Rare earth Ibuprofen complexes: Highlighting a pharmaceutical

Abstract Complexes of Gd 3+ , Eu 3+ and Tb 3+ with the widely applied, nonsteroidal, anti-inflammatory drug Ibuprofen (“ibu”) have been prepared and characterized with respect to their photo-physical properties. The native complexes proved to be non-luminescent, but acquired very high quantum efficiencies of up to 75% with Eu 3+ on co-coordination with bidentate ligands (1,10-phenanthroline, 2,2′-bipyridine), accompanied by luminescent life times approaching 2 ms. However, due to energy back transfer to the ligand's triplet and the lack of suitable Tb 3+ receptor states, the long life times could not grant the expected high efficiencies for Tb(ibu) 3 phen, the highest value amounting to 27% only despite an accompanying decay of 1.927 ms.