Tetraazadibora[3, 3]paracyclophane

Starting from the para‐phenylenediamine derivative HN(SiMe₃)‐C₆H₄‐NH(SiMe₃), a lithiation and subsequent borylation give [(MeO)₂B]N(SiMe₃)‐C₆H₄‐N(SiMe₃)[B(OMe)₂] ( 1 ), the hydridation of which yields Li₂[(H₃B)N(SiMe₃)‐C₆H₄‐N(SiMe₃)(BH₃)] ( 2 ). Applying ZrCl₄ upon 2 initiates a condensation to give the title compound [‐N(SiMe₃)‐p‐C₆H₄‐N(SiMe₃)‐BH‐]₂, a hetero[3, 3]paracyclophane with two N‐B‐N chains that connect the para‐phenylene units. The product 3 crystallizes in the orthorhombic space group P2₁2₁2₁.     

Heterobimetallische Komplexe mit Chelatliganden aus mehrzähnigen Aminen und 1,1-Bis(diphenylphosphan)ethen

Heterobimetallic Complexes with Chelate Ligands from Multidentate Amines and 1,1-Bis(diphenylphosphine)ethene By an addition reaction of bidentate amines Me₂N(CH₂)_nNH₂ (n = 2, as-4C2N; 3, as-5C2N) and vinylidene derivatives with an activated double bond CH₂ = C(PPh₂)₂M(CO)₄ (M = Cr, Mo, W) were synthesized in dichlormethane unsymmetrical chelate ligands of the type as-4C2N (or as-5C2N)PPM(CO)₄. They gave with divalent salts M′Y₂ (Y = ac, M′ = Cu, Ni. Y = Cl, M′ = Zn, Cd, Hg) the coloured bimetallic complexes M′Y(as-4C2N) (or as-5C2N)PPM(CO)₄ which were characterized by means of IR-, UV/VIS spectroscopic and ¹H, ¹³C and ³¹P NMR measurements. The molecular structures of the complexes Cuac₂(as-5C2N)PPCr(CO)₄, I and that of CdCl₂(as-4C2N)PPCr(CO)₄, II , were acertained by results of single crystal X-ray determinations. In the crystals of I—II , the coordination polyhedron of each chromium(0) central atom containing two phosphorous donor atoms in a four-membered chelate ring and four terminal CO ligands is octahedrally distorted. This coordination sphere is connected at the carbon ring atom via a methylen chain group (spacer) with the bidentate amine ligand, which has a secondary and a tertiary nitrogen donor atom. Both nitrogen atoms are coordinated with the Cuac₂ under formation of a new kind of [4 + 2]-coordination in a trischelate complex. The six-membered diamine chelat ring in I has a chair-like conformation. The chromium-cadmium complex II is dimer from which the Cd central atoms obtain the rare coordination number of five. The related five-membered diamine chelate ring has δ conformation.     

Thermal decomposition of ammonium vanadyl oxalate supported on various oxides

The thermal decomposition of ammonium vanadyl oxalate supported on La₂O₃, MgO, SiO₂, Al₂O₃, ZrO₂, TiO₂, SAPO-5, and ZSM-5 oxides in a dynamic atmosphere of dry air was compared by thermal gravimetric analysis (TG) and differential thermal analysis (DTA). The calcined catalysts were characterized by X-ray diffractometry (XRD). The TG and DTA results demonstrate that the surface acid-base properties of the oxides play a significant role in the decomposition behaviour of the supported ammonium vanadyl oxalate, i.e. the basic oxides exhibit an endothermic effect and the acidic oxides show an exothermic effect. Two mechanisms are suggested for thermal decomposition of ammonium vanadyl oxalate on basic and acidic oxides, respectively. After transformation of the ammonium vanadyl oxalate to vanadia, subsequent rearrangement of the vanadia on the surface of the supports was also observed. During the thermal treatment or calcination in air, solid state reactions of vanadia with the surface of oxides such as La₂O₃, ZrO₂ and TiO₂ took place to form new phases.     

Gas chromatography of halogens

Summary The semi-empirical theory on the retention volume in gas chromatography recently developed by some experiments, was found to require partial correction. It was newly refined and summarized. Overall experimental checking was performed by the use of Cl₂, Br₂, and I₂.

---

Gas-Chromatographie von Halogenen

Zusammenfassung Die halbempirische Theorie über das Retentionsvolumen in der Gas-Chromatographie, die kürzlich an Hand einiger Versuche entwickelt wurde, erforderte eine teilweise Korrektur. Sie wurde verbessert und zusammenfassend dargestellt. Kontrollversuche wurden mit Hilfe von Chlor, Brom und Jod durchgeführt.

     

白刺与枸杞中微量元素含量的对比研究

采用ICP-AES法对生长在同一区域内的白刺与枸杞根茎中的8种微量元素的含量进行了分析测定。结果表明,两种植物根茎中8种元素含量丰富,并且差异明显,为以后的开发利用提供了基础数据。     

人体微量元素平衡与健康饮食

综述了人体微量元素平衡与健康饮食的关系。微量元素参与机体内的各种代谢,在维持人的生命活动中发挥着重要的作用。正确理解微量元素的生理功能,树立科学的平衡营养观,是引导人们自觉地实现多样化饮食、促进健康长寿的关键。     

Group 6 tetracarbonyl complexes of N-[(2-pyridyl)methyliden]-α (or β)-aminonaphthalene: Spectral characterization,electrochemistry, solvatochromism and photophysical studies

A new series of group 6 carbonyl complexes of N-[(2-pyridyl)methyliden]-α (or β)-aminonaphthalene (α/β-NaiPy) are described in this work. The complexes are formulated as cis-[M(CO)₄(α/β-NaiPy)] by elemental, mass and other spectroscopic data. The complexes show emission spectra at room temperature and their quantum yield lies between 0.4 and 0.5. All the complexes exhibit negative solvatochromism. Cyclic voltammetry shows metal centred oxidation and ligand reductions.     

主族元素取代的11-钨铜杂多配合物的合成、表征及性质研究

合成了ⅡA,ⅣA,ⅤA族元素为取代原子的3个系列钨铜杂多配合物.经ICP,TG曲线确定其化学式为K8[CuZ(OH2)W11O39].xH2O和K17,18[Z′(CuW11O39)2].xH2O(Z=Mg,Ca;Z′=Sr,Ba,Sn,Pb,Sb,Bi).通过TG-DTA,IR,XRD,XPS,183W-NMR等手段对合成配合物结构进行了表征,并对其进行了讨论.结果表明,新配合物具有典型的Keggin结构,且主族元素进入到配合物的骨架中.由于新配合物中CuⅡ具有顺磁性,导致XPS,183W-NMR的测试结果表现出特殊性;用循环伏安法测定了新配合物的电化学性质,表明均为可逆氧化还原过程,还对导电性和热稳定性进行了研究.     

聚乙撑二氧噻吩膜在氧化态的充电过程及电容研究

In this paper, the chronoamperometry was used to study the charging processes of polyethylenedioxythiophene (PEDOT) modified electrodes in the potential range where PEDOT was in the oxidized state. The results show that the charging behaviors of the PEDOT films are well agreed with the exhausted finite diffusion model. The dependence of the capacitance values of the films on potential and concentration of solution was also studied in this potential range.