CrIII-Phthalocyaninate: Darstellung,Eigenschaften und Kristallstruktur von l-Bis(triphenylphosphin)iminium-trans-di(nitrito(O))phthalocyaninato(2–)-chromat(III)

Cr^III Phthalocyaninates: Synthesis, Properties, and Crystal Structure of l-Bis(triphenylphosphine)iminium trans-Di(nitrito(O))phthalocyaninato(2–)chromate(III) [Cr(H₂O)₂Pc^2?]I_x reacts with excess (PNP)NO₂ in dimethylformamide to yield less soluble greenblack l-bis(triphenylphosphine)iminium trans-di(nitrito(O))phthalocyaninato(2–)chromate(III), ^l(PNP)^trans[Cr(ONO)₂Pc^2?], which crystallizes in the triclinic space group P1 (No. 2) with Z = 2. The Cr atom is in the center of the Pc^2? ligand and the two nitrite ions are monodentate O-coordinated in a mutually trans arrangement to the Cr atom. The Cr? O and Cr? N_iso bond distances are 1.9898(14) und 1.981(2) Å, respectively. The geometric data of the coordinated nitrite ion are: d(N? O) = 1.307(2) Å; d(N? O) = 1.205(2) Å; ?(O? N? O) = 113.7(2)°; ?(Cr? O? N) = 116.85(12)°. The non-bonding O atoms are trans to the Cr atom. The Pc^2? ligand is slightly saddled. Three weak spin-allowed trip-quartet(TQ) transitions (in 10³ cm^?1): TQ1 (8.20) < TQ2 (11.3) < TQ3 (20.33) and the characteristic π-π* transitions of the Pc^2? ligand: B (14.68) < Q₁ (27.1) < Q₂ (29.0) < N (35.4) are observed in the UV-VIS-NIR spectrum. Prominent luminescence spectra are obtained by excitation within the TQ1 region, in which the spin-forbidden trip-sextet transition at 7376 cm^?1 dominates at low temperatures (T < 50 K). The vibrational spectra are discussed. In coincidence of the excitation lines with TQ3, v_s(Cr? O) at 378 cm^?1 is selectively resonance Raman (RR) enhanced. v_as(Cr? O) is observed in the FIR spectrum at 391 cm^?1. The following internal vibrations (in cm^?1) of the nitrito ligand are in the MIR spectrum: v_as(N? O)/1447 > v_as(N? O)/1018/1029 > δ(O? N? O)/828 and in the RR-spectrum: v_s(N? O)/1410 > v_s(N? O)/952, the last followed by three overtones.     

Thermal behaviour of benzenesulfenamides and of their chromium carbonyl complexes

Benzenesulfenamides with the formula R-S-N-(R)₂ (R=C₆H₅ andR=NC₄H₈O, C₇H₇ and C₆H₁₁) and their chromium carbonyl complexes were studied by means of TG and mass spectrometric methods. The thermal behaviour of the compounds the stabilities of free sulfenamides are lower than those observed for the corresponding chromium carbonyl complexes. Combined thermogravimetry — mass spectrometry results suggest that the fragmentation mechanism of the carbonyl complexes involves cleavage of the Cr-S and Cr-CO bonds while that of sulfenamide depends mainly on the dissociation rates of the NR₂ groups.This work was partially supported by the Departamento técnico de Investigation of the Universidad de Chile, Grant Q3280/9324.     

烟酸铬(Ⅲ)的配位结构与生物活性关系

合成了2种新型吡啶-3-羧酸(烟酸)铬(Ⅲ)螯合物,通过元素分析、热分析、红外光谱和电子光谱证明烟酸作为双齿配位体,形成具有3个六员环的螯合物Cr(Nic)3和具有2个六员环与2个H2O单体的混型配合物[Cr(Nic)2(H2O)2]Cl。通过使用效能等试验表明,在猪饲料中添加不同配位结构的烟酸铬均有明显提高饲料利用率、促进生长和显著提高机体对葡萄糖的清除率等作用。试验还表明,双齿配位的烟酸铬具有较高的生物活性、无毒、饲用后在肌体内无残留,作为饲料添加剂具有广阔的应用前景。     

In Situ Study of the Surface Oxidation of FeCr Alloys Using Grazing Incidence X‐ray Absorption Spectroscopy (GIXAS)

The surface oxidation of FeCr alloys with 18, 28, and 43 mass‐% Cr was investigated in situ using grazing‐incidence X‐ray absorption spectroscopy (GIXAS) at the chromium and iron K‐edges. Oxidation in air was monitored in situ in the temperature range from 290 K to 680 K. The standard GIXAS data analysis is extended for the treatment of a single layer model in order to estimate the chromium concentrations of the oxide layer and of the near‐interface substrate as well as the oxide layer thickness. XANES analysis shows transitions from b.c.c. Fe to corundum type Fe₂O₃ and from b.c.c. Cr to corundum type Cr₂O₃. The initial oxide layers are 1.1‐1.4 nm thick and contain 60‐90 mass‐% chromium, while the near‐interface substrate is depleted in Cr. During heating, iron oxide growth dominates up to 560‐600 K. Then the chromium oxide layer loses its passivation effect and Cr oxidation sets in.     

Synthesis and characterization of organometallic conjugated polymers containing tricarbonyl(arene)chromium unit and platinum

Novel organometallic conjugated polymer containing (η⁶-arene)Cr(CO)₃ and platinum in the main chain was synthesized by dehydrohalogenation coupling reaction of (η⁶-1,4-diethynylbenzene)tricarbonylchromium with trans-(PBu₃)₂PtCl₂. The polymer was soluble in common organic solvents and has the number-average molecular weight of 31,000 by GPC analysis. The polymer exhibited an absorption peak derived from π-π^∗ interaction at 358 nm in the UV-Vis spectrum, which showed a red shift of approximately 90 nm compared to that of the model compound. The photochemical ligand exchange reaction of the polymer was also investigated.     

Oxygen chemisorption on divalent chromium ions in chromosilicate systems

A study has been made of the chemisorption of O₂ from various gaseous media on divalent chromium ions in chromosilicate systems under dynamic conditions. After passing through the chemisorbent layer the residual O₂ content of the gaseous mixtures is 10^–6–10^–7 vol. %. The adsorption capacity of the chemisorbents increases in proportion to their Cr(II) content and decreases as the moisture content increases in the gas mixture from which the oxygen is absorbed. The chemisorbents can be repeatedly regenerated by treating them with hydrogen.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2500–2505, November, 1992.     

聚合物材料中六价铬萃取方法研究

本研究作为起草国际电工委员会标准IEC 62321, Ed.1的第3次国际实验室间比对实验的一部分,考察了用碱溶液对聚合物样品中六价铬进行萃取时样品的基体材料、粒径和萃取时间对萃取效率的影响.研究选取了3种不同粒径 (<125 μm,125～250 μm和250～500 μm) 的ABS、PVC和EVA/PE样品.用50 mL 0.5 mol/L NaOH-0.28 mol/L Na2CO3混合碱性消解液在90～95 ℃下萃取样品中的六价铬,并在1～6 h内逐渐增加萃取时间.测试结果表明:聚合物中六价铬的萃取率明显地受到样品基体材料的影响,PVC材料有很好的萃取效果,ABS中的六价铬也能被有效萃取出;而EVA/PE材料中的六价铬则几乎不能被萃取.对PVC和ABS,3 h的萃取时间基本能达到最大萃取率,而样品粒径在减小至＜250 μm后,萃取率会明显提高.     

Neue Alkalimetallchromchalkogenide und ihre Struktursystematik

New Alkali Metal Chromium Chalcogenides and their Structural Classification The compounds RbCr₃S₅, K₃Cr₁₁S₁₈, RbCr₅Se₈ and CsCr₅Se₈ could be obtained in the form of wellshaped crystals via fusion reactions of the alkali metal carbonates with chromium and the corresponding chalcogen. The compounds crystallize in the monoclinic space groups C2/m (RbCr₃S₅: a = 19.372(3) Å, b = 3.498(1) Å, c = 12.119(2) Å, β = 122.78(1)°, Z = 4; K₃Cr₁₁S₁₈: a = 41.876(3) Å, b = 3.463(1) Å, c = 16.315(3) Å, β = 150.07(1)°, Z = 2; RbCr₅Se₈: a = 18.737(2) Å, b = 3.623(1) Å; c = 9.016(1) Å, β = 104.65(1)°, Z = 2; CsCr₅Se₈: a = 18.795(2) Å, b = 3.637(1) Å, c = 9.104(1) Å, β = 104.52(1)°, Z = 2). We propose a structure classification from group-subgroup-relations. MAPLE calculations reveal that the reactions of the binary chalcogenides to yield the ternary compounds are exothermic in each case and are dependent on the chromium/alkali metal ratio in the ternary chalcogenides.     

Penicillamin-Komplexe des Nickels,Chroms und Molybdäns — Strukturelle Besonderheiten und biologische/medizinische Relevanz

Penicillamine Complexes of Nickel, Chromium, and Molybdenum — Structural Particularity and Biological/Medical Relevance The compounds Tl₂[Ni^II(H₂O)₆][Ni^II(D-pen)(L-pen)]₂[Ni^II(SCN)₂(H₂O)₄] 1 , Tl[Ni^II(D-pen)₂H] · H₂O 2 , Tl[Cr^III(D-pen)₂] 3 , and Na₂[MoO₄(pen)₂] · 3 CH₃OH · 3 H₂O 4 have been prepared by the reaction of nickel nitrate (for 1 ), nickel acetate (for 2 ), potassium chromate (for 3 ), and sodium molybdate (for 4 ) with D- and D, L-penicillamine, respectively. They were characterized by single-crystal X-ray structure analysis and other physical methods. Whereas penicillamine acts as a bidentate (N, S)-ligand in 1 and 2 , Cr^III (in 3 ), and Mo^V (in 4 ) are coordinated to the three ligand atoms N, O, and S. The presence of three different types of Ni^II-complexes a cationic, a neutral, and an anionic one in 1 is remarkable. For crystal data see Inhaltsübersicht.     

碳掺杂六方氮化硼/二硫化钼吸附还原六价铬和助催化降解有机污染物

针对二硫化钼(MoS₂)因易团聚导致去除六价铬[Cr(Ⅵ)]容量低的问题, 利用六方氮化硼(BN)良好的吸附性和化学稳定性, 以多巴胺作为BN改性剂, 通过煅烧法和水热法制得碳掺杂六方氮化硼(c-BN)负载MoS₂纳米复合材料(c-BN@MoS₂). 研究了室温条件下c-BN@MoS₂对Cr(Ⅵ)的吸附还原和助催化降解有机污染物的性能. 实验结果表明, c-BN@MoS₂在40 min内对50 mg/L的Cr(Ⅵ)吸附还原去除率高达95%以上, 且以将 Cr(Ⅵ)还原至Cr(Ⅲ)为主, 在pH值为2、 温度为25 ℃条件下去除Cr(Ⅵ)最大容量可达401 mg/g, 显著高于 MoS₂(98 mg/g). 分析显示, c-BN不仅提高了MoS₂的平均孔径, 还可促进MoS₂生成金属特性的1T相, 有利于吸附Cr(Ⅵ)和加快氧化还原过程中的电子转移. 在Fe²⁺/PMS(过一硫酸氢盐)催化体系加入c-BN@MoS₂, 该体系对磺胺甲恶唑的降解性能明显增强, 其反应速率常数提高3倍, 这主要归因于c-BN@MoS₂明显加快了Fe³⁺到Fe²⁺的转变, 导致更多?OH产生, 达到增强降解污染物的目标.