Metal centered ligand field excited states: Their roles in the design and performance of transition metal based photochemical molecular devices

Transition metal complexes are vital components in a wide range of photooptical applications; these range from targeted drug delivery to devices for the conversion of solar energy to electrical and/or stored chemical energy. Metal centered (MC) ligand field excited states play important roles in the photophysics of those complexes having partially filled d-orbitals. This review offers a broad perspective on key investigations that have characterized the chemistry and physics of MC excited states in d³ and d⁶ transition metal complexes. It will also illustrate the impact of these excited states on various photooptical applications and highlight efforts to understand, control, and tune these MC excited states in the context of such applications.