Synthesis And Characterization Of The New Triphenylphosphine Oxide Neutral Ligands And Their Europium(Ⅲ) Complexes

One novel series of N-heterocyclic neutral ligands were synthesized. They were N-heterocyclic gropus modified triphenylphosphine oxide ligands, which were synthesized by introducing benzoxazole or benzothiazole moieties into the triphenylphosphine oxide framework. The resultant triphenylphosphine oxide derivatives have enlarged conjugation planes and improved rigidity and electronic transmission. They show good antennae effects for sensitizing Eu(III) emissions.The structure of the ligand Lx:Using five new N-heterocyclic gropus modified triphenylphosphine oxide derivatives as the neutral ligands and dibenzoylmethanate (DBM),2-thenoyltrifluoroacetonate (TTA), hexafluoroacetonate (HFAC),2-hydroxy-4-methoxybenzophenone (BP) and nitrate (NO3-) as the first ligands respectively, four series of total24new ternary europioum(III) complexes were synthesized. The photoluminescence properties of the complexes were thoroughly investigated through analyzing the triplet state energy levels of the neutral ligands, photoluminescent quantum yields and lifetimes.The above results showed that:the triplet state energy levels of the neutral ligands match well with the5D0state of Eu3+ion and can efficiently sensitize the euripum(III) emissions. The five series solid complexes exhibit intense red emission of Eu(III) ion at room temperature under the excitation of300-500nm, of which the luminescent efficiencies of TTA series complexes are among the best with the highest quantum yield up to36.4%. It is most likely to become a potential red electroluminescent material. The complexes with triphenylphosphine oxide derivatives as neutral ligands show good luminescent properties than that with TPPO as neutral ligands, suggesting that newly synthesized neutral ligand is an excellent sensitizer for europium (Ⅲ) luminescence.