Valence Delocalization and Metal-Metal Bonding in Carbon-Bridged Mixed-Valence Iron Complexes.

ABSTRACT: The carbide ligand in the iron-molybdenum cofactor (FeMoco) in nitrogenase bridges iron atoms in different oxidation states, yet it is difficult to discern its ability to mediate magnetic exchange interactions due to the structural complexity of the cofactor. Here, we describe two mixed-valent diiron complexes with C-based ketenylidene bridging ligands, and compare the carbon bridges with the more familiar sulfur bridges. The ground state of the [Fe₂ (μ-CCO)₂ ]⁺ complex with two carbon bridges (4) is S= 1/2${{ 1/2 }}$ , and it is valence delocalized on the Mössbauer timescale with a small thermal barrier for electron hopping that stems from the low Fe-C force constant. In contrast, one-electron reduction of the [Fe₂ (μ-CCO)] complex with one carb

SUBMITTER: Fataftah MS 

PROVIDER: S-EPMC10843690 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature