title: Electrogenerated chemiluminescence of tris(2-phenylpyridine)iridium(III) in water, acetonitrile and trifluorethanol.
abstract: The spectroscopic, electrochemical and coreactant electrogenerated chemiluminescence (ECL) properties of Ir(ppy)3 (where ppy = 2-phenylpyridine) have been obtained in aqueous buffered (KH2PO4), 50 : 50 (v/v) acetonitrile-aqueous buffered (MeCN-KH2PO4) and 30% trifluoroethanol (TFE) solutions. Tri-n-propylamine was used as the oxidative-reductive ECL coreactant. The photoluminescence (PL) efficiency (ϕem) of Ir(ppy)3 in TFE (ϕem ≈ 0.029) was slightly higher than in 50 : 50 MeCN-KH2PO4 (ϕem ≈ 0.0021) and water (ϕem ≈ 0.00016) compared to a Ru(bpy)32+ standard solution in water (Φem ≈ 0.042). PL and ECL emission spectra were nearly identical in all three solvents, with dual emission maxima at 510 and 530 nm. The similarity between the ECL and PL spectra indicate that the same excited state is probably formed in both experiments. ECL efficiencies (ϕecl) in 30% TFE solution (ϕecl = 0.0098) were higher than aqueous solution (ϕecl = 0.00092) system yet lower than a 50% MeCN-KH2PO4 solution (ϕecl = 0.0091).
authors.affiliation: Department of Chemistry, Missouri State University, Springfield, MO, USA.
authors.forename: Wesley D
authors.initials: WD
authors.lastname: Robinson
authors.forename: Mark M
authors.initials: MM
authors.lastname: Richter
mesh_terms: D000097:Acetonitriles / Q000737:chemistry*; D055664:Electrochemical Techniques; D049449:Luminescence; D009942:Organometallic Compounds / Q000032:analysis*; D014270:Trifluoroethanol / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D000097:Acetonitriles; D009942:Organometallic Compounds; C520414:tris(2-phenylpyridine)iridium(III); D014867:Water; D014270:Trifluoroethanol; C032159:acetonitrile
keywords: Coreactants; ECL; Electrogenerated Chemiluminescence; Ir(ppy)3; Trifluoroethanol