Efficient electrogenerated chemiluminescence from osmium(ii) polypyridine systems containing tetraphenylarsine or diphenylphosphine ligands.

The spectroscopy, electrochemistry and electrogenerated chemiluminescence (ECL) of five osmium(ii) polypyridyl systems containing either phosphine or arsine chelating ligands are reported. ECL is generated in acetonitrile and mixed CH(3)CN-H(2)O (50 : 50 v/v) solutions with tri-n-propylamine (TPrA) as an oxidative-reductive coreactant. ECL efficiencies (phi(ECL) = photons emitted per redox event) between 0.15 and 8.43 are obtained using Ru(bpy)(3)(2+) (bpy = 2,2'-bipyridine) as a relative standard (phi(ECL) = 1). The ECL efficiency is dependent on both the nature of the ligands and the solvent media. The ECL spectra are identical to photoluminescence spectra indicating formation of the same excited states in both ECL and PL.