Terbium acetylacetone

A broad range of metal centers have been used for the complexation of functional ligands, including beryllium [37], zinc, transition metals such as iridium [38], and the lanthanide metals introduced by Kido [39], especially europium and terbium. Common ligands are phenanthroline (phen), bathophenanthrolin (bath), 2-phenylpyridine (ppy), acetylacetonate (acac), dibenzoylmethanate (dbm), and 11 thenoyltrifluoroacetonate (TTFA). A frequently used complex is the volatile Eu(TTFA)3(phen), 66 [40]. 

They illustrated the effects of impurities by data taken on europium tris-benzoylacetonate (EuBA), europium tris-dibenzoylmethide (EuD3), and terbium tris-acetylacetonate (TbAA) chelates. 

Acetylacetone is one of the few j8-diketone that can sensitize terbium because more extended j8-diketones usually have a triplet state lower than the emissive level of Tb +. Dibenzoylmethane (Hdbm) is an example of such an extended y3-diketone. Here, two phenyl moieties are replacing the methyl group of Hacac (Scheme 1). The deprotonation joins the two acetophenone chromophore together. The absorption of dbm then goes up to the visible spectrum. The absorption of some blue light yields a yellow solution under daylight. The triplet state is well suited for europium, which is well sensitized by dbm , provided that an additional neuttal molecule such as phenanthroline is added to complete the coordination sphere. 

---