Inorganic Seminar
"Complexes of Manganese (II) for Sustainable Photochemistry"
Chromophores using transition metals like Ru(II) and Ir(III) have been at the center of the inorganic photophysics scene for decades thanks to their long-lived charge-separated excited states. Due to the scarcity of these metals, it is desirable to move towards earth-abundant alternatives, such as first-row transition metals.
Recently, manganese has emerged as an attractive alternative thanks to its high abundance, low toxicity, and rich redox chemistry: It can access several oxidation states, of which +2 is the most stable. Despite its stability, Mn(II) has received limited attention because of its tendency to form high-spin complexes that cannot access charge-separated excited states. Our group’s work focuses on photoactive complexes of Mn(II) with N-donor and N-heterocyclic carbene (NHC) ligands.
The first part of this talk discusses a series of complexes we have prepared using derivatives of (E)-[(2-pyridyl)methylene](p-tolyl)amine: their photophysical properties are significantly affected by pi-stacking. We have also shown that charge-separated excited states are accessible for high-spin Mn(II) compounds. The second half of this talk focuses on air-stable, low-spin Mn(II) complexes we have synthesized using NHC ligands. These complexes have charge-separated excited states that can be accessed with visible light.