title: New Ru(II) Complex for Dual Activity: Photoinduced Ligand Release and (1)O2 Production.
abstract: The new complex [Ru(pydppn)(biq)(py)](2+) (1) undergoes both py photodissociation in CH3CN with Φ500 =0.0070(4) and (1)O2 production with ΦΔ =0.75(7) in CH3 OH from a long-lived (3) ππ* 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 Φ500 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) ππ* state necessary for dual reactivity was investigated using ultrafast and nanosecond transient absorption spectroscopy, revealing a significantly shorter (3) MLCT lifetime in 1 relative to that of the model complex 3. Due to the structural similarities between the two compounds, the lower values of Φ500 and ΦΔ compared to that of [Ru(pydppn)(bpy)(py)](2+) (2) (bpy=2,2'-bipyridine) are attributed to a competitive excited state population between the (3) LF states involved in ligand dissociation and the long-lived (3) ππ* state in 1. Complex 1 represents a model compound for dual activity that may be applied to photochemotherapy.
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Loftus
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
authors.forename: Jessica K
authors.identifier: http://orcid.org/0000-0003-2505-0955
authors.initials: JK
authors.lastname: White
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Albani
authors.affiliation: Department of Chemistry, University of Houston, Houston, Texas, 77204, USA.
authors.forename: Lars
authors.initials: L
authors.lastname: Kohler
authors.affiliation: Department of Chemistry, Wayne State University, Detroit, Michigan, 48202, USA.
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Kodanko
authors.affiliation: Department of Chemistry, University of Houston, Houston, Texas, 77204, USA.
authors.forename: Randolph P
authors.initials: RP
authors.lastname: Thummel
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas, 77845, USA. dunbar@mail.chem.tamu.edu.
authors.forename: Kim R
authors.identifier: http://orcid.org/0000-0001-5728-7805
authors.initials: KR
authors.lastname: Dunbar
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA. turro.1@osu.edu.
authors.forename: Claudia
authors.identifier: http://orcid.org/0000-0003-3202-5870
authors.initials: C
authors.lastname: Turro
mesh_terms: D004563:Electrochemistry; D008024:Ligands; D009942:Organometallic Compounds / Q000737:chemistry*; D010778:Photochemotherapy; D011725:Pyridines / Q000737:chemistry*; D011804:Quinolines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D011725:Pyridines; D011804:Quinolines; C419881:2,2'-biquinoline; D012428:Ruthenium
keywords: excited states; ligand exchange; photochemistry; ruthenium; transient absorption