New Ru-II Complex for Dual Activity: Photoinduced Ligand Release and O-1(2) Production

作者：Loftus Lauren M; White Jessica K; Albani Bryan A; Kohler Lars; Kodanko Jeremy J; Thummel Randolph P; Dunbar Kim R; Turro Claudia

来源：Chemistry - A European Journal, 2016, 22(11): 3704-3708.

DOI：10.1002/chem.201504800

• excited states
• ligand exchange
• photochemistry
• ruthenium
• transient absorption

The new complex [Ru(pydppn)(biq)(py)](2+) (1) undergoes both py photodissociation in CH3CN with phi(500)=0.0070(4) and O-1(2) production with phi=0.75(7) in CH3OH from a long-lived (3)* state centered on the pydppn ligand (pydppn=3-(pyrid-2-yl)benzo[i]dipyrido[3,2-a:2,3-c]phenazine; biq = 2,2-biquinoline; py=pyridine). This represents an order of magnitude decrease in the phi(500) compared to the previously reported model compound [Ru(tpy)(biq)(py)](2+) (3) (tpy=2,2:6,2-terpyridine) that undergoes only ligand exchange. The effect on the quantum yields by the addition of a second deactivation pathway through the low-lying (3)* state necessary for dual reactivity was investigated using ultrafast and nanosecond transient absorption spectroscopy, revealing a significantly shorter (MLCT)-M-3 lifetime in 1 relative to that of the model complex 3. Due to the structural similarities between the two compounds, the lower values of phi(500) and phi compared to that of [Ru(pydppn)(bpy)(py)](2+) (2) (bpy=2,2-bipyridine) are attributed to a competitive excited state population between the (LF)-L-3 states involved in ligand dissociation and the long-lived (3)* state in 1. Complex 1 represents a model compound for dual activity that may be applied to photochemotherapy.

• 出版日期2016-3-7