共查询到20条相似文献,搜索用时 343 毫秒
1.
H. B. Yang E. H. Lee J. K. Lim D. Y. Chung K. W. Kim 《Journal of Radioanalytical and Nuclear Chemistry》2009,280(3):495-502
The extraction of Am(III) and Eu(III) using a γ-pre-irradiated N,N′-dimethyl-N,N′-dibutyltetradecyl malonamide (DMDBTDMA)
modified with N,N′-dihexyloctanamide (DHOA) in n-dodecane (NDD) at 4.5M HNO3 has been studied as a function of the absorbed dose up to 2×106 Gray. The distribution ratios of Am(III) and Eu(III) were almost constant until a dose of 1×105 Gray and then they decreased gradually up to a dose of 2×106 Gray. The decrease of the distribution ratios of Am(III) and Eu(III) are due to the decreasing concentration of the DMDBTDMA
by a γ-pre-irradiation and these results were supported by a determination of the DMDBTDMA concentration with a gas chromatography
method. The distribution ratios of Am(III), Eu(III), Ce, Nd and Y with γ-pre-irradiated (DMDBTDMA-DHOA)/NDD have also been
studied as a function of the nitric acid concentration and the extraction temperature. 相似文献
2.
3.
4.
A series of fifteen complexes of the type [Fe(RRNCS2)3] with symmetric (R=R=n- C6H13, n-C8H17, CH2–CH=;CH2, C6H5, C6H11 and C6H5CH2), unsymmetric (R = CH3; R = n-C4H9, C6H11, C6H5 and R = C2H5; R = n-C4H9, C6H11, C6H5 and i-C3H7) and ring substituents (RNR=pyrrolidyl and piperidyl) have been synthesized and their magnetic moments and Mössbauer spectra recorded from room temperature (RT) to liquid nitrogen temperature (LNT). Room temperature Mössbauer spectra of all the complexes exhibit an asymmetric doublet, which could be resolved into two doublets, each corresponding to low and high spin states in equilibrium. The crystal structure of tris(N, N-diallyldithiocarbamato)iron(III) shows it to be monoclinic with trigonally distorted octahedral geometry and space group C2/c. Fe–S stretching vibrations in the far i.r. region also show equilibria, HS LS. Depending on the nature of the alkyl group substituent, variable temperature magnetic moment and Mössbauer spectral studies, all the complexes may be divided into three groups; high spin complexes exhibiting spin-crossover (6A1g 2T2g), high spin complexes exhibiting spin transition (6A1g 4T1g) and intermediate spin complexes showing spin transition (4A1g 2T2g). On the basis of areas of the two doublets corresponding to high and low spin states, their percent contributions were calculated. Furthermore, magnetic moments of the equilibrium mixture calculated on the basis of respective areas compare well with the experimentally determined eff values. EQ values for both high and low spin states show linear decrease with increasing temperature. 相似文献
5.
Novel complexing processes by CoIII-dithiooxamide, CoIII-N,N-diphenylthiooxamide and CoIII-N,N-diphenyldithiooxamide systems, with a cobalt(III)hexacyanoferrate(II) gelatin-immobilized matrix in contact with an aqueous solution of the corresponding ligand, have been observed and analyzed. Under the specific conditions described, four different coordination compounds are formed in the CoIII-dithiooxamide system, three of which are insoluble in water, whereas in each of the CoIII-N,N-diphenylthiooxamide and CoIII-N,N-diphenylthiooxamide systems, three water-insoluble coordination compounds are formed. In solution or the solid phase, formation of only one complex is observed, in each of the systems studied. 相似文献
6.
《Journal of Inorganic and Nuclear Chemistry》1978,40(2):253-256
Under carefully controlled experimental conditions and with the maintenance of completely anhydrous systems, crystalline lanthanide complexes with nitrogen-donor ligands N,N′-dimethylethylenediamine (dmed) and N,N,N′,N′-tetramethylethylenediamine (tmed) have been isolated. Stoichiometric compositions of the products are Ln(dmed)2Cl3 (Ln = Sm, Er, Yb), Ln(dmed)2(NO3)3 (Ln = Pr, Sm), Gd(dmed)(NO3)3, Ln(tmed)Cl3 (Ln = La, Pr, Nd, Sm, Ho, Er) and Ln(tmd)(NO3)3·xCH3CN (Ln = Nd, Er, Ho; x = 0, 1). Calorimetric studies indicate that the dmed complexes do not form in a stepwise fashion in acetonitrile, but rather that higher-order species form in solution. 相似文献
7.
Summary An electrochemical study on N,N-Propylene-bis-(salicylideneiminato) Mn(III) was performed using cyclic voltammetry with convolution-deconvolution and digital simulation in phosphate buffer solutions ofpH values ranging from 5–9.5 at a hanging mercury drop electrode (HMDE). The reduction pathway of the investigated complex shows that a moderately fast transfer of one electron is followed by a very fast chemical reaction (E
q
C
irr scheme). The electrochemical parameters have been determined experimentally andvia digital simulation experiments.
Elektrochemische Untersuchung von N,N-Propylen-bis-(salicylideniminato)-Mn(III) in Phosphatpufferlösungen
Zusammenfassung N,N-Propylen-bis-(salicylideniminato)-Mn(III) wurde in Phosphatpufferlösungen mitpH-Werten im Bereich von 5–9.5 an einer Quecksilbertrofelektrode (HMDE) mittels cyclischer Voltammetrie (Konvolution-Dekonvolution, digitale Simulation) elektrochemisch untersucht. Ein mäßig schneller Transfer eines Elektrons wird von einer sehr schnellen chemischen Reaktion gefolgt (E q C irr-Schema). Die elektrochemischen Parameter wurden experimentell und durch Simulations-experimente bestimmt.相似文献
8.
《Journal of Inorganic and Nuclear Chemistry》1976,28(3):443-445
The complexes of N,N′-didodecildithiooxamide (L): CoL3(ClO4)3, NiL2X2 (X = Cl, Br, I, ClO4, HSO4), CuL2X2 (X = ClO4, HSO4) and CuLX2 (X = Cl, Br) were prepared. The cobalt and nickel complexes are diamagnetic, with octahedral and planar coordination respectively. The copper complexes are paramagnetic with normal magnetic moments corresponding to a tetragonal coordination. The i.r. and far i.r. spectra are discussed. 相似文献
9.
Kanthimathi Mookandi Unni Nair Balachandran Ramasami Thirumalachari Jeyakanthan Jeyaraman Velmurugan Devadasan 《Transition Metal Chemistry》2000,25(2):145-149
A new chromium(III) Schiff base complex, [Cr(3-methoxysalen)(H2O)2]ClO4, where salen=N,N-ethylenebis- (salicylideneimine), has been synthesized and characterized by spectroscopic techniques. Single crystal X-ray data reveals that the complex assumes a trans-diaquo structure with formulation [Cr(C18H22N2O6)]ClO4 but, unlike in Cr (salen)(H2O)2
+, the two trans-water molecules are equidistant from CrIII. The effect of the substituent on the phenyl ring in respect of redox reactivity has been investigated. The kinetics of the oxidation of [Cr(Schiff base)- (H2O)2]ClO4, where Schiff base=salen, (1) and 3-OMe-salen, (2) by PhOI has been studied. The bimolecular rate constant for the formation of the O=Crv Schiff base in case of (2) was four times faster than that of (1). The introduction of the OMe group substituent on the phenyl ring influences not only the structure and crystal packing, but also the reactivity of the complex and the electronic environment around the metal ion. 相似文献
10.
《Journal of Coordination Chemistry》2012,65(1-2):19-27
Abstract The reactions between As(III), tartaric acid (H2T)and DCTA were investigated polarographically. The conditional stability constants of As(III)-complexes at a given pH-value and variable ligand concentration were calculated from the change of the limiting currents. The optimum conditions for calculating stability constants from the current were also discussed. It was found that DCTA (H4L)formed the complex [As(OH)2HL]2- whose overall formation constant was lgβ111=(20.67 ±0.09)atμ=0.1 and t°- (25.0±0.2)°C, whereas the complex between As(III) and H2T was [As(OH)2T]? with an overall stability constant 1gβ 101= 6.62 ±0.14 at μ=0.1 and t°= (25 ± 0.2)°C. 相似文献
11.
M. R. Malik T. Rüffer H. Lang A. A. Isab S. Ali S. Ahmad H. Stoeckli-Evans 《Journal of Structural Chemistry》2013,54(4):810-814
A cadmium(II) complex dicyanidobis(N,N′-dimethylthiourea-S) cadmium(II) [Cd(Dmtu)2(CN)2] (1) is prepared and its structure in the solid state is determined by single crystal X-ray structural analysis. The cadmium(II) ion is four-coordinate having a distorted tetrahedral geometry composed of two cyanide C atoms and two thione S atoms of N,N′-dimethylthiourea (dmtu). The molecular structure is stabilized by intermolecular N-H…N(CN) hydrogen bonding interactions that lead to a 3D network structure. The complex was also characterized by IR and NMR spectroscopy. 相似文献
12.
A. S. Gordetsov L. N. Martynova S. V. Zimina E. M. Moseeva S. E. Skobeleva N. V. Kulagina 《Russian Chemical Bulletin》1994,43(3):458-460
N,N-Bis(trimethylsilyl)dicyandiamide was prepared for the first time by the reaction of dicyandiamide with hexamethyldisilazane in boiling tetrahydrofuran. Thermal transformations of this compound were studied by DTA. The novel compound may be used in the synthesis of bis(trimethylsilyl)carbodiimide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 498–500, March, 1994. 相似文献
13.
Russian Journal of General Chemistry - The first representatives of silicon-containing azocarboxamides, N,N′-bis(silylmethyl) azodicarboxamides, were synthesized by the reaction of... 相似文献
14.
M. M. El-Dessouky N. Hafez M. T. Haridi M. S. Yaccoub 《Journal of Radioanalytical and Nuclear Chemistry》1992,157(2):393-399
The publication describes chelation studies of cerium(III) with 1,2-bis(-aminoethoxy)-ethane N,N,N,N-sodium sulfonate triacetic acid (ASTA). The results showed the effectiveness of ASTA as a chelating agent by molar ratio, continuous variation and slope ratio methods. Stable 11 complex was formed at pH from 4 to 8. Aqueous solutions of the chelate of different mole ratios at pH and 7.5 were irradiated by -radiation with different doses. The results show that a decrease of absorbance with increasing absorbed dose was obtained in the dose range studied. A proposed radiolytic mechanism is discussed. The degradation of ligand was due to OH radical. 相似文献
15.
《Journal of Coordination Chemistry》2012,65(2):251-257
A novel one-dimensional polynuclear complex, tris(trifluoroacetylacetonato)(4,4'-bipyridyl- N , N '-dioxido)lathanum(III), was synthesized and characterized by elemental analysis and IR spectroscopy. X-ray structure analysis revealed that the complex has an infinite one-dimensional polynuclear structure with the 4,4'-bipyridyl- N , N '-dioxide as a bridge. La(III) is coordinated to eight oxygen atoms, six from three trifluoroacetylacetonate anions and two from two 4,4'-bipyridyl- N , N '-dioxide molecules to form a slightly distorted square antiprismatic coordination polyhedron. The coordination moiety was linked through 4,4'-bipyridyl- N , N '-dioxide forming a one-dimensional chain. 相似文献
16.
Heterobinuclear copper(II)–lanthanoid(III) complexes bridged by N,N′-oxamidobis(benzoato)cuprate(II)
Eight new -oxamido-bridged copper(II)–lanthanoid(III) heterobinuclear complexes described by the overall formula Cu(obbz)Ln(Me-phen)2NO3 (Ln = Y, La, Nd, Eu, Gd, Tb, Ho, Er), where obbz denotes the oxamidobis(benzoato) and Me-phen represents 5-methyl-1,10-phenanthroline (Me-phen), have been synthesized and characterized by the elemental analyses, spectroscopic (i.r., u.v., e.s.r.) studies, magnetic moments (at room temperature) and by molar conductivity measurements. The temperature dependence of the magnetic susceptibility of Cu(obbz)Gd(Me-phen)2NO3 has also been measured over the 4.2 300 K range. The least-squares fit of the experimental susceptibilities based on the spin Hamiltonian operator, = –2 J
1 ·
2, yielded J = + 2.18 cm–1. The observed GdIII–CuII coupling is ferromagnetic. A plausible mechanism for a ferromagnetic coupling between GdIII–CuII is discussed in terms of spin-polarization. 相似文献
17.
Yasunori Yamada Daishin Koori Kengo Mori Yuuki Oshikawa 《Journal of Coordination Chemistry》2016,69(24):3735-3744
The reaction of N,N′-bis(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)-R-1,2-propanediamine (R-bbppnH2) with LnCl3?6H2O (Ln: Lu, Yb) stereoselectively gave an optically active complex, [LnCl(R-bbppn)], which crystallizes in the acentric space group of P212121. The central lutetium(III) is coordinated by two oxygens from two phenolates, four nitrogens from two pyridines, and one bidentate propanediamine of R-bbppn2?, one chloride to form a seven-coordinate distorted pentagonal bipyramidal geometry. Although two optical isomers, ΔΛΔ and ΛΔΛ, are possible for such a structure, the absolute configuration of the complex is stereoselectively unified to ΔΛΔ. The coordinated chloride of the complex is readily replaced by other ligands, and hence the reaction with thiocyanate results in formation of another seven-coordinate complex, [Ln(NCS)(R-bbppn)]. 相似文献
18.
A new CrIII complex, viz. trans-[Cr(naphprn)(H2O)2]ClO4·2H2O, (1) {naphprn=N,N-trimethylenebis(naphthylideneimine)} has been synthesized and characterized. Aquo ligand substitution of (
1
) by the azide ligand gave rise to trans-[Cr(naphprn)(N3)(H2O)], (
2
). Irradiation of (
2) in DMF gave nitrido(naphprn)chromium(V) (
3
). Solutions of (
3
) showed e.p.r. spectra at room temperature (g
iso=1.9865). The i.r. spectra showed disappearance of a band at 2067cm–1 showing the breakdown of NN and appearance of a new band at 1074cm–1which is assigned to the Cr14N, stretching frequency indicating the formation of a nitrido chromium(V) complex, (
3). The u.v.–vis. spectrum of complex (
3
) exhibited a d–d band maximum at 553nm (=120M–1cm–1). The rate of formation of (
2
) was found to be 5.0×10–3M–1s–1 in an aqueous acidic medium at [CrIII]=0.5×10–3M; [N3
–]=0.01–0.15M; [H+]=0.001M and I=0.2M (LiClO4). The rate of photo-decomposition of (
2
) to give rise to (
3
) was found to be 0.15×10–3s–1 in DMF. 相似文献
19.
Maria Grazia Maglione Carla Minarini Riccardo Miscioscia Giuseppe Nenna Emma Romanelli Paolo Tassini 《Macromolecular Symposia》2007,247(1):311-317
In this paper we present and discuss experimental results to evaluate performances and aging behaviour of two Hole Transporting Material (HTM), TPD and NPD, in Organic Light Emitting Device (OLED) with structure: ITO/HTM/Alq3/Al. For each of these HTMs, devices with several thicknesses have been built, to measure and emphasize behaviours of material-geometry combinations. Electro-optical properties have been measured to estimate and compare brightness, power efficiency and aging decays. 相似文献
20.
Actinide(III), (IV), (V) and (VI) ions were extracted by N,N-dimethyl-N,N-dihexyl-3-oxapentanediamide (DMDHOPDA) and thenoyltrifluoroacetone (HTTA). The extraction behaviors suggested the possibility of the mutual separation, and the convenient separation method of actinide ions (III), (IV), (V) and (VI) without reducing and oxidizing agents was studied. Th(IV) was extracted from the aqueous phase by HTTA (5 mM in toluene) in the first step. The Am(III) and U(VI) ions can be extracted by 1 and 20 mM DMDHOPDA in toluene, and the Np(V) ion can be extracted into nitrobenzene with 100 mM DMDHOPDA in the last step. The residual activities in the aqueous phase were much lower than the initial activities. These activities in the fractions were confirmed by the gamma- and the alpha-spectrometry. The one-through and rough separation is advanced, and in case of the fine isolation of actinide elements, each fraction should be purified in more detail. 相似文献