Optical Absorption, Kinetics and Thermodynamic Studies of Pr(III) and Nd(III) Ions with N-Acetyl L-Cysteine in Presence of Ca(II) ions

Interaction of N-acetyl-L-cysteine (NAC) with Pr3+ (Pr(NO3)3·6H2O) and Nd3+ (Nd(NO3)3·6H2O) ions are studied in presence of Ca2+ (Ca(NO3)3·4H2O) ion in an aqueous and organic solvent by applying the spectroscopic technique for quantitative probe of 4f-4f transition. The complexation was determined by the variation in the intensities of 4f-4f absorption spectral bands and by applying the change of symmetric properties of electronic-dipole known as Judd-Ofelt parameters Tλ (λ = 2,4,6). On the addition of Ca2+ ion in the binary complexation of praseodymium and neodymium with N-acetyl-L-cysteine (NAC) there is an intensification of bands which shows the effect of Ca2+ toward the heterobimetallic complex formation. Other parameters like Slater-Condon (Fk), bonding (b1/2), the Nephelauxetic ratio (β), percentage covalency (δ) are also used to correlate the complexation of metals with N-acetyl-L-cysteine (NAC). With the minor change in coordination around Pr3+ and Nd3+ ions, the sensitivity of 4f-4f bands is detected and further used to explain the coordination of N-acetyl-L-cysteine (NAC) with Pr3+ and Nd3+ in presence of Ca2+. The variation in oscillator strength (Pobs), energy (Eobs) and dipole intensity parameter help in supporting the heterobimetallic complexation of N-acetyl-L-cysteine. In kinetics investigation, the rate of the complexation of both hypersensitive and pseudo-hypersensitive transition is evaluated at various temperature in DMF solvent. The value of the thermodynamic parameters such as ΔHo, ΔSo and ΔGo and activation energy (Ea) also evaluated.

New Europium(III)-TTA Complex Containing 2-Pyrrolidone as Coligand to Application as Luminescent Sensor: PbII and Ethanol in Gasoline

This work describes the synthesis and application of an europium(III) complex, [Eu(TTA)3(2-pyr)(H2O)], containing 2-thenoyltrifluoroacetonate (TTA) and 2-pyrrolidone (2-pyr) as ligands, obtained as white solid and soluble in ethanol. In solution, the complex showed red emission, characteristic of the EuIII emission in the solid state (λexc = 375 nm and λem = 612 nm). The complex was tested with PbII, CdII, and HgII ions in water. The effect of metal ions was monitored and evaluated by hypersensitive transition 5D0 → 7F2 (612 nm). The results show that PbII suppresses the complex luminescence and present high sensitivity, according to the values for the Stern-Volmer constant (KSV = 2300 L mol-1), showing good linearity, i.e., determination coefficient (R2) of 0.9913, and low limit of detection (LOD = 6.03 µM). Luminescence quenching increased with the increasing concentration of PbII. These results indicate that the synthesized complex is a potential luminescent sensor for detecting PbII in a simple and fast way, being applicable for routine environmental analysis. When applied as an ethanol sensor in gasoline, the complex hypersensitive transition intensity decreased with the increasing volume of ethanol in gasoline, reaching the values of R2 = 0.9815 and LOD = 4.94% v/v.

Colorimetry of Luminescent Lanthanide Complexes

Europium, terbium, dysprosium, and samarium are the main trivalent lanthanide ions emitting in the visible spectrum. In this work, the potential of these ions for colorimetric applications and colour reproduction was studied. The conversion of spectral data to colour coordinates was undertaken for three sets of Ln complexes composed of different ligands. We showed that Eu is the most sensitive of the visible Ln ions, regarding ligand-induced colour shifts, due to its hypersensitive transition. Further investigation on the spectral bandwidth of the emission detector, on the wavelengths’ accuracy, on the instrumental correction function, and on the use of incorrect intensity units confirm that the instrumental correction function is the most important spectrophotometric parameter to take into account in order to produce accurate colour values. Finally, we established and discussed the entire colour range (gamut) that can be generated by combining a red-emitting Eu complex with a green-emitting Tb complex and a blue fluorescent compound. The importance of choosing a proper white point is demonstrated. The potential of using different sets of complexes with different spectral fingerprints in order to obtain metameric colours suitable for anti-counterfeiting is also highlighted. This work answers many questions that could arise during a colorimetric analysis of luminescent probes.

Magnetofluorescent Nanocomposite Comprised of Carboxymethyl Dextran Coated Superparamagnetic Iron Oxide Nanoparticles and β-Diketon Coordinated Europium Complexes

Red emitting europium (III) complexes Eu(TFAAN)3(P(Oct)3)3 (TFAAN = 2-(4,4,4-Trifluoroacetoacetyl)naphthalene, P(Oct)3 = trioctylphosphine) chelated on carboxymethyl dextran coated superparamagnetic iron oxide nanoparticles (CMD-SPIONs) was synthesized and the step wise synthetic process was reported. All the excitation spectra of distinctive photoluminesces were originated from f-f transition of EuIII with a strong red emission. The emission peaks are due to the hypersensitive transition 5D0→7F2 at 621 nm and 5D0→7F1 at 597 nm, 5D0→7F0 at 584 nm. No significant change in PL properties due to addition of CMD-SPIONs was observed. The cytotoxic effects of different concentrations and incubation times of Eu(TFAAN)3(P(Oct)3)3 chelated CMD-SPIONs were evaluated in HEK293T and HepG2 cells using the WST assay. The results imply that Eu(TFAAN)3(P(Oct)3)3 chelated CMD-SPIONs are not affecting the cell viability without altering the apoptosis and necrosis in the range of 10 to 240 μg/mL concentrations.

Physical and optical properties of sodium borate glasses doped with Dy3+ ions

The photoluminescence, optical and physical properties of sodium borate (NB) doped with different concentrations of Dy[Formula: see text] were determined and well discussed. The samples were prepared by the melt-quenching technique and characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Photoluminescence and absorption spectra of NB glasses doped with different concentrations of Dy[Formula: see text] are reported. Ten absorption bands with hypersensitive transition at 1272 nm ([Formula: see text] [Formula: see text][Formula: see text]) and two emission bands for the transitions at [Formula: see text] [Formula: see text][Formula: see text] (blue color) and [Formula: see text] [Formula: see text][Formula: see text] (yellow color) with an excitation of 330 nm have been recorded. A series of considerable physical properties (oscillator strengths, refractive index, ions concentration, polaron radius) was calculated for each dopant concentration.

Optical and Luminescence Properties of Dy3+ Doped in Soda Lime Borate Glasses

The aim of this study is to develop soda lime borate (SLB) doped with Dy3+ glass and investigate their optical and luminescence properties, for different applications in photonics and optoelectronics. The glass were melt by conventional melt quenching technique. Optical properties have been determined by measuring their absorption spectra and luminescence properties were studied by photo luminescence spectra. From optical absorption measurements, there are ten peaks with transition 6H15/2 to 6F11/2 + 6H9/2 at 1262 nm has higher spectral intensity and is a hypersensitive transition. As a result of 350 nm excitation the photoluminescence spectra have four peaks. Higher luminescence intensity peak was observed for 0.5 mol% Dy3+ doped SLB glass at 4F9/2 to 6H13/2 (575 nm). Hence it is suggest from the chromaticity results that SLB glasses with different Dy2O3 concentration may be a promising glass for white LED under 350 nm excitation wavelength. Further investigation is under way for the optimization of different dopend concentration in the SLB glass.

Physical and optical properties of magnesium sulfoborate glasses doped Dy3+ ions

The optical properties of alkaline earth borate glasses doped with rare earth are attractive field of research due to many optical applications. We have concentrated on the physical and optical properties of MgO–SO4–B2O3 glass with different concentrations of Dy[Formula: see text] ions. The samples of glass were prepared using the melting quenching technique. The physical parameter and optical properties of the prepared glass were determined. It was observed that the density of the glass samples increased and the molar volume reduced with respect to Dy[Formula: see text] ions content. Dy[Formula: see text]: MgO–SO4–B2O3 glass displayed 10 absorption bands with hypersensitive transition around 1265 nm (6H[Formula: see text]F[Formula: see text]). Two intense luminescence emissions were observed at 482 nm (4F[Formula: see text]H[Formula: see text]: blue) and 573 nm (4F[Formula: see text]H[Formula: see text]: yellow) and weak band at 662 nm (4F[Formula: see text]H[Formula: see text]: red) with excitation wavelength 380 nm. A strong enhancement in the emission peaks at 573 nm in the yellow region was observed with the 0.07 mol% concentration of dysprosium oxide, which may assign to the energy transfer from Mg[Formula: see text] to Mg[Formula: see text] ions. Beyond the optimum concentration, contrary result was observed.

Structural and Optical Properties of Nd3+ Doped Na2O-PbO-ZnO-Li2O-B2O3 Glasses System

The present paper reports the structural (XRD and FTIR spectra), physical (like density, molar volume, refractive index etc.), optical absorption and emission properties of Nd3+ doped sodium lead zinc lithium borate glass. The glasses with chemical formula (65-x)B2O3-15Na2O-10PbO-5ZnO-5Li2O-xNd2O3 (where x = 0, 0.05, 0.1, 0.5, 1.0, 2.0 and 4.0) have been prepared using the melt-quenching method. XRD characterization shows that the glasses are amorphous nature. The values of measured absorption transitions obtained ten transitions and the hypersensitive transition at 4I9/2 → 2G7/2+4G5/2. To excite photon from ground state to upper state, used two different wavelength spectra at 582 and 804 nm. The maximum emission intensity of the 4F3/2 → 4I11/2 transition obtained when Nd3+ ion content in the borate glass is 1.0 mol %. It is indicating that Nd3+ doped borate glass have self-quenching or concentration quenching.