Shift Reagent Research Articles

Enantiomeric NMR signal separation behavior and mechanism of samarium(III) and neodymium(III) complexes with (S,S)-ethylenediamine-N,N'-disuccinate.

Enantiomeric 1 H and 13 C NMR signal separation behaviors of various α-amino acids and DL-tartarate were investigated by using the samarium(III) and neodymium(III) complexes with (S,S)-ethylenediamine-N,N'-disuccinate as chiral shift reagents. A relatively smaller concentration ratio of the lanthanide(III) complex to substrates was suitable for the neodymium(III) complex compared with the samarium(III) one, striking a balance between relatively greater signal separation and broadening. To clarify the difference in the signal separation behavior, the chemical shifts of β-protons for fully bound D- and L-alanine (δb (D) and δb (L)) and their adduct formation constants (Ks) were obtained for both metal complexes. Preference for D-alanine was similarly observed for both complexes, while it was revealed that the difference between the δb (D) and δb (L) values is the significant factor to determine the enantiomeric signal separation. The neodymium(III) and samarium(III) complexes can be used complementarily for higher and smaller concentration ranges of substrates, respectively, because the neodymium(III) complex gives the larger difference between the δb (D) and δb (L) values with greater signal broadening compared to the samarium(III) complex.

Attracting Enantiomers: Chiral Analytes That Are Simultaneously Shift Reagents Allow Rapid Screening of Enantiomeric Ratios by NMR Spectroscopy.

The rapid and direct determination of enantiomeric ratios is of increasing interest due to the significantly reduced effort compared to chromatographic methods and the large number of analytes, for instance in enantioselective catalysis. Current strategies include colorimetric assays, (a)chiral solvating reagents for NMR spectroscopy and metal complexes for CD sensing. We report the determination of enantiomeric ratios based on the self-induced diastereomeric anisochronism (SIDA) effect. Alanine derivatives that represent chiral products of enantioselective catalysis, such as the well-established hydrogenation of dehydroamino acids, were investigated. The SIDA effect was significantly enhanced by attachment of 3,5-dinitrobenzoyl π-π interactions sites. This simple modification enabled simultaneous determination of enantiomeric ratios and conversions by NMR spectroscopy.

Consistent Chiral Kinetic Theory in Weyl Materials: Chiral Magnetic Plasmons.

We argue that the correct definition of the electric current in the chiral kinetic theory for Weyl materials should include the Chern-Simons contribution that makes the theory consistent with the local conservation of the electric charge in electromagnetic and strain-induced pseudoelectromagnetic fields. By making use of such a kinetic theory, we study the plasma frequencies of collective modes in Weyl materials in constant magnetic and pseudomagnetic fields, taking into account the effects of dynamical electromagnetism. We show that the collective modes are chiral plasmons. While the plasma frequency of the longitudinal collective mode coincides with the Langmuir one, this mode is unusual because it is characterized not only by oscillations of the electric current density, but also by oscillations of the chiral current density. The latter are triggered by a dynamical version of the chiral electric separation effect. We also find that the plasma frequencies of the transverse modes split up in a magnetic field. This finding suggests an efficient means of extracting the chiral shift parameter from the measurement of the plasma frequencies in Weyl materials.

Pseudomagnetic helicons

The existence of pseudomagnetic helicons is predicted for strained Dirac and Weyl materials. The corresponding collective modes are reminiscent of the usual helicons in metals in strong magnetic fields but can exist even without a magnetic field due to a strain-induced background pseudomagnetic field. The properties of both pseudomagnetic and magnetic helicons are investigated in Weyl matter using the formalism of the consistent chiral kinetic theory. It is argued that the helicon dispersion relations are affected by the electric and chiral chemical potentials, the chiral shift, and the energy separation between the Weyl nodes. The effects of multiple pairs of Weyl nodes are also discussed. A simple setup for experimental detection of pseudomagnetic helicons is proposed.

Chiral magnetic plasmons in anomalous relativistic matter

The chiral plasmon modes of relativistic matter in background magnetic and strain-induced pseudomagnetic fields are studied in detail using the consistent chiral kinetic theory. The results reveal a number of anomalous features of these chiral magnetic and pseudomagnetic plasmons that could be used to identify them in experiment. In a system with nonzero electric (chiral) chemical potential, the background magnetic (pseudomagnetic) fields not only modify the values of the plasmon frequencies in the long-wavelength limit, but also affect the qualitative dependence on the wave vector. Similar modifications can be also induced by the chiral shift parameter in Weyl materials. Interestingly, even in the absence of the chiral shift and external fields, the chiral chemical potential alone leads to a splitting of plasmon energies at linear order in the wave vector.

1H NMR Shows Slow Phospholipid Flip-Flop in Gel and Fluid Bilayers.

We measured the transbilayer diffusion of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in large unilamellar vesicles, in both the gel (Lβ′) and fluid (Lα) phases. The choline resonance of headgroup-protiated DPPC exchanged into the outer leaflet of headgroup-deuterated DPPC-d13 vesicles was monitored using 1H NMR spectroscopy, coupled with the addition of a paramagnetic shift reagent. This allowed us to distinguish between the inner and outer bilayer leaflet of DPPC, to determine the flip-flop rate as a function of temperature. Flip-flop of fluid-phase DPPC exhibited Arrhenius kinetics, from which we determined an activation energy of 122 kJ mol–1. In gel-phase DPPC vesicles, flip-flop was not observed over the course of 250 h. Our findings are in contrast to previous studies of solid-supported bilayers, where the reported DPPC translocation rates are at least several orders of magnitude faster than those in vesicles at corresponding temperatures. We reconcile these differences by proposing a defect-mediated acceleration of lipid translocation in supported bilayers, where long-lived, submicron-sized holes resulting from incomplete surface coverage are the sites of rapid transbilayer movement.

Bilayer Defects Facilitate DPPC Flip-Flop

We measured the flip-flop rate of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in large unilamellar vesicles (LUVs) as a function of temperature. The transbilayer distribution of headgroup-protiated DPPC exchanged into the outer leaflet of headgroup-deuterated DPPC vesicles was monitored using 1H NMR spectroscopy coupled with the addition of a paramagnetic shift reagent, which allowed us to distinguish between inner and outer leaflet lipids. After careful determination of structure and thermotropic behavior of this system, we determined the fluid-phase flip-flop activation energy Ea to be 123 kJ/mol. This is the first report of probe-free fluid phase flip-flop kinetics for DPPC in freely floating vesicles. No flip-flop was observed over the course of 6 days when DPPC was incubated below the main transition temperature, and consequently gel phase thermodynamic values could not be determined in LUVs. This result is in contrast with previous studies using supported bilayers that reported fast flip-flop in the gel phase. To further investigate this discrepancy, we measured DPPC LUVs incubated within the main transition temperature, and found accelerated flip-flop (i.e., faster rates than were found just above the main transition temperature). We conclude that bilayer defects such as gel/fluid domain boundaries accelerate lipid flip-flop. We speculate that sample environment and measurement conditions that can alter the physical properties of bilayers have contributed to flip-flop discrepancies in literature.

Imaging Extracellular Lactate In Vitro and In Vivo Using CEST MRI and a Paramagnetic Shift Reagent.

Overproduction of lactate is a hallmark of cancer, yet a method to quantitatively measure lactate production by cancer cells is not straight-forward. Chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) can potentially be used to image lactate but the small difference in chemical shift of the lactate -OH proton and water proton resonances make it challenging. Like other spectroscopic methods, CEST MRI cannot discriminate intracellular lactate from extracellular lactate. Herein, we demonstrate a relatively simple way to shift the lactate -OH proton resonance far away from water by addition of the paramagnetic shift reagent, EuDO3A, while retaining the CEST properties of lactate itself. The potential of the method was demonstrated by imaging extracellular lactate excreted from lung cancer cells in tissue culture without interference from other components in the culture media and by imaging excess lactate excreted into the bladder of a mouse.

Simple, efficient and economical methods for isolation and estimation of novel isoflavone using RP-HPLC

The study was undertaken to develop a simplified procedure for the isolation of bioactive isoflavone from Iris kashmiriana, using a direct method of isolation, avoiding the use of chromatographic techniques. The compound was isolated by commercially viable procedure. The extraction of powdered drug (500g) was done with petroleum ether (60–80) using a Soxhlet apparatus (24h run). The petroleum ether extract (gums and resins 2.13g) was obtained and the marc (400g) was subjected to extraction with 95% methanol using a Soxhlet apparatus (24h run). The methanolic extract (5 g) was subjected to successive fractionation with toluene, chloroform and ethyl acetate and n- butanol. On the basis of phytochemical analysis, the glycoside was present in n- butanol fraction. The n-butanol fraction (1.5g) was taken in dried methanol, passed through activated animal charcoal and subjected to acid hydrolysis. The isoflavone (250mg), was obtained after the usual process of separation. The purity of the compound was checked by analyzing TLC (Thin Layer chromatography) and melting point. Further, the chemical method was used to characterize the compound by shift reagents using UV spectroscopy. The quantitative estimation of isoflavone was done using RP-HPLC and was found to be 98.9% pure.•The “previously undescribed” isoflavone was isolated by modifying approach of solvent/solvent extraction, fractionation and acid hydrolysis.•The spectroscopic characterization was equaly done by IR, 1HNMR, 13CNMR, Mass spectrometry.•98.9% purity was achieved using RP-HPLC with simple solvent (Methanol and Water 55: 45).

Phytochemical and genotoxicity studies of Citrus reticulata aerial part in mice

Background and objectives The genus Citrus (family Rutaceae) is known to contain many bioactive compounds like flavonoids that protect mice against genotoxicity because of their antioxidant and free radical scavenging properties. The aim of this study was to investigate the phytochemical constituents and the protective effect of the ethanolic extract of the aerial part of Citrus reticulata cultivated in Saudi Arabia against genotoxicity induced by benzo(a)pyrene (BaP) in mice. Materials and methods The major constituents from of the aerial part of C. reticulata were isolated using different chromatographic techniques. Identification of compounds was realized through Rf values, shift reagents, and spectroscopic tools such as ultraviolet and nuclear magnetic resonance. The constituents of both unsaponifiable and methylated fatty acids were identified using Gas Liquid Chromatography (GLC) analysis. Essential oil constituents of peels and aerial part of C. reticulata were obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. PBS, 1% LMPA, and ethidium bromide were used for the comet assay and quantitative analysis of DNA fragmentation in liver tissue in male rats was determined. About 50 male mice were used in this study, which were allocated in five groups (10 animals each) and treated with BaP and C. reticulata [total ethanolic extract (TE) and petroleum ether fraction]. Results and conclusion Phytochemical investigation of the ethanolic extract from the aerial part of C. reticulata revealed five flavonoids (1–5). GLC analysis of the unsaponifiable fraction showed the presence of α-tocotrienol and α-tocopherol, which belong to the group of vitamin E. A total of 22 compounds were identified in the essential oils of C. reticulata blanco, 12 compounds were found in the aerial part, and 12 compounds were found in the fruit peels. The ethanolic extract was tested for the first time against genotoxicity induced by BaP in mice using the comet assay. TE significantly reduced the damage of DNA caused by BaP in mice. There was a statistically significant increase (P≤0.05) in the DNA fragmentation in the liver tissues of male mice and an increased rate of DNA damage in mice blood cells in the BaP group. Treatment with TE has a significant liver and blood cell protection by inhibiting the rate of DNA damage. These findings led us to conclude that the aerial part of C. reticulata is useful to reduce the genotoxicity induced by hazardous chemical agents.

Quark mass correction to chiral separation effect and pseudoscalar condensate

We derived an analytic structure of the quark mass correction to chiral separation effect (CSE) in small mass regime. We confirmed this structure by a D3/D7 holographic model study in a finite density, finite magnetic field background. The quark mass correction to CSE can be related to correlators of pseudo-scalar condensate, quark number density and quark condensate in static limit. We found scaling relations of these correlators with spatial momentum in the small momentum regime. They characterize medium responses to electric field, inhomogeneous quark mass and chiral shift. Beyond the small momentum regime, we found existence of normalizable mode, which possibly leads to formation of spiral phase. The normalizable mode exists beyond a critical magnetic field, whose magnitude decreases with quark chemical potential.

ВПЛИВ Eu(fod)3 НА СПЕКТРИ 1Н ЯМР 3-АРИЛІЗОКУМАРИНІВ ТА 3-АРИЛ-3,4 ДИГІДРОІЗОКУМАРИНІВ З АЛКОКСИЛЬНИМИ, ЕСТЕРНИМИ ТА АМІДНИМИ ГРУПАМИ

The effect of the lanthanide shift reagent (LSR) – tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octa-dionate) of Europium – Eu(fod)3 – on 1H NMR spectra of functionalized 3-arylisocoumarins and 3-aryl-3,4-dihydroisocoumarins was investigated. Based on previous studies of LSR interactions with benzopyrones, it was expected that the main coordination centre for the Eu3+ would be the exocyclic Oxygen atom of the heterocycle, but the possibility of competition from aromatic substituent functional groups was also considered. By measuring lanthanide-induced shifts (LIS) of the proton signals of the molecules at different ratios of substrate and Eu(fod)3, specific LIS values were determined. Based on those, it was concluded that the main direction of LSR coordination with 3-(2-hydroxy-5-methylphenyl)-1Hisochromen-1-one, 3-(2-methoxy-5-methylphenyl)-1H-isochromen-1-one and 3-(2-methoxy-5-methylphenyl)isochroman-1-one is the exocyclic Oxygen atom of the heterocycle, because the maximum LIS were recorded for the H-8 atom of isochromone system of these derivatives. In the case of ethyl ester of [2-(4-(1-oxo-1H-isochromen-3-yl)phenoxy] acetic acid and methyl ester of [2-(4-(1-oxoisochroman-3-yl)phenoxy]acetic acid comparable LIS values were observed both for H-8 and for the methylene group of the hydroxyacetic acid fragment, therefore, in such molecules the coordination of the Eu3+ to the heterocycle or to the aliphatic ester group is almost equally probable. In spectrum of methyl ester of N-{[4-(1-oxo-1H-isochromen-3-yl)phenoxy]acetyl}valine and N-{[4-(1-oxoisochroman-3-yl)-phenoxy]acetyl}valine there are insignificant LIS of H-8; and the maximum LIS were observed for the signals of the protons neighboring the two carbonyl groups of hydroxyacetic acid and valine fragments. Thus, these compounds interact w

Bioassay-guided isolation of cytotoxic flavonoids from aerial parts of Coronopus didymus

Ethnopharmacological relevance:Coronopus didymus Linn. (Brassicaceae) is a medicinal plant used traditionally as antipyretic, expectorant, to purify blood and for alleviating symptoms of pain, inflammations, malaria, wounds and cancer. Aim of the study:The present study was designed to isolate and identify the cytotoxic compounds responsible for anticancer activity from this traditionally useful medicinal plant. Materials and methods:Bioassay-guided fractionation of the ethanolic extract of aerial parts of C. didymus allowed the isolation of compounds responsible for anticancer activity. Their structures were elucidated by UV Spectroscopy (with shift reagents), ESI-MS and NMR spectral data. Preliminary anticancer activity of ethanolic extract, different fractions and isolated compounds was assessed through MTT in vitro cytotoxicity assay in a dose dependent manner against human cancer cell lines (HeLa and LN18) and normal 293T cells. Results:Three flavonoids namely 5,7,4′-trihydroxy-3′-methoxyflavone-4′-O-β-D-glucoside (1), 5,7,4′-trihydroxy-3′-methoxyflavone-4′-O-(6''-acetyl)-β-D-glucoside (2) and 5,7,4′-trihydroxy-3′-methoxy flavone (3), were isolated from aerial parts. Compound 1 was identified for the first time from the genus Coronopus. All the compounds 1–3 showed promising activity against HeLa cells with IC50 values of 43.50, 0.63 and 3.67 µM, respectively. Significant result was also obtained with compound 3 against LN18 cells with IC50 value of 46.63 µM. Conclusion:The cytotoxic activity of the crude extract and fractions which may largely be due to its major isolated constituents, flavonoids 1–3, against both HeLa and LN18 cells provides a scientific basis for the ethnopharmacological use of C. didymus as anticancer agent.

Increasing the Chemical-Shift Dispersion of Unstructured Proteins with a Covalent Lanthanide Shift Reagent.

The study of intrinsically disordered proteins (IDPs) by NMR often suffers from highly overlapped resonances that prevent unambiguous chemical‐shift assignments, and data analysis that relies on well‐separated resonances. We present a covalent paramagnetic lanthanide‐binding tag (LBT) for increasing the chemical‐shift dispersion and facilitating the chemical‐shift assignment of challenging, repeat‐containing IDPs. Linkage of the DOTA‐based LBT to a cysteine residue induces pseudo‐contact shifts (PCS) for resonances more than 20 residues from the spin‐labeling site. This leads to increased chemical‐shift dispersion and decreased signal overlap, thereby greatly facilitating chemical‐shift assignment. This approach is applicable to IDPs of varying sizes and complexity, and is particularly helpful for repeat‐containing IDPs and low‐complexity regions. This results in improved efficiency for IDP analysis and binding studies.

Dry Sintered Metal Coating of Halloysite Nanotubes

Halloysite nanotubes (HNTs) are a naturally-occurring aluminosilicate whose dimensions measure microns in length and tens of nanometers in diameter. Bonding defects between the alumina and silica lead to net negative and positive charges on the exterior and interior lumen, respectively. HNTs have been shown to enhance the material properties of polymer matrices and enable the sustained release of loaded chemicals, drugs, and growth factors. Due to the net charges, these nanotubes can also be readily coated in layered-depositions using the HNT exterior lumen’s net negative charge as the basis for assembly. These coatings are primarily done through wet chemical processes, the majority of which are limited in their use of desired chemicals, due to the polarity of the halloysite. Furthermore, this restriction in the type of chemicals used often requires the use of more toxic chemicals in place of greener options, and typically necessitates the use of a significantly longer chemical process to achieve the desired coating. In this study, we show that HNTs can be coated with metal acetylacetonates—compounds primarily employed in the synthesis of nanoparticles, as metal catalysts, and as NMR shift reagents—through a dry sintering process. This method was capable of thermally decaying the metal acetylacetonate, resulting in a free positively-charged metal ion that readily bonded to the negatively-charged HNT exterior, resulting in metallic coatings forming on the HNT surface. Our coating method may enable greater deposition of coated material onto these nanotubes as required for a desired application. Furthermore, the use of chemical processes using toxic chemicals is not required, thus eliminating exposure to toxic chemicals and costs associated with the disposal of the resultant chemical waste.

Spectroscopic and molecular dynamics characterization of glycyrrhizin membrane-modifying activity

Glycyrrhizic acid (GA) is a triterpene glycoside extracted from licorice root. Due to its amphiphilicity GA is capable of forming complexes with a variety of hydrophobic molecules, substantially increasing their solubility. GA can enhance the therapeutic effects of various drugs. It was hypothesized that the increased bioavailability of the drug by GA is not only due to increased solubility, but also to enhancement of drug permeability through cell membranes. In this study the interaction of GA with POPC liposomes and model DOPC, POPC and DPPC bilayers was investigated by NMR with addition of shift reagents and MD simulations. This work helps to better understand the mechanism of enhanced drug bioavailability in the presence of GA. NMR and MD reveal that GA does penetrate into the lipid bilayer. NMR shows that GA changes the mobility of lipids. GA is predominantly located in the outer “half-layer” of the liposome and that the middle of the hydrophobic tails is the preferred location. GA freely passes through the bilayer surface to the inner part bringing a few water molecules. Also both approaches indicate pore formation in the presence of GA. The GA interaction with membranes is an additional aspect of the biological activity of GA-based drug delivery systems.

The essential oil of Achillea ageratifolia (Sm.) Boiss. subsp. serbica (Nyman) Heimerl (Asteraceae) revisited: the stereochemical nomenclature issues, structural elucidation and synthesis of (new) sabinyl esters

AbstractSerbian Yarrow (Achillea ageratifolia (Sm.) Boiss. subsp. serbica (Nyman) Heimerl, Asteraceae) is a poorly investigated taxon, endemic to the Central Balkan Peninsula area. A combination of chromatographic and spectroscopic techniques enabled the identification of, in total, 300 constituents (comprising 95.5–97.2% of the total essential oil compositions) from the essential oils of the A. ageratifolia ssp. serbica dry aerial parts. A comparison of the essential‐oil compositions from plant material collected from two populations (Jelašnička klisura gorge and Suva Planina mountain, SE Serbia) in two consecutive years (2013 and 2014) confirmed that the biosynthesis/accumulation of the volatile metabolites for this species is not dependent on the environmental conditions and suggested the existence of a single chemotype of this species. The essential oil compositions were dominated by (1R*,3S*,5R*)‐sabinyl derivatives, including two completely new natural products: (1R*,3S*,5R*)‐sabinyl nonanoate and (1R*,3S*,5R*)‐sabinyl decanoate. The identity of these new esters was unambiguously confirmed by co‐injection of the essential oil samples with synthesized standards and their structure was elucidated by NMR (1D and 2D), IR and MS, whereas the stereochemistry of the esters was studied by an NMR methodology that employed lanthanide‐induced shift reagents. Additionally, a nomenclature confusion regarding the relative stereochemistry of sabinyl esters, that came from the opposing use of cis and trans for the parent alcohols and the derived esters, was addressed. We propose the use of CIP notation in connection with the trivial names to avoid further ambiguities. Copyright © 2016 John Wiley & Sons, Ltd.

Compact NMR Spectroscopy with Shift Reagents

To simplify a nuclear magnetic resonance (NMR) spectra of the targeted molecules, spin–spin decoupling and selective isotope substitution are two distinct approaches. A third one is to increase the applied magnetic field to increase the frequency dispersion of the chemical shift range. While this is a viable option for NMR spectrometers with superconducting magnets, the new generation of compact NMR spectrometers employs permanent magnets with limited variety in field strengths between one and two Tesla. The low-frequency dispersion at these field strengths gives rise to higher order spectra more frequently than at high field. These low-field spectra can be simplified using lanthanide shift reagents, which form complexes with the substrate molecule and increase the frequency dispersion. In this work, the use of lanthanide shift reagents is demonstrated by means of one-dimensional 1H and 19F as well as two-dimensional 19F-19F COSY experiments using a new-generation compact NMR spectrometer.

Mobility shifts when buffer gas temperature increases in ion mobility spectrometry are affected by intramolecular bonds

When buffer gas temperatures increase in ion mobility spectrometry (IMS), ions lose hydration molecules and their mobilities increase. Also, shift reagents (SRs, dopants or modifiers) introduced in the buffer gas, form adducts with the ions and their ion mobilities decrease. Some ions, such as methionine and diamines, are not largely influenced by the introduction of SRs or the buffer gas temperatures because they form intramolecular hydrogen bonds (IHBs). We used electrospray ionization IMS coupled to quadrupole mass spectrometry to study the drift behavior of these ions using data obtained at different temperatures or with different SRs. In this study, we explain the unusually small mobility shifts in methionine and diamine ions when buffer gas temperature increases in IMS based on the breaking of IHBs that increase the ions’ collision cross-sections. We also explain the small mobility shifts in these ions when buffer gas SRs are introduced in the drift tube based on the formation of these IHBs, This study is important because when temperature increases in IMS, mobility shifts had been considered to be affected exclusively by declustering and the increase in collision frequency. This information will help understand the behavior of IHB-forming ions in IMS at different temperatures and when buffer gas SRs are introduced in the drift tube, and could be used to demonstrate the presence of these bonds and measure their binding energy.

Synthesis, NMR, photoluminescence studies and intramolecular energy transfer process of europium(III) complexes

Abstract The studies related to the synthesis and luminescence properties of five europium(III) complexes of the type [Eu(OFHD)L] where OFHD is deprotonated 1,1,1,5,5,6,6,6-octafluorohexane-2,4-dione and L is H 2 O ( C1 ), 2,2′-biquinoline ( C2 ), neocuproine ( C3 ), 1,10-phenanthroline ( C4 ) and 2,2′- bipyridyl ( C5 ) are reported in the present communication. The synthesized complexes were investigated by means of elemental analysis, IR, 1 H NMR, UV–vis spectroscopy and TGA techniques. The high fluorination in the complexes makes them best candidates of NMR shift reagents to resolve the spectra as revealed in 1 H NMR study. The excitation and emission spectra of complexes in solid state were investigated in detail. Further, on the basis of emission spectra, the CIE color coordinates (x and y), luminescence decay time (τ), radiative decay rate (A rad ), nonradiative rate (A nrad ), quantum efficiency (η) and Judd-Ofelt intensity parameter (Ω 2 ) were calculated and analyzed. The interaction of lowest triplet levels of ligands with the emitting levels of europium(III) ion is represented by proposed intramolecular energy transfer mechanism. The beauty of these complexes is that they can be used as NMR shift reagents and are of particular interest in the field of light emitting materials.