Resolving ambiguity in assigning electrons to metal and ligand orbitals portends broad consequences for employing coordination complexes in modern technologies. Physicochemical behaviors of interest include spin state switching, valence tautomerism, and redox noninnocence: all of these are relevant to developing new catalysis, sensors, and magnetic/electronic devices. The canonical definitions for these phenomena are clear, but sometimes one finds real-world examples where the lines are blurred, enabling new understanding. In this vein, we have invested considerable effort to elucidate the electronic structures of Cr, V, and Fe (aromatic) diimine complexes. Examples include a doublet ground state observed in a nominally 3d<sup>3</sup> complex, and predicting Fe(II) spin-state lability by switching focus from metal-ligand bonding to interactions between ligand donor atoms. Syntheses and characterizations of these and related complexes will be described, and efforts to describe their electronic structures will be connected to computational approaches for visualizations of key interactions.

Playing “hide and seek” with electrons in first row transition metal complexes

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.