Nitridsulfidchloride der Lanthanide: III. Synthese und Kristallstruktur von Pr5N3S2Cl2

Nitride Sulfide Chlorides of the Lanthanides. III. Synthesis and Crystal Structure of Pr₅N₃S₂Cl₂ By reacting praseodymium with sulfur, sodium azide and praseodymium trichloride in sealed, evacuated silica tubes (850°C, 7 d), the nitride sulfide chloride Pr₅N₃S₂Cl₂ is obtained in case of a 4:2:1:1 molar ratio of the reactants (Pr:S:NaN₃:PrCl₃). A slight excess of trichloride or the addition of NaCl as a flux supports the yield of brownish red, rod-shaped transparent crystals which prove to be stable against hydrolysis. The crystal structure (monoclinic, C2/m (no. 12), a = 1540.2(1), b = 400.92(3), c = 1656.3(1) pm, β = 101.24(1)°, Z = 4, R = 0.039, R_w = 0.028) was determined by means of X-ray single crystal data. Thus five crystallographically different cations (Pr³⁺) are present which with three distinct kinds of nitride anions (N^3?) build up two types of translationally commensurate chains from interconnected [NPr₄] tetrahedra. With an additional edge per “chain-link” in chain I, two single chains [NPr_3/3^ePr_1/1^t]³⁺ (?[NPr₂]³⁺) of cis-edge connected [NPr₄] tetrahedra (known from the Sm₄N₂S₃-type structure) are condensed into the double chain [(N1){(Pr1)_(2+2)/(2+2)^e,e(Pr2)_(2+1)/(2+1)^e,v}(N2)(Pr3)_1/1^t]³⁺ (?[N₂Pr₃]³⁺). Chain II consists of two single chains [NPr_2/2^vPr_2/1^t] ⁶⁺ (?[NPr₃]⁶⁺) of vertex-connected [NPr₄] tetrahedra (known from the Sm₃NS₃-type structure), which are condensed to the double chain [(N3)(Pr4)_2/2^e(Pr5)_2/2^v]³⁺ (?[NPr₂]³⁺) via an additional edge per “chain-link” too. Both types of chains are bundled along [010] like a closest packing of rods. Four crystallographically different but by X-ray diffraction indistinguishable anions S^2? and Cl^? hold both cationic double chains together and also adjust the charge balance in a molar ratio of 1 : 1.     

Theoretical study of the reactions of the 1Σ+ ground state of MS+ (M = Sc,Y, and La) with oxygen‐transfer reagent MS+ + CO → ScO+ + CS in the gas phase

The reaction mechanisms of the ¹Σ⁺ ground state of MS⁺ (M = Sc, Y, and La) with oxygen‐transfer reagent MS⁺ + CO → MO⁺ + CS in the gas phase has been proposed and investigated by ab initio methods with the 6‐31G* basis set for nonmetal atoms and the effective core potentials of Lanl2dz for the metal atoms. A carbon migration from oxygen atom to sulfur atom via a four‐center transition state is involved on the reaction potential surface. The activation energies of the reactions are 34.0, 24.1, and 36.7 kcal/mol relative to their corresponding reactants and the reaction heats are 15.7, 18.6, and 18.0 kcal/mol (respectively, for M = Sc, Y, and La) at the MP4 (SDTQ)/6‐31G*//MP2/6‐31G* level plus zero‐point energy, which indicates that the cationic yttrium sulfide is more favorable for this type of reaction. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003     

Rate constant of free electron-hole recombination in thin cadmium sulfide films

The transient decay kinetics of electrons generated in thin cadmium sulfide films by short laser pulses was studied by the microwave photoconductivity method (9 and 36 GHz) at 295 K. The films were prepared by the pulverization method from thiocarbamide coordination compounds. At the high light intensity I ₀ > 10¹⁴ photon cm^–2 per pulse, the decay kinetics of photoelectrons corresponded to a reaction of the second order. Analysis of the kinetic data made it possible to determine the rate constant of recombination of free electrons and holes: k ₃ 2(±1)·10^–13 cm³ s^–1.     

溶胶-凝胶型陶瓷碳硫离子选择性电极的研制

将溶胶-凝胶技术与印制电极技术相结合制作了复合陶瓷碳硫离子选择性电极。对溶胶-凝胶形成条件和印刷浆液的组成进行了试验,电极制作过程包括电极膜基质制备、溶胶、凝胶型型陶瓷碳硫离子敏感膜制备、敏感膜在基质上的固定化三步。对电极的参数进行了测试。该电极稳定性、重现性好,响应快。应用于实际和模拟样品分析,取得满意效果。采用该法制备离子选择性电极具有简易、价廉、易集成化等特点,适合于制作一次性使用的离子选择性电极。     

20^#碳钢表面室温电解渗硫层的减摩性能

采用MPX-200型摩擦摩损试验机考察了碳氮共渗及室温电解硫化处理后20^#碳钢的摩擦学性能,探讨了在干摩擦条件下载荷、渗硫处理时间和滑动摩擦时间对渗硫层摩擦系数的影响。结果表明：室温电解渗硫层具有明显的减摩作用,并在一定程度上提高了材料表面的抗磨性能。表面层的X射线光电子能谱分析结果表明,其主要成分为硫化铁（FeS）。     

硫化条件对加氢裂化催化剂金属硫化度的影响

采用高压连续微反装置及X -射线光电子能谱 (ESCA)等仪器 ,考察了不同硫化条件对加氢裂化催化剂中活性组分的存在状态及价态分布的影响。研究表明 :在整个硫化温度区间内 ,2 30℃时催化剂硫化速率较快 ,在此温度下需要恒温硫化 ,较佳恒温时间为 3h ,压力 (>4 5MPa)对催化剂硫化度有一定的影响 ,不同组成的催化剂其硫化性能也不同。在催化剂硫化过程中 ,W5 是硫化过程中的一种中间过渡产物 ,随硫化温度的升高可转化为W4 。     

聚丙烯腈活性炭纤维对硫化氢的常温吸附

聚丙烯腈活性炭纤维（PAN-ACF）对硫化氢（H2S）有比其他活性炭材料更强的吸附能力。H2S在PAN-ACF上的吸附是一个兼具物理吸附特征的化学吸附、催化转化过程。其化学吸附位主要位于微孔表面。吸附过程为：H2S分子首先被物理吸附进入微孔空间,而后在微孔表面的化学吸附位上进行包含电子转移的化学吸附、催化氧化,在炭表面产生相对稳定的化学结构。     

Ionization potentials of non-metal monosulfides. Conjugation in radical cations containing Group IV elements

The first vertical ionization potentialsI(n_s) of 69 monosulfides XSY (X, Y=H, Hal, organic, or heteroorganic substituent) are related to the inductive σ_I resonance (σ _R ⁺ ) and polarizability (σ_α) constants of the substituents by dependences of theI(n_S)=a+bΣσ_I+bΣσ_R+bΣσ_α type. TheI(n_s) values are also affected by hyperconjugation which increases on going from XSH to XSY (Y≠H) compounds. The first calculations of the σ _R ⁺ parameters characterizing the conjugation of Si-, Ge-, Sn-, and Pb-containing substituents with the S^.+ radical cation center are reported. The reasons for weakening of resonance donor properties of heteroorganic substituents of the +M-type in the systems studied as compared to those of the same substituents in the corresponding aromatic radical cations are considered. Translated fromIzvestiya Akademii Nauk. Seriya Khmicheskaya, No. 1, pp. 25–31, January, 2000.     

基于半导体纳米线/锥形微光纤探针的被动式近场光学扫描成像

本文结合近场扫描结构和纳米线-微光纤耦合技术,提出了一种基于硫化镉纳米线/锥形微光纤探针结构的被动近场光学扫描成像系统.该系统采用被动式纳米探针,保留了纳米探针对样品表面反射光的强约束优势.其理论收集效率为4.65‰,相比于传统的金属镀膜近场探针收集效率提高了一个数量级,可有效地提高扫描探针对样品形貌信息的检测能力;而后通过硫化镉纳米线与微光纤之间高效的倏逝场耦合,将检测的光强信号传输到远场进行光电探测,最终实现对目标样品形貌的分析成像,其样品宽度测量误差在7.28%以内.该系统不需要外部激发光路,利用显微镜自身光源进行远场照明,被动扫描探针仅作为样品表面反射光的被动收集系统.本文基于半导体纳米线/锥形微光纤探针的被动式近场光学扫描成像方案,可有效地降低探针的制备难度和目标光场的检测难度,简化扫描成像的结构,为近场光学扫描显微系统之后的发展提供新的思路.     

Formation and Crystal Structure of 4,4'-Oxybis(2,6-bis(dimethylamino)-4H-1,3,5,4-thiadiazaphosphinine 4-Oxide)

Abstract

The reaction of P₄S₁₀ with dimethyl cyanamide as solvent yields a complex mixture of products, from which the new compound 4,4′-oxybis(2,6-bis(dimethylamino)-4H-1,3,5,4-thiadiazaphosphinine 4-oxide) (1) was isolated. In this pyrophosphate derivative, the phosphorus atoms are part of the, otherwise rarely encountered, 1,3,5,4-thiadiaza-phosphinine ring. The molecular structure of the new compound was elucidated by single-crystal X-ray diffraction, showing an almost planar thiadiazaphosphinine ring and a cis-like arrangement of the heterocycles at the two phosphorus atoms.