Mixed-valence compounds are comprised of two or more linked redox centers in different formal oxidation states. Inorganic examples have been widely studied, especially in the framework of theory developed by Hush that links optically and thermally-induced electron transfer processes.
Mixed-valence compounds are among the simplest possible model systems that one can use to investigate in detail the issues relating to electronic delocalization and electron-transfer processes, which are relevant to organic electronics.
Accordingly, COPE researchers have been studying mixed-valence systems with organic redox centers using a variety of techniques including visible/near-infrared, vibrational, electron paramagnetic resonance spectroscopy, and X-ray crystallography. These studies have provided insight into issues ranging from the structural effects of hole injection into bis(triarylamine) hole-transport materials to the effect of introducing platinum centers into conjugated polymers on electron-transfer along the conjugated chain.