Energy Transfer Processes in Tb(III)-Dibenzoylmethanate Complexes with Phosphine Oxide Ligands

Francisco A Silva Jr,Gilberto F Sá,Helenise A Nascimento,Ercules E S Teotonio,Dariston K S Pereira,Maria Cláudia F C Felinto,Wagner M Faustino,José Geraldo P Espínola,Hermi F Brito

doi:10.5935/0103-5053.20130073

Francisco A Silva Jr, Gilberto F Sá + Show 7 more

Open Access

https://doi.org/10.5935/0103-5053.20130073

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Abstract

The Tb3+-β-diketonate complexes [Tb(DBM)3L], [Tb(DBM)2(NO3)L2] and [Tb(DBM)(NO3)2(HMPA)2] (DBM = dibenzoylmethanate; L: TPPO = triphenylphosphine oxide or HMPA = hexamethylphosphine oxide) were prepared and characterized by elemental analysis (CHN), complexometric titration with EDTA and Fourier transform infrared (FTIR) spectroscopy, and the photoluminescence properties evaluated. The triplet state energies of the coordinated DBM ligands were determined using time-resolved phosphorescence spectra of analogous Gd3+ complexes. The results show that the energies increase along with the number of coordinated nitrate anions replacing the DBM ligand in the complexes. The luminescence spectra and emission lifetime measurements revealed that the ligand-to-metal energy transfer efficiency follows the same tendency. Unlike the tris-DBM complexes, bis- and mono-DBM presented high luminescence, and may act as promising candidates for preparation of the emitting layer of light converting molecular devices (LCMDs).

Highlights

Several transition metal and lanthanide b-diketonate complexes have been reported in the literature.[1,2,3,4] InEnergy Transfer Processes in Tb(III)-Dibenzoylmethanate Complexes with Phosphine Oxide Ligands J
This is probably due to the lower donor capacity and steric hindrance of TPPO when compared to HMPA, which allows coordination of more than one DBM ligand to the lanthanide ion
The coordination modes of the dibenzoylmethanate, phosphine oxide and nitrate ligands were investigated based on their characteristic Fourier transform infrared (FTIR) absorption bands (Figure S1 in the Supplementary Information (SI) section)

Summary

Introduction

Several transition metal and lanthanide b-diketonate complexes have been reported in the literature.[1,2,3,4] InEnergy Transfer Processes in Tb(III)-Dibenzoylmethanate Complexes with Phosphine Oxide Ligands J. Our group extends the investigation to the mono-, bis- and tris-DBM complexes, [Ln(DBM)3L], [Ln(DBM)2(NO3)L2)] and [Ln(DBM)(NO3)2L2)] (DBM = dibenzoylmethanate; L: TPPO = triphenylphosphine oxide or HMPA = hexamethylphosphine oxide; Ln = Tb3+ and Gd3+), and the study of the dependence of Tb3+ luminescence properties as a function of the number of coordinated β-diketonate ligands.

Results

Conclusion