water at −1.2 V vs SCE. We present a thermochemical analysis which probes the possibility that [H-Fe4N(CO)12]2– ((H-1)2–) is an intermediate in this process: we show that (H-1)2– is accessible at −1.2 V vs SCE, but if it were formed, we predict that it would generate H2. [Fe4N(CO)12]3– and (H-1)2– were interrogated spectroscopically, and the product of CO loss, [Fe4N(CO)9(μ-CO)2]3–, was synthesized and characterized. Ultimately, we demonstrate that (H-1)2– is an unlikely participant in the catalytic transformation of CO2 to formate.