Highly efficient separation of actinides from lanthanides by a phenanthroline-derived bis-triazine ligand

The synthesis, lanthanide complexation, and solvent ex- traction of actinide(III) and lanthanide(III) radiotracers from nitric acid solutions by a phenanthroline-derived quadridentate bis-triazine ligand are described. The ligand separates Am(III) and Cm(III) from the lanthanides with remarkably high efficiency, high selectivity, and fast extraction kinetics compared to its 2,2'-bipyridine counterpart. Structures of the 1:2 bis-complexes of the ligand with Eu(III) and Yb(III) were elucidated by X-ray crystallography and force field calculations, respec-tively. The Eu(III) bis-complex is the first 1:2 bis-complex of a quadridentate bis-triazine ligand to be characterized by crystallography. The faster rates of extraction were verified by kinetics measurements using the rotating membrane cell technique in several diluents. The improved kinetics of metal ion extraction are related to the higher surface activity of the ligand at the phase interface. The improvement in the ligand's properties on replacing the bipyridine unit with a phenanthroline unit far exceeds what was anticipated based on ligand design alone

Complexation of lanthanides, actinides and transition metal cations with a 6-(1,2,4-triazin-3-yl)-2,2’:6’,2’’-terpyridine ligand: implications for actinide(III) /lanthanide(III) partitioning

The quadridentate N-heterocyclic ligand 6-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2’:6’,2’’-terpyridine (CyMe4-hemi-BTBP) has been synthesized and its interactions with Am(III), U(VI), Ln(III) and some transition metal cations have been evaluated by X-ray crystallographic analysis, Am(III)/Eu(III) solvent extraction experiments, UV absorption spectrophotometry, NMR studies and ESI-MS. Structures of the 1:1 complexes with Eu(III), Ce(III) and the linear uranyl (UO22+) ion were obtained by X-ray crystallographic analysis, and showed similar coordination behavior to related BTBP complexes. In methanol, the stability constants of the Ln(III) complexes are slightly lower than those of the analogous quadridentate bis-triazine BTBP ligands, while the stability constant for the Yb(III) complex is higher. 1H NMR titrations and ESI-MS with lanthanide nitrates showed that the ligand forms only 1:1 complexes with Eu(III), Ce(III) and Yb(III), while both 1:1 and 1:2 complexes were formed with La(III) and Y(III) in acetonitrile. A mixture of isomeric chiral 2:2 helical complexes was formed with Cu(I), with a slight preference (1.4:1) for a single directional isomer. In contrast, a 1:1 complex was observed with the larger Ag(I) ion. The ligand was unable to extract Am(III) or Eu(III) from nitric acid solutions into 1-octanol, except in the presence of a synergist at low acidity. The results show that the presence of two outer 1,2,4-triazine rings is required for the efficient extraction and separation of An(III) from Ln(III) by quadridentate N-donor ligand

Biological Effects of a De Novo Designed Myxoma Virus Peptide Analogue: Evaluation of Cytotoxicity on Tumor Cells

Not availabl

Interaction of 6,6′′-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2′:6′,2′′-terpyridine (CyMe4-BTTP) with some trivalent ions such as lanthanide(iii) ions and americium(iii)

The new ligand 6,6 ''-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)2,2':6 ',2 ''-terpyridine (CyMe4-BTTP) has been synthesized in 4 steps from 2,2':6',2 ''-terpyridine. Detailed NMR and mass spectrometry studies indicate that the ligand forms 1 : 2 complexes with lanthanide(III) perchlorates where the aliphatic rings are conformationally constrained whereas 1 : 1 complexes are formed with lanthanide(III) nitrates where the rings are conformationally mobile. An optimized structure of the 1 : 2 solution complex with Yb(III) was obtained from the relative magnitude of the induced paramagnetic shifts. X-Ray crystallographic structures of the ligand and of its 1 : 1 complex with Y(III) were also obtained. The NMR and mass spectra of [Pd(CyMe4-BTTP)](n)(2n+) are consistent with a dinuclear double helical structure (n = 2). In the absence of a phase-modifier, CyMe4-BTTP in n-octanol showed a maximum distribution coefficient of Am(III) of 0.039 (+/-20%) and a maximum separation factor of Am(III) over Eu(III) of 12.0 from nitric acid. The metal(III) cations are extracted as the 1 : 1 complex from nitric acid. The generally low distribution coefficients observed compared with the BTBPs arise because the 1 : 1 complex of CyMe4-BTTP is considerably less hydrophobic than the 1 : 2 complexes formed by the BTBPs. In M(BTTP)(3+) complexes, there is a competition between the nitrate ions and the ligand for the complexation of the metal

Synthesis and evaluation of novel water-soluble ligands for the complexation of metals during the partitioning of actinides

Different types of water-soluble ligands were synthesized and their capability was evaluated by solvent extraction studies to complex trivalent actinides and suppress their extraction by a strong lipophilic ligand, such as TODGA. The back extraction efficiency of hydrophilic diglycolamide (DGA) derivatives with a varying number of ethylene glycol groups, or containing sodium acetate moieties on the amidic nitrogen shows a decrease in back-extraction efficiency with increasing number of ethylene glycol units on the amidic nitrogen at various pH values of the aqueous phase. Among the P-S donating ligands only the ligand with a malonamide backbone exhibits a high reverse extraction efficiency, although, with no selectivity for americium. Within the water-soluble tripodal ligands, i.e. the amide derivatives of nitrilotriacid with N,N-dimethyl and N, N-bis(hydroxyethyl) moieties, the first one shows a pronounced selectivity for Am(III) over Eu(III), with a maximum separation factor of 11.1, while the latter one more efficiently complexes the radionuclides in the aqueous phase with a maximum separation factor of 5. Isothermal microcalorimetry experiments of the complexation of Eu(III) by a selected series of ligands confirm the observed trend in the back extraction properties

Influence of technical factors on chopping corn harvested for silage

The investigations aimed at the explanation of the effect of working unit technical parameters of forage harvester equipped with a chopping unit on the course and effects of maize grain chopping. The performed stationary experiments showed that chopping efficiency was significantly influenced by the type of edge elements installed on the knives, working clearance between bottom plate and circumferential surface of edge elements and by the number of knives and speed of the rotor. However, it was found that the value of chopping index was not affected by the direction and shape of bottom plate notches, the type of knife guiding plate or intensity of maize stream fed to the harvester. Among all the considered forage harvester configurations, the best results were found for the combination including the bottom plate with bars, the smooth guiding plate, the working clearance of 8 mm at the inlet and 2 mm at the outlet, 10 knives, and rotor speed of 1000·min⁻¹. The maize chopping efficiency at the moisture content of 44 and 67% amounted to 90-95 and 98-100%, respectively.Celem badań było wyjaśnienie wpływu parametrów technicznych zespołów roboczych sieczkarni z toporowym zespołem rozdrabniającym na przebieg i efekt rozdrabniania ziaren kukurydzy. Przeprowadzone badania stacjonarne wykazały, że rodzaj elementów krawędziowych instalowanych na końcach noży, wielkość szczeliny roboczej między płytką denną a powierzchnią obwodową elementów krawędziowych, liczba noży i prędkość obrotowa tarczy nożowej są czynnikami istotnie wpływającymi na efektywność rozdrabniania ziaren kukurydzy. Natomiast kierunek i kształt karbów płytki dennej, typ listwy prowadzącej mocowanej do noży i natężenie strumienia masy kukurydzy wprowadzanej do sieczkarni nie różnicowały wskaźnika rozdrabniania. Spośród wszystkich rozpatrywanych układów pracy sieczkarni najlepszy okazał się wariant z kombinacją, w której zastosowano płytkę denną z prętami, krawędź z listwą cepową, gładką listwę prowadząca, szczelinę roboczą na wlocie 8 mm i na wylocie 2 mm, 10 noży i 1000 obr.·min⁻¹ tarczy nożowej. Podczas cięcia kukurydzy o wilgotności 44 i 67% efektywność rozdrabniania ziaren wynosiła odpowiednio 90-95 i 98-100%