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61.
Guo Zhijun Niu Yanning Zhang Weiguang Tan Minyu 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(2):331-337
N,N,N',N',N',N'-Hexaethyl-2,2′,2'-(nitrilotrisethyleneoxy-2-benzyloxy)tris(acetamide) (L3) has been prepared and characterized
by using IR, 1H NMR and positive-ion FAB mass spectra. The extraction of Th4+ and UO2
2+ with N,N,N',N',N',N'-hexaethyl-2,2',2'- (nitrilo-trisethyleneoxy)tris(acetamide) (L1), N,N,N',N',N',N'-hexaisopropyl-2,2',2'-(nitrilotrisethyleneoxy)tris(acetamide)
(L2), and L3 was studied at 20±1 °C as a function of diluent, concentration of free extractant in organic phase and concentration
of picrate in aqueous phase. It was found that the extracting powers of L1 and L2 for Th4+ are almost identical. The extracting power of L2 for UO22+ was slightly higher than that of L1. The difference in terminal
groups (ethyl or isopropyl) of the extractants (L1 and L2) with same backbone has a little effect on the extracting power
for both Th4+ and UO22+. The extracting powers of L3 for both Th4+ and UO22+ were larger than those of L1 and L2. The extractants
(L1 and L3) having the same terminal group (ethyl) with different backbones have obviously different extracting powers for
Th4+ or UO22+. The extracting powers of all three extractants L1, L2, and L3 for Th4+ were larger than those for UO22+. The
compositions of extracted species in organic phase were predominantly ThL(Pic)3NO3 and UO2L(Pic)NO3, respectively (L denotes
L1, L2 and L3).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
62.
现场表面拉曼光谱研究Fe-Mo合金诱导共沉积 总被引:1,自引:0,他引:1
现场表面拉曼光谱结果显示,在0.2mol·L-1Na2MoO4,pH=4.0的溶液中,电位正于0.5V(vsSCE)时只观察到多钼酸盐的拉曼峰(940、880和450cm-1).负于-0.5V时,出现中心位于730cm-1的宽峰.同时电极表面有蓝色膜生成.表明混合氧化态(MO(Ⅳ),MO(Ⅴ))氧化膜的形成.730cm-1的峰在-1.9V时仍然存在,说明氧化膜没有被进一步还原.在钼酸钠溶液中同时含有0.1mol·L-1FeSO4和0.2mol·L-1柠檬酸时,中间态氧化膜的拉曼峰的中心移到740cm-1.且峰强度随着电位从-1.3V负移到-1.9V而逐渐减弱并最终消失.电极表面沉积层呈银白色,说明由于Fe2 的存在,钼的中间态氧化膜的结构发生了变化,能够被进一步还原形成Fe-Mo合金,表现出诱导共沉积的特征. 相似文献
63.
Besma Lajmi Mourad Hidouri Mongi Ben Amara 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):i156-i158
The crystal structure of tripotassium pentairon hexaphosphate has been determined by single‐crystal X‐ray diffraction. The structure contains one Fe atom on a center of symmetry, one K, two Fe and two P atoms on twofold axes, and one Fe, two P and one K atom in general positions. The K3Fe5(PO4)6 structure consists of a complex three‐dimensional framework of corner‐sharing between iron polyhedra, and corner‐ and edge‐sharing between PO4 tetrahedra and iron polyhedra (FeO5 and FeO6). This linkage between iron and phosphorus forms intersecting channels containing the K atoms. 相似文献
64.
A two-dimensional network compound [Ce(DMF)4(H2O)][α-BW12O40]·H2O·(HDMA)2 (HDMA = protoned dimethylamine, DMF = N,N-dimethylformamide) was synthesized from α-H5BW12O40·nH2O, Ce(NO3)3·6H2O and DMF and characterized by IR, UV spectra and TG-DTA. The result of the X-ray single crystal diffraction indicates that
the crystal is monoclinic, space group P21/n, with unit cell dimensional: a = 1.1983(3), b = 2.4216(5), c = 1.9517(4) nm, β = 92.91(3)°, Z = 4, R
1 = 0.07710, wR
2 = 0.1416. Structural analysis indicates that every [Ce(DMF)4(H2O)]3+ building block is surrounded by three adjacent [α-BW12O40]5− polyanions, meanwhile, every [α-BW12O40]5− polyanion interconnects with three neighboring [Ce(DMF)4(H2O)]3+ subunits, by making use of which two-dimensional network structure can be constructed. The result of thermogravimetric analysis
manifests that the title compound has two-stage weight loss and the decomposition temperature of the title polyanionic framework
is 560°C. The electrochemical analysis shows the title polyanion has three-step redox processes in the pH = 4–7 media. 相似文献
65.
Two synthetic routes to a novel class of sterically overcrowded alkenes, bithioxanthylidene crown ethers 1, are described. The 1H spin-lattice relaxation times (T1) of the crown ethers as well as those of the corresponding complexes with Li+, Na+, K+, Rb+ and Cs+ in CDCl3 were measured and the results were interpreted in terms of complexation affinities. 相似文献
66.
Conway B Hevia E Kennedy AR Mulvey RE Weatherstone S 《Dalton transactions (Cambridge, England : 2003)》2005,(8):1532-1544
Synthesised either by an unusual tert-butyl metathesis between tert-butyllithium and a n,s-butylmagnesium amide or by reaction of an alkyl Grignard reagent and a sodium amide, five tert-butylmagnesium amides, Bu(t)MgDBA (5)(DBA=dibenzylamide), Bu(t)MgDA (6)(DA=diisopropylamide), Bu(t)MgHMDS (7)(HMDS=1,1,1,3,3,3-hexamethyldisilazide), Bu(t)MgTMP (8)(TMP=2,2,6,6-tetramethylpiperidide) and Bu(t)MgNCy2 (9)(cy=cyclohexyl) have been isolated as crystalline solids. All five amides have been characterised by X-ray crystallography and solution NMR spectroscopic studies. The former studies reveal a common dimeric molecular structure with amido bridges in a planar (MgN)2 ring and terminal Bu(t) ligands on the Mg atoms. Also described is the dodecameric primary amide [Bu(n)MgN(H)Dipp]12 (10a) and its monomeric solvate Bu(n)MgN(H)Dipp.TMEDA (10b)(Dipp=2,6-diisopropylphenyl; TMEDA=N,N,N',N'-tetramethylethylenediamine). The crystal structures of the oxo-insertion products Bu(t)MgOBu(t).THF (11), Bu(t)Mg(mu-OBu(t))(mu-TMP)MgTMP (12) and Mg(OBu(n))HMDS.solv [solv=THF (13a) or Et2O (13b)], made fortuitously during the course of this work, are also presented. 相似文献
67.
68.
Nonlinear and nonequilibrium electrophoresis of spherical particles of radius a is shown to be possible when the solid surface allows field or current penetration. At low particle Peclet numbers, transient capacitative charging occurs until the surface polarization completely screens the external field. For a DC applied field [see text], the resulting electrokinetic velocity reaches Dukhin's maximum value of [formula: see text], where [see text] and mu are the liquid permittivity and viscosity. At high Peclet numbers, electroosmotic convection of the electroneutral bulk stops the transient charging before complete field-line exclusion. For an ion-selective and conducting spherical granule, the polarization is then determined by the steady-state Ohmic current driven by the penetrated external field. The high-Peclet electrokinetic velocity is lower, diffusivity-dependent and scales as [see text]. 相似文献
69.
Leita BA Moubaraki B Murray KS Smith JP Cashion JD 《Chemical communications (Cambridge, England)》2004,(2):156-157
The dinuclear iron(II) complex [(pypzH)(NCSe)Fe([micro sign]-pypz)(2)Fe(NCSe)(pypzH)].2H(2)O displays a single, sharp spin crossover transition between the [HS-HS] and [LS-LS] states and is structurally characterised above and below the T(1/2)= 225 K value 相似文献
70.
Crystal structures of new nitronyl nitroxide derivatives 1, 2 and 3 were determined with X‐ray diffraction analysis: 1, monoclinic, C2/c, a = 1.2404(5) nm, b = 0.9730(5) um, c = 2.7049(10) ran, β = 98.189(15)°, V = 3.2315(24) nm3, Z = 8; 2, or‐thorhombic, Pbca, a = 0.61262(2) nm, b = 1.11426(6) nm, c = 2.30543(13) nm, V = 1.57373(13) nm3, Z = 4; 3, monoclinic, P2(1)/n, a=0.64253(4) nm, b=2.55003(17) nm, c = 1.15497(6) nm, β = 95.000(3)°, V = 1.8852(2) nm3, Z = 4. Their magnetic properties were measured with SQUID and analyzed based on their crystal structures with simple singlet‐triplet, modified one dimensional antiferromagnetic chain and modified singlet‐triplet models respectively: 1, J/kb= ?2.5 K; 2, J/kb = 7.8 K, θ = 2.8 K; 3, J/kb = ?0.96 K, θ = 0.21 K. 相似文献