Sensitized Eu(III) Luminescence by Energy Transfer from the Cu(I) Antenna Chromophore

Abstract

Refluxing of 5,6-diamino-1,10-phenanthroline and 2-(diphenylphosphino)benzaldehyde in air led to the formation of a new bridging ligand, 2-(2-diphenylphosphinoyl)phenyl-1H-imidazo[4,5–f][1,10]-phenanthroline (dpipH). Then, two mononuclear phosphorescent Cu(I) complexes, [Cu(dpipH)(POP)]ClO4 (1) and [Cu(dpipH)(xantphos)]ClO4 (2), as well as two trinuclear Cu(I)-Eu(III) 3d-4f complexes [Cu2Eu(μ-dpipH)2(POP)2(tta)2](ClO4)3 (3) and [Cu2Eu(μ-dpipH)2(xantphos)2(tta)2](ClO4)3 (4), were obtained through self-assembly, where POP, xantphos and tta− denote bis[(2-diphenylphosphino)phenyl] ether, 9,9-dimethyl-4,5-bis(diphenylphosphino)-9H-xanthene and 2-thenoyltrifluoroacetone anion, respectively. The sensitized Eu(III) luminescence was successfully achieved by energy transfer from the Cu(I) antenna chromophores to the Eu(III) centers.