Synthesis and Crystal Structure of CeIII and BiIII Complexes and Solution Studies of ZnII,CdII, PbII,CeIII, and BiIII Complexes Obtained from Proton Transfer Compounds Containing 2,6‐Pyridinedicarboxylate Ion

The two complexes (pydaH)₂[Ce(pydc)₂(H₂O)₂]₂ · 2H₂O (1) and (phenH)₂[Bi(pydc)₂(H₂O)]₂ · 5H₂O (2) were prepared from the proton transfer compounds containing the 2,6‐pyridinedicarboxylate ion. 1 was synthesized from the reaction of Ce(NO)₃ · 6H₂O with the proton transfer compound, (pydaH₂)(pydc), (pyda=2,6‐diaminopyridine, pydcH₂=2,6‐pyridinedicarboxylic acid). 2 was synthesized from the reaction of proton transfer compound, (phenH)₂(pydc), (phen=1,10‐phenanthroline), with Bi(NO₃)₃ · 5H₂O. The characterization was carried out using IR, ¹H and ¹³C NMR spectroscopy, elemental analysis and single crystal X‐ray diffraction. The complex 1 crystallizes in the space group of the triclinic system, and contains two molecules per unit cell. The structure has been refined to a final value for the crystallographic R factor of 0.0342 based on 8851 reflections. The unit cell parameters are: a = 9.753(2) Å, b = 10.503(2) Å, c = 10.774(2) Å, α = 83.905(4)°, β = 88.089(4)°, and γ = 82.636(3)°. The crystal structure illustrates that cerium atoms are connected together through the four‐membered ring Ce₂O₂. 2,6‐Pyridinedicarboxylate fragment acts as a tridentate ligand. The molecular structure contains four (pydc)^2? ligands, two of which are bridge ligands linking the two central atoms. The complex 2 crystallizes in the space group of the triclinic system and contains two molecules per unit cell. The unit cell dimensions are: a = 8.8860(4) Å, b = 12.0132(6) Å, c = 13.0766(6) Å, α = 100.967(1)°, β = 96.681(1)° and γ = 94.191(1)°. The structure has been refined to a final value for the crystallographic R factor of 0.0471 based on 9576 reflections. In this complex, 2,6‐pyridinedicarboxylate moiety has acted as a tridentate ligand and the lattice is composed of binuclear unit, [Bi(pydc)₂(H₂O)]₂^2?, (phenH)⁺ counter ions and five lattice waters. In both complexes hydrogen bonds, π‐π stacking and ion‐pairing play important roles in stabilizing the corresponding lattice. The stoichiometry and stability of the Zn^II, Cd^II, Pb^II, and Ce^III complexes with (pydaH₂)(pydc) in aqueous solution were investigated by potentiometric pH titration. The solution studies revealed that the stoichiometry of the crystalline complexes of the proton transfer system (pydaH₂)(pydc) with Ce^III, obtained in this study, and those with Zn^II, Cd^II and Pb^II, reported in our previous studies, are in close agreements. The complexation reactions of phen, pydc, and 2phen+pydc with Bi^III in aqueous solution were investigated by potentiometric pH titrations, and the equilibrium constants for all major complexes formed are described.     

Time-gated luminescence microscopy with responsive nonmetal probes for mapping activity of protein kinases in living cells

A photoluminescence probe ARC-1185, possessing both high affinity towards basophilic protein kinases (PKs) and microsecond-scale luminescence lifetime when associated with a kinase, was used for the mapping of ARC-1185-PK complexes in living cells with time-gated luminescence microscopy.     

Qualitative and quantitative assessment of extracted oil from Camelina sativa seed treated by dielectric-barrier discharge cold plasma

This study aimed to investigate the effects of dielectric-barrier discharge (DBD) cold plasma (CP) pretreatment on Camelina sativa “Soheil cultivar” seed. A DBD plasma reactor system was employed for this purpose. The experiments were performed by taking into account variables including voltages of 15, 18, and 21 kV and times of 2, 4, 8, and 16 min. The measured properties were oil yield extraction (%), oil colour parameters (CIEL*a*b*), protein content (meal) (%), surface analysis using Scanning Electron Microscopy (SEM), and fatty acids profile of Camelina sativa. The results revealed that the CP treatment had a significant improvement in different properties of the extracted oil. It was observed that the extracted oil was increased, with the increasing time of CP exposure. The treatments of CP enhanced the oil yield from 24.3 to 31.5%, and the optimal conditions were identified as 21 kV and 16 min. Also, the maximum protein amount was observed for the samples treated by CP (39.5%). The SEM analysis showed that the cell structures of pre-treated Camelina samples were damaged, thereby improved the oil extraction efficiency. The variations in the values of L*, a*, and b* (max-min) were calculated to be 3.9, −2.5, and 9.7, respectively, which indicated minor changes of CP treatment on the oil colour parameters. The treated samples showed considerable changes of enhancement in linolenic and linoleic acids among poly-unsaturated fatty acids; and a reduction in palmitic acid content, among saturated fatty acids.     

Influence of the third monomer on lauryl methacrylate–methyl methacrylate emulsion terpolymerization

An experimental study shows how the emulsion terpolymerization of lauryl methacrylate (LMA) and methyl methacrylate is influenced by the nature of the third monomer. The third monomer is either glycidyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, or styrene. We report the synthesis of terpolymer particles with an appreciably high content of the very hydrophobic LMA (between 0.2515 and 0.238 molar fraction in the monomer mixture) in 60:40 weight water/ethanol mixture as the continuous phase, poly(vinyl pyrrolidone) as a polymeric steric stabilizer, and potassium peroxodisulfate as the initiator. The emulsion terpolymerization proceeds smoothly without the formation of coagulum and leads to particles with an average diameter clearly below 1 μm. We discuss the overall polymerization behavior regarding conversion–time curves, particle morphology, and glass transition temperature of the terpolymers in dependence of the lyophilicity/lyophobicity of the monomer mixture.     

Flow injection on-line determination of uranium after preconcentration on XAD-4 resin impregnated with dibenzoylmethane

A flow injection on-line determination of uranium(VI) after preconcentration in a minicolumn having amberlite XAD-4 resin impregnated with dibenzoylmethane (DBM) is described. Uranium(VI) is selectively adsorbed from aqueous solution of pH 5.5 in the minicolumn (5.5 cm long with 5.0 mm i.d.) at a flow rate of 13.6 mL min⁻¹. The uranium(VI) complex was desorbed from the resin by 0.1 mol dm⁻³ HCl at a flow rate of 4.2 mL min⁻¹ and mixed with arsenazo-III solution (0.05% solution in 0.1 mol dm⁻³ HCl, 4.2 mL min⁻¹), and taken to the flow through cell of spectrophotometer where its absorbance was measured at 651 nm. Various parameters affecting the complex formation and its elution were optimized. Peak height (absorbance) was used for data analyses. The preconcentration factors of 36 and 143, detection limits of 0.9 and 0.232 μg L⁻¹, sample throughputs of 40 and 10 were obtained for preconcentration time of 60 and 300 s, respectively. The tolerance limits of many interfering cations like Th(IV) and rare-earth elements were improved. The proposed method was applied on different water (spiked tap, well and sea water) and biological samples and good recovery was obtained. The method was also validated on mocked uranium ore sample and the results were in good agreement with the reported value.     

A new HPLC method for the simultaneous determination of ascorbic acid and aminothiols in human plasma and erythrocytes using electrochemical detection

A new, simple, economical and validated high-performance liquid chromatography linked with electrochemical detector (HPLC-ECD) method has been developed and optimized for different experimental parameters to analyze the most common monothiols and disulfide (cystine, cysteine, homocysteine, methionine, reduced (GSH) and oxidized glutathione (GSSG)) and ascorbic acid present in human plasma and erythrocytes using dopamine as internal standard (IS). Complete separation of all the targets analytes and IS at 35 °C on Discovery HS C18 RP column (250 mm × 4.6 mm, 5 μm) was achieved using 0.05% TFA:methanol (97:3, v/v) as a mobile phase pumped at the rate of 0.6 ml min⁻¹ using electrochemical detector in DC mode at the detector potential of 900 mV. The limits of detection (3 S/N) and limits of quantification (10 S/N) of the studied compounds were evaluated using dilution method. The proposed method was validated according to standard guidelines and optimization of various experimental parameters and chromatographic conditions was carried out. The optimized and validated HPLC-ECD method was successfully applied for the determination of the abovementioned compounds in human plasma and erythrocytes. The method will be quite suitable for the determination of plasma and erythrocyte profile of ascorbic acid and aminothiols in oxidative stress and other basic research studies.