Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Chemical Partition of the Radiative Decay Rate of Luminescence of Europium Complexes.

ABSTRACT: The spontaneous emission coefficient, Arad, a global molecular property, is one of the most important quantities related to the luminescence of complexes of lanthanide ions. In this work, by suitable algebraic transformations of the matrices involved, we introduce a partition that allows us to compute, for the first time, the individual effects of each ligand on Arad, a property of the molecule as a whole. Such a chemical partition thus opens possibilities for the comprehension of the role of each of the ligands and their interactions on the luminescence of europium coordination compounds. As an example, we applied the chemical partition to the case of repeating non-ionic ligand ternary complexes of europium(III) with DBM, TTA, and BTFA, showing that it allowed us to correctly order, in an a priori manner, the non-obvious pair combinations of non-ionic ligands that led to mixed-ligand compounds with larger values of Arad.

SUBMITTER: Lima NB

PROVIDER: S-EPMC4759827 | biostudies-other | 2016

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Publications

Chemical Partition of the Radiative Decay Rate of Luminescence of Europium Complexes.

Lima Nathalia B D NB Dutra José Diogo L JD Gonçalves Simone M C SM Freire Ricardo O RO Simas Alfredo M AM

Scientific reports 20160219

The spontaneous emission coefficient, Arad, a global molecular property, is one of the most important quantities related to the luminescence of complexes of lanthanide ions. In this work, by suitable algebraic transformations of the matrices involved, we introduce a partition that allows us to compute, for the first time, the individual effects of each ligand on Arad, a property of the molecule as a whole. Such a chemical partition thus opens possibilities for the comprehension of the role of ea ...[more]

PMID: 26892900

Similar Datasets

New Coumarin Dipicolinate Europium Complexes with a Rich Chemical Speciation and Tunable Luminescence.

Project description:Europium (III) luminescent chelates possess intrinsic photophysical properties that are extremely useful in a wide range of applications. The lack of examples of coumarin-based lanthanide complexes is mainly due to poor photo-sensitization attempts. However, with the appeal of using such a versatile scaffold as antenna, especially in the development of responsive molecular probes, it is worth the effort to research new structural motifs. In this work, we present a series of two new tris coumarin-dipicolinate europium (III) complexes, specifically tailored to be either a mono or a dual emitter, tuning their properties with a simple chemical modification. We also encountered a rich chemical speciation in solution, studied in detail by means of paramagnetic NMR and emission spectroscopy.

| S-EPMC7956443 | biostudies-literature

Europium Complexes: Luminescence Boost by a Single Efficient Antenna Ligand.

Project description:We advance the concept that a single efficient antenna ligand substituted in or added to an otherwise weakly luminescent europium complex is enough to significantly boost its luminescence. Our results, on the basis of photophysical measurements on 5 novel europium complexes and 15 known ones, point in the direction that ligand dissimilarity and ligand diversity are all concepts that clearly play a fundamental role in the luminescence of europium complexes. We show that it is important that a symmetry breaker ligand exists in the complex to enhance ligand dissimilarity and ligand diversity, all mainly affecting the nonradiative decay rate by reducing it. Because the presence of at least one antenna ligand is also obviously necessary, the optimal and the most cost-effective situation can be achieved by adding a single coordination symmetry breaker that is also an efficient antenna, such as 1-(2-thenoyl)-3,3,3-trifluoroacetone or 4,4,4-trifluoro-1-phenyl-1,3-butanedione. In such cases the quantum efficiency, η, is decidedly boosted, as can be verified by going from complex [EuCl2(TPPO)4]Cl·3H2O with η = 0% to the novel complex [EuCl2(BTFA)(TPPO)3], where TPPO stands for triphenylphosphine oxide, with η = 62%.

| S-EPMC6644999 | biostudies-literature

Microscopic insight into non-radiative decay in perovskite semiconductors from temperature-dependent luminescence blinking.

Project description:Organo-metal halide perovskites are promising solution-processed semiconductors, however, they possess diverse and largely not understood non-radiative mechanisms. Here, we resolve contributions of individual non-radiative recombination centers (quenchers) in nanocrystals of methylammonium lead iodide by studying their photoluminescence blinking caused by random switching of quenchers between active and passive states. We propose a model to describe the observed reduction of blinking upon cooling and determine energetic barriers of 0.2 to 0.8 eV for enabling the switching process, which points to ion migration as the underlying mechanism. Moreover, due to the strong influence of individual quenchers, the crystals show very individually-shaped photoluminescence enhancement upon cooling, suggesting that the high variety of activation energies of the PL enhancement reported in literature is not related to intrinsic properties but rather to the defect chemistry. Stabilizing the fluctuating quenchers in their passive states thus appears to be a promising strategy for improving the material quality.

| S-EPMC6461618 | biostudies-literature

A comprehensive strategy to boost the quantum yield of luminescence of europium complexes.

Project description:Lanthanide luminescence has many important applications in anion sensing, protein recognition, nanosized phosphorescent devices, optoelectronic devices, immunoassays, etc. Luminescent europium complexes, in particular, act as light conversion molecular devices by absorbing ultraviolet (UV) light and by emitting light in the red visible spectral region. The quantum yield of luminescence is defined as the ratio of the number of photons emitted over the number of UV photons absorbed. The higher the quantum yield of luminescence, the higher the sensitivity of the application. Here we advance a conjecture that allows the design of europium complexes with higher values of quantum yields by simply increasing the diversity of good ligands coordinated to the lanthanide ion. Indeed, for the studied cases, the percent boost obtained on the quantum yield proved to be strong: of up to 81%, accompanied by faster radiative rate constants, since the emission becomes less forbidden.

| S-EPMC3738935 | biostudies-literature

Effect of the Counterion on Circularly Polarized Luminescence of Europium(III) and Samarium(III) Complexes.

Project description:Each enantiopure europium(III) and samarium(III) nitrate and triflate complex of the ligand L, with L = N,N'-bis(2-pyridylmethylidene)-1,2-(R,R + S,S)-cyclohexanediamine ([LnL(tta)2]·NO3 and [LnL(tta)2(H2O)]·CF3SO3, where tta = 2-thenoyltrifluoroacetylacetonate) has been synthesized and characterized from a spectroscopic point of view, using a chiroptical technique such as electronic circular dichroism (ECD) and circularly polarized luminescence (CPL). In all cases, both ligands are capable of sensitizing the luminescence of both metal ions upon absorption of light around 280 and 350 nm. Despite small differences in the total luminescence (TL) and ECD spectra, the CPL activity of the complexes is strongly influenced by a concurrent effect of the solvent and counterion. This particularly applies to europium(III) complexes where the CPL spectra in acetonitrile can be described as a weighed linear combination of the CPL spectra in dichloromethane and methanol, which show nearly opposite signatures when their ligand stereochemistries are the same. This phenomenon could be related to the presence of equilibria interconverting solvated, anion-coordinated complexes and isomers differing by the relative orientation of the tta ligands. The difference between some bond lengths (M-N bonds, in particular) in the different species could be at the basis of such an unusual CPL activity.

| S-EPMC7997384 | biostudies-literature

Synthesis and Evaluation of Europium Complexes that Switch on Luminescence in Lysosomes of Living Cells.

Project description:A set of four luminescent EuIII complexes bearing an extended aryl-alkynylpyridine chromophore has been studied, showing very different pH-dependent behaviour in their absorption and emission spectral response. For two complexes with pKa values of 6.45 and 6.20 in protein-containing solution, the emission lifetime increases very significantly following protonation. By varying the gate time during signal acquisition, the 'switch-on' intensity ratio could be optimised, and enhancement factors of between 250 to 1330 were measured between pH 8 and 4. The best-behaved probe showed no significant emission dependence on the concentration of endogenous cations, reductants, and serum albumin. It was examined in live-cell imaging studies to monitor time-dependent lysosomal acidification, for which the increase in observed image brightness due to acidification was a factor of 50 in NIH-3T3 cells.

| S-EPMC7839496 | biostudies-literature

Circularly polarized luminescence in enantiopure europium and terbium complexes with modular, all-oxygen donor ligands.

Project description:The modular syntheses of three new octadentate, enantiopure ligands are reported, one with the bidentate chelating unit 2-hydroxyisophthalamide (IAM) and two with bidentate 1-hydroxy-2-pyridinone (1,2-HOPO) units. A new design principle is introduced for the chiral, non-racemic hexamines which constitute the central backbones for the presented class of ligands. The terbium(III) complex of the IAM ligand, as well as the europium(III) complexes of the 1,2-HOPO ligands, are synthesized and characterized by various techniques (NMR, UV, CD, luminescence spectroscopy). All species exhibit excellent stability and moderate to high luminescence efficiency (quantum yields Phi(Eu) = 0.05-0.08 and Phi(Tb) = 0.30-0.57) in aqueous solution at physiological pH. Special focus is put onto the properties of the complexes in regard to circularly polarized luminescence (CPL). The maximum luminescence dissymmetry factors (g(lum)) in aqueous solution are high with |g(lum)|(max) = 0.08-0.40. Together with the very favorable general properties (good stability, high quantum yields, long lifetimes), the presented lanthanide complexes can be considered as good candidates for analytical probes based on CPL in biologically relevant environments.

| S-EPMC2735592 | biostudies-literature

Unusual Magnetic Field Responsive Circularly Polarized Luminescence Probes with Highly Emissive Chiral Europium(III) Complexes.

Project description:Chirality is ubiquitous within biological systems where many of the roles and functions are still undetermined. Given this, there is a clear need to design and develop sensitive chiral optical probes that can function within a biological setting. Here we report the design and synthesis of magnetically responsive Circularly Polarized Luminescence (CPL) complexes displaying exceptional photophysical properties (quantum yield up to 31 % and |glum | up to 0.240) by introducing chiral substituents onto the macrocyclic scaffolds. Magnetic CPL responses are observed in these chiral EuIII complexes, promoting an exciting development to the field of magneto-optics. The |glum | of the 5 D0 → 7 F1 transition increases by 20 % from 0.222 (0 T) to 0.266 (1.4 T) displaying a linear relationship between the Δglum and the magnetic field strength. These EuIII complexes with magnetic CPL responses, provides potential development to be used in CPL imaging applications due to improved sensitivity and resolution.

| S-EPMC7821146 | biostudies-literature

Aggregation induced emission dynamic chiral europium(III) complexes with excellent circularly polarized luminescence and smart sensors.

Project description:The synthesis of dynamic chiral lanthanide complex emitters has always been difficult. Herein, we report three pairs of dynamic chiral EuIII complex emitters (R/S-Eu-R-1, R = Et/Me; R/S-Eu-Et-2) with aggregation-induced emission. In the molecular state, these EuIII complexes have almost no obvious emission, while in the aggregate state, they greatly enhance the EuIII emission through restriction of intramolecular rotation and restriction of intramolecular vibration. The asymmetry factor and the circularly polarized luminescence brightness are as high as 0.64 (5D0 → 7F1) and 2429 M-1cm-1 of R-Eu-Et-1, achieving a rare double improvement. R-Eu-Et-1/2 exhibit excellent sensing properties for low concentrations of CuII ions, and their detection limits are as low as 2.55 and 4.44 nM, respectively. Dynamic EuIII complexes are constructed by using chiral ligands with rotor structures or vibration units, an approach that opens a door for the construction of dynamic chiral luminescent materials.

| S-EPMC10994944 | biostudies-literature

Conservation laws, radiative decay rates, and excited state localization in organometallic complexes with strong spin-orbit coupling.

Project description:There is longstanding fundamental interest in 6-fold coordinated d(6) (t(2g)(6)) transition metal complexes such as [Ru(bpy)3](2+) and Ir(ppy)3, particularly their phosphorescence. This interest has increased with the growing realisation that many of these complexes have potential uses in applications including photovoltaics, imaging, sensing, and light-emitting diodes. In order to design new complexes with properties tailored for specific applications a detailed understanding of the low-energy excited states, particularly the lowest energy triplet state, T1, is required. Here we describe a model of pseudo-octahedral complexes based on a pseudo-angular momentum representation and show that the predictions of this model are in excellent agreement with experiment - even when the deviations from octahedral symmetry are large. This model gives a natural explanation of zero-field splitting of T1 and of the relative radiative rates of the three sublevels in terms of the conservation of time-reversal parity and total angular momentum modulo two. We show that the broad parameter regime consistent with the experimental data implies significant localization of the excited state.

| S-EPMC4485171 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data