ICP-AES 法测定 RZnAl5RE 合金中的镧、铈、铁、铝、铅、镉

采用ＩＣＰ－ＡＥＳ测定了ＲＺｎＡｌ５ＲＥ合金中的Ｌａ、Ｃｅ、Ｆ３、Ａｌ、Ｐｂ、ＣＤ元素含量。考察了基体及无机酸浓度对６种元素线强度的影响。选择了仪器工作条件,检出限在０．０３～１．００μｇ／Ｌ之间,加标回收率为９３％～１０８％,相对标准偏差小于１２．６８％（ｎ＝１０）。     

ICP-MS法测定鼠脊髓液中超痕量镧、铈、镨和钕

采用ＮＨＯ３＋ＨＣｌＯ４混合酸溶样,感耦等离子体－质谱（ＩＣＰ－ＭＳ）直接测定鼠脊髓液中Ｌａ、Ｃｅ、Ｐｒ和Ｎｄ,对等离子体质谱测定条件进行了最佳化选择。选用铼（Ｒｅ）内标可补偿基体影响和仪器漂移。方法检出限为７．６－２０．３ｎｇ／Ｌ,加标试验回收率为９４％－１０２％,相对标准偏差（ＲＳＤ）为２．１％－３．７％。     

镧对V2O5/γ-Al2O3催化剂在异丁烷脱氢中活性的影响

V2O5／γ-Al2O3是用于异丁烷脱氢的新型催化剂，引入适量的镧不仅可改善活性组分的分散度，提高催化脱氢活性，而且还增强了催化剂的抗积炭能力，通过FTIR，BET，TG，TPR和TEM等手段研究了镧对催化剂性能的影响。     

微波辐射下固体超强酸SO_4~(2-)/TiO_2/La~(3+)催化合成没食子酸正丁酯

没食子酸正丁酯为白色或淡褐黄色的结晶粉末,无臭,稍有苦味;难溶于水,易溶于乙醇,是一种油溶性的抗氧化剂,常作为食品稳定剂、感光材料添加剂等[1 ] 。没食子酸正丁酯可由没食子酸和正丁醇在硫酸催化下直接合成。硫酸催化活性高,价格低,但对设备腐蚀严重,副反应多,产率低,反应时间长,后处理比较困难。近年来有采用十二烷基苯磺酸、固体超强酸[2 ,4] 等作为替代硫酸的催化剂。固体超强酸的应用研究进展较快,已从单一型向复合型发展。本文在微波辐射下用固体超强酸SO2 -4 /TiO2 /La3+为催化剂由没食子酸与正丁醇合成没食子酸正丁酯,考察了反…     

Binäre Lanthan‐Stannide mit Sn:La‐Verhältnissen nahe 1:1 – Synthesen,Kristallstrukturen, Chemische Bindung

Four binary lanthanum stannides close to the 1:1 ratio of Sn:La were synthesized from mixtures of the elements. The structures of the compounds have been determined by means of single‐crystal X‐ray data. The low temperature (α) form of LaSn (CrB‐type, orthorhombic, space group Cmcm, a = 476.33(6), b = 1191.1(2), c = 440.89(6) pm, Z = 4, R1 = 0.0247), crystallizes with the CrB‐type. The structure exhibits planar tin zigzag chains with a Sn–Sn bond length of 299.1 pm. In contrast to the electron precise Zintl compounds of the alkaline earth elements, additional La–Sn bonding contributions become apparent from the results of band structure calculations. In the somewhat tin‐richer region, the new compound La₃Sn₄ (orthorhombic, space group Cmcm, a = 451.45(4), b = 1190.44(9), c = 1583.8(2) pm, Z = 4, R1 = 0.0674), crystallizing with the Er₃Ge₄ structure type, exhibits Sn₃ segments of the zigzag chains of α‐LaSn together with a further Sn atom in a square planar Sn coordination with increased Sn–Sn bond lengths. In the Lanthanum‐richer region, La₁₁Sn₁₀ (tetragonal, space group I4/mmm, a = 1208.98(5), c = 1816.60(9) pm, Z = 4, R1 = 0.0325) forms the undistorted tetragonal Ho₁₁Ge₁₀ structure type. Its structure, which contains isolated Sn atoms, [Sn₂] dumbbells and planar [Sn₄] rings is related to the high temperature (β) form of LaSn. The structure of β‐LaSn (space group Cmmm, a = 1766.97(6), b = 1768.28(5), c = 1194.32(3) pm, Z = 60, R1 = 0.0453), which forms a singular structure type, can be derived from that of La₁₁Sn₁₀ by the removal of thin slabs. Due to the different stacking of the remaining layers, planar [Sn₄] chain segments and linear [Sn–Sn–Sn] anions are formed as additional structural elements. The chemical bonding (Sn–Sn covalent bonding, Sn–La contributions) is discussed on the basis of the simple Zintl concept and the results of FP‐LAPW calculations (density of states, band structure, valence electron densities and electron localization function).     

A Further Extension of Pnictide Oxide Chemistry – Synthesis and Structure of La2AuP2O

The phosphide oxide La₂AuP₂O was synthesized from lanthanum filings, dried La₂O₃, gold pieces, and ground red phosphorus in the ideal 1.33:0.33:1:2 ratio in an evacuated silica tube at 1473 K. Small single crystals were obtained by recrystallization in a NaCl/KCl flux. The structure was determined on the basis of single‐crystal X‐ray diffractometer data: new type, C2/m, a = 1537.3(3), b = 427.39(8), c = 1009.2(2) pm, β = 131.02(1) °, wR₂ = 0.046, 1102 F² values, 38 variables. La₂AuP₂O contains two striking structural motifs: The oxygen atoms are located in La₄ tetrahedra. The latter are cis‐edge‐shared forming polymeric cationic [La₂O]⁴⁺ chains. These cationic units are separated and charge‐balanced by [AuP₂]^4– polyanions which have monovalent gold in distorted trigonal planar phosphorus coordination. Two crystallographically independent phosphorus sites occur in the polyanion, i.e. isolated P^3– besides dumb‐bells P₂^4– (P2–P2 223 pm). La₂AuP₂O, which crystallizes in the form of ruby red transparent crystals, is an electron precise phosphide oxide (4La³⁺)(2Au⁺)(2P^3–)(P₂^4–)(2O^2–).     

Electrochemical Detection of Schistosoma Japonicum Antibody Using Biocatalytic Deposition

Abstract

An ultrasensitive electrochemical immunoassay based on biocatalytic deposition has been proposed for the detection of Schistosoma japonicum antibody (SjAb) in infected rabbit serum. Schistosoma japonicum antigen (SjAg) was immobilized on the gold electrode surface via glutaraldehyde crosslink and then incubated with infected rabbit serum containing SjAb; finally, the goat anti-rabbit IgG labeled with alkaline phosphatase was sandwiched to form the immunocomplex on the gold electrode surface. The alkaline phosphatase converted nonelectroactive substrate into the reducing agent and the latter, in turn, reduced metal ions to form electroactive metallic product on the electrode surface. Linear sweep voltammetry (LSV) was used to quantify the amount of the deposited silver and give the analytical signal for SjAb. Assay conditions such as the antigen concentration and enzymatic silver deposition time were optimized. The electrochemical immunosensor was able to realize a reliable determination of SjAb in the dilution range from 1:5000 to 1:100 with a detection limit of 1:6457 of dilution ratio. The feasibility of the proposed immunosensor for possible clinical applications was also investigated by analyzing real serum samples.     

COMPLEXES OF MOLYBDENUM(V) AND LANTHANUM(III) WITH 2′,2″′-(2,6-PYRIDINEDIYLDIETHYLIDENE)-DIOXAMOHYDRAZIDE (H2DAPSOX)

Abstract

In a template synthesis from ethanolic solution of MoOCl₃, 2,6-diacetylpyridine (dap), and semioxamazide (sox), in the molar ratio 1:1:2, a dimeric molybdenum(V) complex [Mo₂O₂(H₂dapsox)₂]Cl₆ · 4H₂O (where H₂dapsox = 2′,2″′-(2,6-pyridinediyldiethylidenedioxa-mohydrazide) was obtained. In a similar reaction, starting from La(NO₃)₃ · 6H₂O, the complex [La(H₂dapsox)(NO₃) _x ](NO₃)_3-x · 1/2EtOH (x = 1,2), having coordination number 9, was obtained. In the latter complex two NO₃ Groups were bidentately coordinated in the solid state, but only one in the solution.

Besides [Mo₂O₂(TPP)₂] (TPP = tetraphenylporphyrin), the molybdenum(V) complex [Mo₂O₂ (H₂dapsox)₂]Cl₆ · 4H₂O is the only other known example of a dimeric μ-oxodimolybdenum(V) species that is paramagnetic (μ = 0.95 BM). One of the Mo atoms has pentagonal bipyramidal coordination, and the other pentagonal pyramidal coordination. In aqueous solution a rare example of a pentagonal pyramidal ion [MoO(dapsox)]⁺ is presumably present. Solution EPR spectra (at 77K) cannot be related to either of the two known types of Mo(V) species based on the extent of g anisotropy. The substances also were characterized by IR and electronic spectroscopy, and by thermal analysis.     

Tris(Trifluoroacetylacetonato)(4,4′-bipyridyl-N,N′-dioxido)Lanthanum(III)∶ A One-dimensional Polynuclear Complex

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.     

Hydrothermal Synthesis and Crystal Structure of [（CH3CH2）4N]4[（La12（OH）12MoO29）],A Novel Cluster Compound with a MoO5 Hexahedron Center surrounded by La—O Octahedron

IntroductionRecently,the molecular designs of polyox-ometalates( POM) with basic oxometal clusterbuilding blocks are of great interest[1,2 ] . Hy-drothermal synthesis,with the characteristic ofone- pot reaction,provides a convenient method toobtain novel structures of POM compounds[3— 6] . Inthe Ln/Mo/O system ( Ln=rare earth) ,somecompounds containing La and Mo elements havebeen reported[7— 17] . However,these compoundshave all been synthesized under the highly restrict-ed synthetic co…