Electrogenerated chemiluminescence from osmium(II) polypyridine carbonyl chloride systems

The spectroscopy, electrochemistry and electrogenerated chemiluminescence (ECL) of four osmium(II) phenanthroline carbonyl chloride complexes are reported. Three of these compounds also contain diphosphine chelating ligands. ECL is generated in acetonitrile solutions with tri-n-propylamine (TPrA) as an oxidative–reductive coreactant. ECL efficiencies (ϕecl = photons emitted per redox event) between 0.011 and 0.13 were obtained in air saturated and deoxygenated solutions with Ru(bpy)32+ (bpy = 2,2′-bipyridine) as a relative standard (ϕecl = 1). The ECL intensity peaks at a potential corresponding to oxidation of both TPrA and the osmium systems, while ECL spectra (obtained using absorption filters) are similar to photoluminescence spectra, indicating that emission is from the excited states of the osmium complexes.

The spectroscopy, electrochemistry and coreactant electrogenerated chemiluminescence (ECL) of four osmium polypyridyl carbonyl chloride complexes are reported.Figure optionsDownload as PowerPoint slideHighlights
► Osmium complexes display coreactant electrogenerated chemiluminescence in acetonitrile.
► Photoluminescent efficiencies are often higher than a Ru(bpy)32+ standard, while ECL efficiencies are lower.
► The excited states of the complexes are sensitive to environmental influences.