Synthesis of novel podands bearing bipyridine or bipyridine-N,N'-dioxide chromophores and luminescence of their Eu3+ and Tb3+ complexes

A series of novel podand molecules bearing three or four pendant bipyridine or bipyridine-N,N'-dioxide subunits substituted at the 5,5'-positions has been synthesized and these ligands have been shown to form stable lanthanide complexes in solution: a very high luminescence quantum yield, Phi = 0.35, has been obtained for [Eu(3)](3+). This yield is the highest ever found for an isolated europium complex.