Novel pH responsive luminescent poly(oxyethylene phosphate) tris(β-diketonate) europium (III) complexes

Abstract

Abstract:The paper reports on the dependence of the absorbance and luminescent intensity from pH of novel poly(oxyethylene phosphate) tris(β-diketonate) europium (III) complexes. The photophysical data obtained allow some preliminary assumptions about the nature of this phenomenon. Increase in luminescent efficiency is a consequence of enhanced efficiency of energy transfer caused by structural changes in complexes after water deprotonation. Remarkable change has been observed in photophysical properties of the polymer complexes by studying the fluorescent emission and excitation spectra and absorption recorded at various pH both in solution and in the solid state. Some of the complexes derivative of the dibenzoylmethane (DBM) show more than hundred times increase in the luminescence after alkalization. The pH value, at which the maximum luminescent efficiency appears, depends on the type of the fourth ligand. The difference between luminescent efficiency of the complexes in alkaline and neutral environment depends on the β-diketonate ligands and on polymer type as well.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

Semiconducting Polymer Encapsulated Mesoporous Silica Particles with Conjugated Europium Complexes: Toward Enhanced Luminescence under Aqueous Conditions

“…This is in line with the previous findings that the luminescence of lanthanide complex in aqueous media can be reduced by ion quenching or replacement. 18,55 Further comparison of luminescence in different biologically relevant aqueous media is shown in Figure 7b. The quenching for MSN-EuLC in PBS buffer, Dulbecco's modified Eagle's medium (DMEM) cell medium, and DMEM in the presence of 10% FBS (fetal bovine serum) was much more significant than that in pure water.…”

Discovering of the L ligand impact on luminescence enhancement of Eu(Dibenzoylmethane)3.Lx complexes employing transient absorption spectroscopy

“…These questions were raised after a recent publication,that suggests a possible application of the Eu(DBM) 3 .H 2 O complex as a chemosensor for the detection of ammonia [26] andthat provoked us to take a look at the DBM complexes again. Mirochnik [26] et alsuggest an explanation of the effect of luminescence enhancement of the polymer films containing Eu(DBM) 3 .H 2 O upon ammonia treatment, reported by us [27] almost ten years ago. The authors offerthereduction of the nonradiative pathways as explanation for luminescent intensity enhancement due to the substitution of the water molecules from the inner coordination sphere of the complex with nitrogencontaining ligand.However, our present studiesof the dependence of the Eu(DBM) 3 .H 2 O luminescent intensity in ethanol solutionon this substitution suggest something else(see below).…”

“…17904-83-5) was obtained from Sigma-Aldrich and used as obtained. Synthesis of Eu(DBM) 3 (H 2 O), Europium(III) tris(1,3diphenyl-1,3-propanedionato) monohydrate is described elsewhere [27]. The Eu(DBM) 3 (EDA) complex was obtained by adding an equimolar quantity of EDA toa hot saturated ethanolic solution of Eu(DBM) 3 (H 2 O) under continuous stirring.…”