Synthesis of 4,7-bis(diphenylphosphoryl)-1,10-phenanthroline and a dinuclear EuIII complex thereof

4,7-Bis(diphenylphosphoryl)-1,10-phenanthroline (L), a new promising ligand, has been synthesized in six preparative steps, the key step having been the reaction of 4,7-dichloro-1,10-phenanthroline with Ph₂PLi. Treatment of the synthesized ligand with europium(III) (2-thenoyl)trifuoroacetonate, Eu(tta)₃, unexpectedly yields a dinuclear complex [Eu₂(tta)₄(CF₃COO)₂(L)₂], in which each Eu^III atom is N,N'-chelated by one L ligand and O-coordinated by the second L ligand.