Isovalent AgIII /AgIII , AgII /AgII , Mixed-Valent AgII /AgIII , and Corrolato-Based Mixed-Valency in β,β'-Linked [Bis{corrolato-silver}]n Complexes

Abstract

Mixed-valent compounds are fascinating entities that are useful as models for investigating electron-transfer reactions, and find use in a host of biologically relevant redox processes. Though the bio-relevant metal copper is well established in mixed-valent chemistry, the Ag^II /Ag^III mixed-valent combination of its higher congener in a molecular complex has rarely been reported before. This work reports the synthesis of a new β,β'-linked bis{corrolato-silver(III)} complex and its characterization in five different redox states. A combination of electrochemistry, spectroelectrochemistry, and DFT calculations point to the existence of a mixed-valent Ag^II /Ag^III and an isovalent Ag^II /Ag^II form. Additionally, characterization of the Ag^III /Ag^III form and ligand-based corrolato-centered mixed-valency is presented as well. These results thus open new avenues for bis-corrolato ligands and for mixed-valency in disilver compounds.

Keywords: EPR spectroscopy; cyclic voltammetry; mixed valency; silver corroles; spectroelectrochemistry.