Fe(I)-Mediated Reductive Cleavage and Coupling of CO<sub>2</sub>:  An Fe<sup>II</sup>(μ-O,μ-CO)Fe<sup>II</sup> Core

THF solutions of a new iron(I) source, [PhBP<sup>CH</sup><sub><sup>2</sup></sub><sup>Cy</sup><sub>3</sub>]Fe ([PhBP<sup>CH</sup><sub><sup>2</sup></sub><sup>Cy</sup><sub>3</sub>] = [PhBP(CH<sub>2</sub>P(CH<sub>2</sub>Cy)<sub>2</sub>)<sub>3</sub>]<sup>-</sup>), effect the reductive cleavage of CO<sub>2</sub> via O-atom transfer at ambient temperature. The dominant reaction pathway is bimetallic and leads to the formation of a structurally unprecedented diiron Fe<sup>II</sup>(μ-O)(μ-CO)Fe<sup>II</sup> core. X-ray data are also available to suggest that bimetallic reductive CO<sub>2</sub> coupling to generate oxalate occurs as a minor reaction pathway. These initial observations forecast a diverse reaction landscape between CO<sub>2</sub> and iron(I) synthons.