Preparation of lanthanide sulfide films by chemical vapor deposition using β-diketone chelates

Preparation of thin films of lanthanide (Ln) sulfides has been studied by the chemical vapor deposition (CVD) method, using metal -diketonato chelates with 2,2,6,6-tetramethyl-3,5-heptanedione and reactant H₂S gas as starting materials. Two kinds of sulfides, Ln₂O₂S oxysulfides and EuS monosulfide, were obtained as thin films at temperatures as low as 390–570 °C. The CVD method was confirmed to be suited for the above purpose.     

Efficient two-photon-sensitized luminescence of a novel europium(III) β-diketonate complex and application in biological imaging

A novel europium(III) β-diketonate complex exhibiting bright two-photon-sensitized luminescence is synthesized and applied as a two-photon-sensitized luminescent probe to stain DNA in live cells.     

Luminescent organic–inorganic hybrid materials based on lanthanide containing ionic liquids and sylilated β-diketone

In this work, we report the luminescent organic–inorganic hybrid materials prepared by hydrolysis and condensation of sylilated β-diketone under acid conditions in the presence of carboxyl-functionalized ionic liquid in which Eu³⁺ ions are coordinated to the oxygen atoms of carboxylate groups from the ionic liquids. The obtained materials were characterized with FT-IR, TG and photoluminescence spectroscopy. FT-IR spectra imply that Eu³⁺ ions are still coordinated to the ionic liquid in the hybrid materials. Excitation and emission spectra demonstrate that the energy transfer occurs from the β-diketone molecules covalently bonded with silica to Eu³⁺ ions. The Eu³⁺ (⁵D₀) quantum efficiency value of the hybrid materials has been estimated based on the emission spectrum and the value of lifetime. A large value of ratio (16.44) between the intensities of the ⁵D₀→⁷F₂ and ⁵D₀→⁷F₁ transition and high value of ⁵D₀ quantum efficiency (51.01%) are obtained.     

Preparation of lanthanide,thorium and uranium oxide films by chemical vapor deposition using β-diketone chelates

Preparation of thin film deposits of lanthanide, thorium and uranium oxides has been studied by chemical vapor deposition (CVD) method using -diketonate metal chelates with 2,2,6,6-tetramethyl-3,5-heptanedione and some reactant gases as starting materials. The deposition process was carried out using a special apparatus designed for the CVD method at atmospheric pressure and temperatures as low as 400–600°C.As a result, it was demonstrated that each chelate used was well suited for the above purpose by its high volatility and reactivity with the reactant, especially with water vapor.     

‘Low-temperature method’ for a dramatic improvement in enantioselectivity in lipase-catalyzed reactions

Temperature control in lipase-catalyzed resolutions has been recently focused attention due to its simplicity and reliability for enhancement of the enantioselectivity. Lowering the reaction temperature usually increases the enantioselectivity. Lipase immobilized on porous ceramics was found to greatly accelerate the low-temperature reaction, and made the method practical. Our discovery, properties, and practical uses are summarized, and its applications are reviewed.     

Functionalised β-diketone assisted self-assembly of a hexanuclear yttrium oxo-hydroxo cluster

The reaction of YCl₃·6H₂O with ortho-hydroxydibenzoylmethane (HO-DBMH) in a 1:2 ratio, in methanol and in the presence of excess triethylamine as a base yielded a yellow precipitate which on crystallization from toluene or benzene /hexane afforded pale yellow block-like crystals. Single crystal X-ray diffraction of 1 revealed the formation of an interesting hexanuclear yttrium oxo-hydroxo cluster [Y₆(O-DBM)₆(HO-DBM)₄(μ₃-OH)₂(MeOH)₄]; the core resembles a butterfly framework flanked by a lanthanide atom on each side. Ten phenolic β-diketone ligands are present in the cluster, which bridge the metal centers in both chelating and chelating-bridging fashions.     

Unusual shift of a nitro group in a phenylhydrazo-β-diketone

A novel para to meta shift of a nitro group at the phenyl ring of 3-(2-hydroxy-4-nitrophenylhydrazo)pentane-2,4-dione (H(2)L(1), 1), with formation of the new 3-(2-hydroxy-3,5-dinitrophenylhydrazo)pentane-2,4-dione (H(2)L(2), 2), occurs upon nitration of 1 with an equimolar amount of NaNO(2), under basic conditions. 2 acts as a polydentate ligand for the synthesis of the polymeric potassium [K(μ(5)-HL(2))](n) (3) and monomeric nickel(II) [Ni(H(2)O)(3)(L(2))]·H(2)O (4) compounds. They have been fully characterized, including single crystal X-ray analysis, and the complexes feature metal-organic (in 3) or supramolecular (in 4) 3D networks. The topological analysis of 3 reveals a uninodal 5-connected underlying net with the point symbol of (4(6).6(4)) and a very rare 5/4/t5 topology, which had not yet been observed in coordination polymers.     

Sensitization of europium(Ⅲ) luminescence in water with β-diketone-poly(ethylene glycol) macroligand

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Sensitization of europium(III) luminescence in water with β-diketone-poly(ethylene glycol) macroligand

Poly(ethylene glycol)-modified-diketone macroligand is developed to sensitize europium(Ⅲ)ions in water.High luminescence intensity characteristic of Eu3+ was achieved due to spontaneous formation of micelle-like structure in which the hydrophobic core prevents luminescence-quenching by water molecules.The pH is found to induce a quantitative ratio change in two fluorescence bands from both ligand and Eu3+.     

Iron luminescence thermal effects in sodium β″-alumina

Powder NaAl₅O₈ doped with Fe³⁺ emits two broadbands at 705 and 758 nm. The shape of the combined emission depends on the annealing time of the samples and it is affected by the temperature of the samples, even below room temperature. It is concluded that these features are due to the occupation of at least two crystallographic inequivalent sites by the Fe ions in the sodium β″-aluminate: the BR sites (I) in the conduction region and Al(3) sites (II) of the spinel blocks near to the conduction plane. It is proposed that iron diffusion from I sites to vacant II sites should also occur in the temperature range below room temperature after the samples are submitted to long annealing times at synthesis temperature.     

Supramolecular assembly of a new squaraine and β-cyclodextrin for detection of thiol-containing amino acids in water

A new unsymmetrical aniline-based squaraine (SQ2) bearing binding unit of Hg²⁺ ion was designed and synthesised. SQ2 can form 1:2 inclusion complex with β-cyclodextrin, and the resulting complex, which undergoes absorption and fluorescence bleaching upon binding Hg²⁺, can serve as a turn-on colorimetric or fluorescent chemosensor in organic solvent-free aqueous solution for thiol-containing amino acids with high selectivity and tunable measuring range.     

Coordination compounds of uranium and thorium with a novel double β-diketone

A novel double -diketone 1,6-bis(1-phenyl-3-methyl-5-oxo-pyrazol-4-yl) hexanedione-[1,6] (BPMOPH) was further studied on its coordination compounds with uranium and thorium, respectively. The IR, UV, and¹H-NMR spectra were examined, and the proposed structure is discussed.     

Blue electroluminescence of a novel Zn~(2+)–β-diketone complex with a carbazole moiety

In this letter, a novel zinc complex of Zn(ECTFBD)2 was synthesized by an environment-friendly grinding technique in high yield. Its structure was confirmed by1H NMR, MS and EA. HECTFBD is 1-(9-ethyl-9Hcarbazol-3-yl)-4,4,4-trifluorobutane-1,3-dione. Zn(ECTFBD)2-based light-emitting devices were fabricated. The architecture of the devices was ITO/PEDOT(40 nm)/100 wt% PVK: 40 wt% OXD-7: x wt% Zn(ECTFBD)2(85 nm)/CsF(1.5 nm)/Al(100 nm), where x = 1, 5, and 10(relative to the mass of PVK and OXD-7). The three devices displayed blue emissions with peaks at 450, 458, and 460 nm, respectively. A maximum luminous efficiency of 0.86 cd/A and a luminance of 228 cd/m2were achieved by the 1 wt% doped device. So, we demonstrated further that Zn2+–b-diketone complexes can be effectively severed as a class of new electroluminescent materials. In addition, the thermal stability of Zn(ECTFBD)2 was tested and the UV–vis and photoluminescent behaviors of Zn(ECTFBD)2 in CH2 Cl2 were investigated.     

Searching for precision of a new “luminescence clock” in dating calcitic rocks

The novel method of thermoluminescence (TL) dating of megalithic (cyclopean) limestone monuments and/or marble statues will be briefly reviewed. The problems and recent examples to be discussed include: (a) the determination of the accumulated archaeological dose, Dar, (b) the sample homogeneity, (c) the scattering in TL measurements, (d) the rate in solar bleaching of TL, and (e) dose-plateau inconsistencies. In retrospect, the solar bleaching of TL in some marbles refers to at least 30 mm depth, the scattering of TL measurements at best varies around ±10%, and the partial bleaching technique should be prudently applied for Dar determination. The extension of this method to date (by TL or OSL) for other rock types is discussed.     

Thermodynamics of inclusion complex formation of hydroxypropylated α- and β-cyclodextrins with aminobenzoic acids in water

Calorimetry, densimetry, ¹H NMR and UV–vis spectroscopy were used to characterize inclusion complex formation of hydroxypropylated α- and β-cyclodextrins with meta- and para-aminobenzoic acids in aqueous solutions at 298.15 K. Formation of more stable inclusion complexes between para-aminobenzoic acid and cyclodextrins was observed. The binding of aminobenzoic acids with hydroxypropyl-α-cyclodextrin was found to be enthalpy-governed owing to the prevalence of van der Waals interactions and possible H-binding. Complex formation of hydroxypropyl-β-cyclodextrin with both acids is mainly entropy driven. The increased entropy contribution observed in this case is determined by dehydration of solutes occurring during the revealed deeper insertion of aminobenzoic acids into the cavity of hydroxypropyl-β-cyclodextrin. By comparing complex formation of aminobenzoic acids with native and substituted cyclodextrins it was found that the availability of hydroxypropyl groups slightly influenced the thermodynamic parameters and did not change the binding mode or driving forces of interaction.     

Fluorescent ratioable recognition of Cu in water using a pyrene-attached macrocycle/γ-cyclodextrin complex

A pyrene-functional fluoroionophore, 1 was used to construct a supramolecular 1/γ-CD complex for Cu²⁺ recognition in water. In aqueous γ-CD solution, 1 exhibits pyrene monomer fluorescence emission at 378 nm and 397 nm, while in the presence of Cu²⁺, it shows a pyrene excimer emission at 452 nm with a decrease in the monomer fluorescence due to the formation of a 1:2 metal-liganded complex. Based on the response characteristics of the supramolecular complex, a fluorescent ratiometric method was performed for the determination of Cu²⁺ concentration in water. With the optimum conditions described, Cu²⁺ in aqueous solution can be determined from 1.2 × 10⁻⁶ to 4.5 × 10⁻⁴ M. The Cu²⁺ selectivity of the complex is excellent, and the excimer fluorescence enhancements are very smaller induced by other heavy metal and transition metal ions.     

Phthalates in surface water — a method for routine trace level analysis

Summary A routine method for the determination of phthalates in water is presented. It is suitable for all kinds of water like surface water, waste water, landfill leachate, rain water and ground water. Unfiltered water samples including all suspended particulate matter are extracted by solid-phase extraction in an all-glass apparatus using RPC-18. The extracts are measured by GC/MSD in the SIM mode. Due to an easy but efficient decontamination technique, method blanks could be decreased below 0.02 g/l for all phthalates. The detection limits are 0.01 to 0.02 g/l, the determination limits are 0.02 to 0.05 g/l. Recovery for all phthalates is about 98% (±5%). Phthalates were measured in about 400 samples of water of the river Rhine and its main affluents in Northrhine-Westfalia.     

Properties of TRPO-HNO_3 complex used for direct dissolution of lanthanide and actinide oxides in supercritical fluid CO_2

The mixed trialkylphosphine oxide-nitric acid (TRPO-HNO3) complex prepared by contacting pure TRPO with concentrated HNO3 may be used as additives for direct dissolution of lanthanide and actinide ox- ides in the supercritical fluid carbon dioxide (SCF-CO2). Properties of the TRPO-HNO3 complex have been studied. Experimental results show when the initial HNO3/TRPO volume ratio is varied from 1:7 to 5:1, the concentration of HNO3 in the TRPO-HNO3 complex changes from 2.12 to 6.16 mol/L, the [HNO3]/[TRPO] ratio of the TRPO-HNO3 complex changes from 0.93 to 3.38, and the content of H2O in the TRPO-HNO3 complex changes from 0.97% to 2.70%. All of the density, viscosity and surface tension of the TRPO-HNO3 complex change with the concentration of HNO3 in the complex. The protons of HNO3 and H2O in the complex undergo rapid exchange to exhibit a singlet resonance peak in NMR spectra with D2O insert. When the TRPO-HNO3 complex dissolves in a low dielectric constant solvent, small droplets of HNO3 appear which can be detected by NMR.     

Syntheses and spectroscopic studies of volatile low symmetry lanthanide(III) complexes with monodentate 1H-indazole and fluorinated β-diketone

Synthesis, photoluminescence, 4f–4f absorption, and NMR studies of highly volatile nine-coordinate complexes [Ln(hfaa)₃(L)₃] (Ln?=?La, Pr, Nd, and Sm; hfaa is the anion of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione and L?=?1H-indazole) are described. NMR spectra reveal that three L are attached to the metal. The chemical shifts of β-diketonate and Hind protons are in opposite directions and the lanthanide induced paramagnetic shifts are dipolar. The low molecular symmetry of the complexes leads to intense luminescence with prominent Stark splitting of the bands and high oscillator strength of the hypersensitive transition. The band shape of the ⁴G_5/2, ²G_7/2?←?⁴I_9/2 transition of neodymium is similar to that of nine-coordinate complexes. Coordinating solvents have pronounced effect on the oscillator strength and band shape. The experimental intensity parameter (η _Sm) for the samarium complex is calculated and analyzed. The complexes could be used as precursors for high-performance lanthanide-based materials through chemical vapor deposition.     

DFT structural and optical nonlinear investigations of a synthesized new azo β-diketone dye

A new azo β-diketone (NA1) compound is synthesized by coupling reaction of 4-aminoantipyrine with acetylacetone. The NA1 compound is characterized via FTIR, Mass, ¹H NMR and ¹³C NMR spectroscopies. The keto-enol tautomers of the compound electronic structures and energies are investigated using density functional theory (DFT) via B3LYP method/6-311G (d,p) level. The NA1 compound nonlinear optical (NLO) properties are studied via the diffraction patterns (DPs) and the Z-scan where the compound nonlinear index of refraction (NIR), the optical limiting (OLg) property using 473 nm visible, low power, continuous (cw) laser beam are used while the all-optical switching (AOS) property is studied using two laser beams of wavelengths 473 nm and 532 nm.