层板金属离子不同的钴基双氢氧化物制备及其电化学性能

通过调变层板中的三价金属离子制备了层板金属离子不同的钴基双氢氧化物(LDHs),X-射线衍射(XRD)和傅里叶变换红外(FTIR)测试表明,层板中金属离子的变化对LDHs的物理结构有较大影响。电化学性能比较表明,三价金属离子的改变对材料的有效工作电位窗口和大电流稳定性及循环容量保持率均有很大影响。由于二价与三价金属离子在电化学过程中的作用不同,Co-AlLDHs在1A·g-1的电流密度下比容量达到447F·g-1;Co-InLDHs与Co-CrLDHs则具有很好的循环稳定性和电容性质。     

Mixed-ligand chelate extraction of trivalent lanthanides and actinides with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 and dihexyl-N,N-diethylcarbamoylmethyl phosphonate

Mixed-ligand chelate extraction of trivalent lanthanides such as La, Eu and Lu and a trivalent actinide, Am into xylene with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP) and dihexyl-N,N-diethylcarbamoylmethylphosphonate (CMP) has been studied by tracertechniques. These trivalent metal ions are found to be extracted from 0.01 mol/dm³ chloroacetate buffer solutions as M(PMBP)₃·HPMBP type self adducts with HPMBP alone and in the presence of CMP as M(PMBP)₃·CMP (where M=La, Eu, Lu and Am) into the organic phase. The equilibrium constants of the above species are deduced by non-linear regression analysis. The synergistic constants of trivalent lanthanides do not increase monotonically with atomic number but have a maximum at Eu and that of Am was found to lie between that of La and Eu.     

Luminescent double-decker type guanine octets with trivalent lanthanide cations: in situ self-assembling and stability evaluation in homogeneous organic media

Silylated guanine formed luminescent double-decker type octet complexes with trivalent lanthanide cations (lanthanide cation : guanine = 1:8) in organic media, while a deaminated guanine derivative gave only 1:2 complexes. The octet formation was evidenced by characteristic UV/Vis absorption changes, CSI-TOF MS and ¹H NMR spectra. The octet with Tb³⁺ showed intense green luminescence with a long lifetime by photo-excitation of the guanine chromophore. The trivalent lanthanie cations stabilized the octets more effectively than common mono- and divalent metal cations.     

一种罗丹明衍生物的合成及其对三价金属离子(Fe~(3+)、Cr~(3+)和Al~(3+))的识别

三价金属离子(Cr~(3+)、Fe~(3+)和Al~(3+))与人体健康密切相关。目前,检测Cr~(3+)、Fe~(3+)和Al~(3+)需要采用不同的荧光探针,增加了检测成本和检测时间。发展能够同时检测Cr~(3+)、Fe~(3+)和Al~(3+)的高灵敏度和强抗干扰能力的荧光探针具有非常重要的意义。本文以罗丹明B为原料,合成和表征了一种罗丹明类荧光增强型探针(P),并研究了其光谱性质。研究表明,在V(甲醇)∶V(水)=9∶1体系中对三价金属离子Fe~(3+)、Cr~(3+)和Al~(3+)具有较高的选择性,不受其它二价金属离子及一价金属离子的影响,抗干扰能力强。同时,探针P对三价金属离子具有较高的灵敏度,对Cr~(3+)、Al~(3+)和Fe~(3+)的检测限分别为3.0×10~(-4)、2.7×10~(-4)和1.0×10~(-4)mol/L,表明其可用于Cr~(3+)、Al~(3+)和Fe~(3+)的检测。     

Synthesis and structure of 1-(1,3,2-dioxaphospholan-2-yl)- and 1-(4-methyl-1,3,2-dioxaphosphinan-2-yl)azepan-2-one copper diacetate complexes

Complexation of trivalent phosphorus amides with copper acetate leads to compounds possessing catalytic activity in oligomerization reactions [1].     

Collapse of Four-Arm Stars Polyelectrolyte Brushes Under An Electric Field in the Presence of Trivalent Salt Coions

Langevin dynamics simulations were conducted to study the collapse of grafted partially charged 4-arm star chains onto the oppositely charged grafting electrode in the presence of trivalent salt coions. Simulation results reveal that the average charge fraction of the grafted star chains and the salt concentration play critical roles in the competitive adsorption of charged monomers and trivalent salt coions onto the oppositely charged electrode. For grafted star chains with relatively high charge fraction, charged monomers are the dominant species collapsing on the oppositely charged electrode with the emergence of charge reversal on the grafting electrode. At a low charge fraction such that the total amount of charges on a grafted star molecule is comparable to that of a trivalent salt coion, trivalent salt coions absorb more strongly onto the electrode than grafted stars even at very low salt concentration. It is found that at relatively low charge fraction of star chains, the addition of trivalent salt coions does not lead to charge overcompensation of the surface charges on the grafting electrode. The stretching of star brushes under an electric field in the presence of trivalent salt coions was also briefly investigated.     

Ensuring complete absence of Ce(IV) and measurement of the stability constant of the fluoride complex of Ce(III)

Literature survey revealed a wide variation in the measured stability constant values of the aqueous fluoride complexes of trivalent cerium. This could be due to inadequate care for full conversion and maintenance of the oxidation state of cerium to trivalent state. In the present work quinhydrone has been used to ensure complete absence of Ce(IV) and the stability constant of CeF(2+) in 1 M NaClO(4) has been measured potentiometrically using a fluoride ion selective electrode. Log beta(1) obtained in this work was 2.936+/-0.024 and fitted well with the general trend of stability constants of the lanthanide (rare earths) fluorides in aqueous solution.     

Complexation Studies of Bidentate Heterocyclic N-Donor Ligands with Nd(III) and Am(III)

A new bidentate nitrogen donor complexing agent that combines pyridine and triazole functional groups, 2-((4-phenyl-1H-1,2,3-triazol-1-yl)methyl)pyridine (PTMP), has been synthesized. The strength of its complexes with trivalent americium (Am³⁺) and neodymium (Nd³⁺) in anhydrous methanol has been evaluated using spectrophotometric techniques. The purpose of this investigation is to assess this ligand (as representative of a class of similarly structured species) as a possible model compound for the challenging separation of trivalent actinides from lanthanides. This separation, important in the development of advanced nuclear fuel cycles, is best achieved through the agency of multidentate chelating agents containing some number of nitrogen or sulfur donor groups. To evaluate the relative strength of the bidentate complexes, the derived constants are compared to those of the same metal ions with 2,2′-bipyridyl (bipy), 1,10-phenanthroline (phen), and 2-pyridin-2-yl-1H-benzimidazole (PBIm). At issue is the relative affinity of the triazole moiety for trivalent f element ions. For all ligands, the derived stability constants are higher for Am³⁺ than Nd³⁺. In the case of Am³⁺ complexes with phen and PBIm, the presence of 1:2 (AmL₂) species is indicated. Possible separations are suggested based on the relative stability and stoichiometry of the Am³⁺ and Nd³⁺ complexes. It can be noted that the 1,2,3-triazolyl group imparts a potentially useful selectivity for trivalent actinides (An(III)) over trivalent lanthanides (Ln(III)), though the attainment of higher complex stoichiometries in actinide compared with lanthanide complexes may be an important driver for developing successful separations.     

Sorption Characteristics of Radioeuropium on Bentonite and Kaolinite

The factors affecting the sorption of radioeuropium(III) by bentonite and kaolinite were studied with the aim to assess the important factors which should be included in modeling of radioeuropium(III) migration in soils and sediments. Europium(III) is an analogue of trivalent actinides. The distribution coefficients of radioeuropium for sorption on bentonite and kaolinite from aqueous solutions were determined by using the batch method, and it was found that they were sensitive to the loading, the pH, the humic substance and the sorption direction. Thus, these sorption characteristics of radioeuropium on bentonite and kaolinite were found to be different from those of radiocobalt¹, and the mathematical modeling of trivalent lanthanides and actinides migration will be more complicated than that of radiocobalt. It is improbable that the migration modeling with a constant distribution coefficient will be successful in the case of trivalent lanthanides and actinides.     

1-Chlorophospholenes containing trivalent phosphorus

Conclusions Some phospholene P-chlorides, containing trivalent phosphorus, were obtained by the reduction of 1-thioxo-1-chlorophospholenes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, p. 181, January, 1972.     

Enhancement of near-IR emission by bromine substitution in lanthanide complexes with 2-carboxamide-8-hydroxyquinoline

Three novel 2-carboxamide-8-hydroxyquinoline derivatives wrap helically around trivalent lanthanide ions to form monometallic 3 : 1 complexes possessing strong NIR emission.     

Reaction of N-chloromethyldiethylamine,N-chloromethylbenzamide,N-chloromethylphthalimide with amides of trivalent phosphorus acids

Conclusions In the series of N-chloromethylphthalimide, N-chloromethylbenzamide, N-chloromethyldiethylamine, in reactions with amides of trivalent phosphorus acids, the contribution of the reaction at the phosphorus atom increases with increase in the polarity of the C-Cl bond. N-Chloromethylphthalimide, whose C-Cl bond is least polar in this series, reacts with hexaethyltriamidophosphite and diethylamidodiphenylphosphinite reacts at the N and P atoms to form the corresponding quasiphosphonium salts and acid chlorides of trivalent phosphorus acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 173–178, January, 1985.     

Attempts to Rationalize the Chemical Reactivity of the 1–3 Dipolar Species Obtained when a Phosphite Reacts with Activated Ethylenic or Acetylenic Ketones or Esters

Abstract

- Addition of trivalent phosphorus compounds with α, β ethylenic ketones and esters leads to examples of prototropy or cyclisation or rearrangement with ring expansion from 5 to 7 atoms.

When trivalent phosphorus compounds react with acetylenic ketones and esters, the 1, 3 dipolar species can be trapped with an electrophilic reagent (aldehydes or the original acetylenic compound) or a protic reagent (alcohol, acid, amide, phenol, etc…) Ylides, phosphoranes, spirophos-phoranes and phospholes can be obtained.     

双功能钛硅分子筛的合成、表征及催化性能

以四丙基溴化铵为模板剂, 硅溶胶为硅源, 正丁胺为碱源, 采用水热合成的方法, 将三价离子(Al³⁺, B³⁺或Fe³⁺)和Ti⁴⁺同时引入到MFI型分子筛的骨架, 得到同时具有氧化和酸催化活性的双功能钛硅分子筛M-TS-1(M=Al, B或Fe). 通过X射线粉末衍射、傅里叶变换红外光谱、紫外-可见漫反射光谱、氨程序升温脱附、电感耦合等离子体原子发射光谱和N₂吸附-脱附等温线手段对样品进行了表征. 结果表明, 三价离子的引入, 提高了TS-1的酸强度和酸量. 采用乙烯选择氧化为探针反应考察了M-TS-1的催化性能. 结果表明, Al-TS-1和B-TS-1在乙烯环氧化及后续的开环溶剂解反应中表现出较高的催化性能, H₂O₂的转化率在95%以上, H₂O₂的利用率大于90%, 乙二醇和乙二醇单甲醚的总收率可达10%以上.     

Unusual Transformations of 2-Cyanoacrylates in Reactions with Trivalent Phosphorus Compounds

Abstract

Cyanoacrylates 1 have existed for 40 years, but up till ¹ only polymerization processes, effected by various nucleophiles, including trivalent phosphorus compounds, have been known. We have shown that under established conditions 1 (aR=Me, b R=Et) reacts with trivalent phosphorus compounds not only via the anionic polymerization pathway, but depending on the structure, it forms stable adducts2,4 or 5.     

Electrochemical oxidation of californium in carbonae solutions

The electrolysis of trivalent californium, terbium and praseodimium in 2M K₂CO₃ solutions at pH 13.2 results in a partial oxidation of the trivalent ions to a higher oxidation state. Absorption spectra of Cf/III/ in 1M HCLO₄ and in 2M K₂O₃ and that of oxidized californium in carbonate solution have been recorded. Incomplete oxidation is accounted to a reducing species generated at high anode potentials.     

Complexes macrocycliques des lanthanides: Stabilité et comportement électrochimique dans le méthanol et le carbonate de propylène

Macrocyclic Complexes of Lanthanides: Stability and Electrochemical Behaviour in Methanol and Propylene Carbonate The stabilities of the 1:1 complexes of the trivalent lanthanides with the diazapolyoxamacrocycles (2.1.) and (2.2.1.) in anhydrous methanol and propylene carbonate have been determined at 25°, by competitive potentiometric methods using H⁺ or Ag⁺ as auxiliary cations, with Et₄NClO₄ as supporting-electrolyte. Additional data are also reported for the crown ethers 15C5 and 18C6 in propylene carbonate. It is shown that the diazapolyoxamacrocycles are much stronger complexing agents for trivalent lanthanides than macrocyclic polyethers, and that the bicyclic (2.2.1.) cryptates are more stable than the monocyclic (2.1.) complexes. With increasing atomic number of the lanthanides, the stability increases with diazapolyoxamacrocycles and decreases with cyclic polyethers. The electrochemical reduction of the trivalent samarium and europium cryptates has been investigated by polarography on a dropping Hg-electrode, in water and methanol. In both solvating solvents, the +2 oxidation states of the cations are stabilized by complexation.     

Thermodynamics of thiocyanate complexes of trivalent actinides and lanthanides

The thermodynamic parameters ΔF, ΔH and ΔS of the complexes of Cm(III), C(III) and Tm(III) with the SCN^? ion have been determined at 30°C in ammonium ion medium of unit ionic strength by the temperature variation method. It has been concluded that both the thiocyanate complexes of trivalent actinides and lanthanides are predominantly inner-sphere type. The higher stability of the second complexes of trivalent actinides is reflected either in the enthalpy or the entropy change depending on the degree of hydration of the trivalent actinide ions. The implications of the greater free energy change for PuSCN²⁺ as compared with other trivalent actinide or lanthanide first thiocyanate complexes are discussed.     

Mechanistic study on the effect of PEG molecules in a trivalent chromium electrodeposition process

The mechanism of chromium metal deposition from a trivalent chromium bath containing formic acid and polyethylene glycol 1000 (PEG) was studied on an electrochemical quartz crystal microbalance (EQCM), electrospray ionization mass spectrometry (ESI-MS) and a technique for measuring pH on the cathode surface. Reactions of PEG molecules with trivalent chromium ions and their influence on the plating process of trivalent chromium were investigated. EQCM studies at low trivalent chromium ion concentrations show that chromium electrodeposition occurs via the formation of an adsorption layer on the electrode surface, which is called a cathodic film. Cathodic films hinder the penetration of ions from bulk solution to the cathode surface. In the inner portion of the cathodic film and at the cathode surface, intermediate complexes were formed during the deposition process. ESI-MS revealed that the PEG molecules were stable in a trivalent chromium bath containing potassium formate. During electroplating, the PEG molecules decreased the reductive current of hydrogen compared with solutions without PEG; an effect that was also observed due to the pH on the electrode surface. PEG plays a decisive role in the formation of intermediate compounds during electrodeposition.     

Extraction behavior of trivalent lanthanoids and yttrium with bis (2,4,4-trimethylpentyl)octylphosphine oxide

The extraction behavior of yttrium and trivalent lanthanoids has been investigated from thiocyanate solutions using bis(2,4,4-trimethylpentyl)octylphosphine oxide (CYANEX 925) in xylene as an extractant by tracer techniques. The results demonstrate that these trivalent metal ions are extracted as M(SCN)₃•3CYANEX 925. The equalibrium constants of the extracted complexes have been deduced by non-linear regression analysis. The extraction behavior of trivalent lanthanoids and yttrium was found to be ambiguous since the distribution ratios of these metal ions are nonmonotinic function of atomic number (La<Y<Pm<Tm<Ho<Eu<Yb<Lu). The separation factors between these trivalent metal ions have been calculated and compared with commercially important extraction systems like tributylphosphate (TBP), trioctylphosphine oxide (TOPO), octy(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and di-2-ethylhexyl phosphoric acid (DEHPA). The possibilities for separating yttrium from trivalent lanthanoids has also been discussed.