Photophysical properties of a series of high luminescent europium complexes with fluorinated ligands

Abstract

A series of high luminescent europium complexes have been synthesized such as Eu(TFNB)(3)phen (1) Eu(PFNP)(3)phen (2) Eu(HFNH)(3)phen (3) and Eu(PFND)(3)phen (4) which have beta-diketone ligands containing fluorinated alkyl chains with different lengths and conjugated naphthyl groups ie 44 4-trifluoro-1-(2-naphthyl)butane-1 3-dione (TFNB) 445 5 5-pentafluoro-1-(2-naphthyl)pentane-1 3-dione (PFNP) 44 5 5 66 6-heptafluoro-1-(2-naphthyl)hexane-1 3-dione (HFNH) and 445 5 6 67 7 8 8 9 9 10 10 10-pentadecafluoro-1-(2-naphthyl)decane-1,3-dione (PFND) And 10-phenanthroline (phen) is coordinated as the neutral second ligand in 1-4 The crystal structures of 1 and 2 have been studied which are typical and similar to that of 3 The results of TGA-DTA suggest that these Eu complexes have good thermal stabilities By means of absorption and (time resolved) emission spectroscopy including determination of luminescence quantum yields energy transfer dynamics and so on the following results have been obtained first these Eu complexes show characteristic pure red color photoluminescence emission with high quantum efficiencies from the central Eu(3+) ions through the excitation of the ligands secondly photophysical properties of 1 2 3 and 4 especially the lifetimes of excited states (5)D(0) of Eu(3+) ions and quantum efficiencies are influenced by the different lengths of fluorinated alkyl chains though the singlets (S(1)) and triplets (T(1)) of the fluorinated ligands are almost the same (C) 2010 Elsevier B V All rights reserved