The Influence of Different Ammonium Cations on the Optical Properties of Tetrakis GdIII and EuIII Complexes

Abstract

A series of tetrakis-b-diketonate Q + [Ln(b-dik) 4 ]-, where Ln = Gd III or Eu III , Q = ammonium cations and b-dik = tta (2-thenoyltrifluoracetone) or bmdm (1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione) have been synthesized and characterized. The environment surrounding the Eu III ion depends on the lateral groups of the ligand and on the alkyl chains of the counter ion Q. The shortest lifetime (τ) = 0.29 ms, and lowest quantum efficiencies (η) = 24%, were obtained for (N(C 12 H 25) 2 (CH 3) 2) + [Eu(bmdm) 4 ]-, while (N(C 4 H 9) 4) + [Eu(bmdm) 4 ]has the longest τ = 1.04 ms and η = 90%. The Judd-Ofelt intensity parameters (Ω 2 and Ω 4) strongly changes for tta series pointing to stronger ion-dipole interactions between the-CF 3 group with the ammonium cations. The agreement between the experimental results of photoluminescence and theoretical data suggests that the geometries optimized by the Sparkle model are correct. These results point to potential candidates for building up Langmuir-Blodgett (LB) luminescent films, since it is possible to maximize the intermolecular interactions and the photoluminescent properties of tetrakis Ln III complexes.

Thermochromism of Highly Luminescent Photopolymer Flexible Films Based On Eu (III) Salts Confined in Polysulfone

“…The nature of the cations in [Eu(β-diketonate) 4 ] − -based salts can have a strong influence on the structure of the anion and consequently on the optical properties of the complexes [14,15].…”

A Europium(III) Complex with an Unusual Anion–Cation Interaction: A Luminescent Molecular Thermometer for Ratiometric Temperature Sensing

“…For the [P 6,6,6,14 ][Eu(FOD) 4 ] ionic liquid, it was observed a gradual colour change from the familiar light yellow to a deep red at temperatures close to 80 °C, attributed to partial β‐diketonate decomplexation, with concomitant establishment of a strong anion‐cation interaction . Additionally, it was also reported that the cations of [Eu(β‐diketonate) 4 ] salts can have a strong influence on the structure of the anion and consequently on the optical properties of the complexes . For complex 1 , the temperature perturbation affected the coordinating ligand, lowering its excitation energy, thus shifting the excitation spectra closer to the visible region in 10 nm.…”

Об экспериментальном определении параметров интенсивности 4f-4f-переходов по спектрам излучения соединений европия (III)

“…При расчёте большинства параметров по спектрам излучения соединений Eu 3+ в в последние два десятилетия использовалась регистрация излучаемой мощности, в то время как большинство современного оборудования позволяет определять количество излучаемых фотонов в секунду [35][36][37][38][39][40][41][42]. Кроме того, все оценки параметров интенсивности, интегральных интенсивностей и центроидов получали при использовании спектров излучения, записанных в длинах волн.…”