The First A-Frame-Containing Organometallic Polymer: Taking Advantage of the Site Selectivity in PdPt-Mixed Metal Bimetallics

Abstract ClPd(μ-dppm)₂PtCl (1) reacts with (CNC₆H₄–2-OCH₂–)₂ to form a sparingly soluble and thermally stable orange polymeric material 4. 1 reacts with 1 or 2 equivalents of CNC₆H₄–2-OCH₃ to form the soluble A-frame d⁸–d⁸ model complexes 2 [ClPd(μ-dppm)₂(μ-CNR)PtCl], and 3 [ClPd(μ-dppm)₂(μ-CNR)Pt(CNR)](Cl) (R = C₆H₄–2-OCH₃), respectively. IR (ν(NC) bridging versus terminal) and NMR data reveal an A-frame structure where the terminal CNR ligands are bonded to Pt. 4 which is amorphous (XRD) appears stable up to 290 °C (TGA), but exhibits an exothermic process between 215 and 255 °C upon the first scan in DSC, but disappears upon the second. Two compounds, model 2 (λ_e = 674 nm; τ_e = 0.38 ± 0.01 μs; Φ_e = 0.0079 (±10%)) and polymer 4 (λ_e = 660 nm; τ_e = 0.18 ± 0.01 μs; Φ_e = 0.0056 (±10%)) are luminescent at 77 K in the solid state and in fluid solution (PrCN). Graphical abstract The First A-Frame-Containing Organometallic Polymer: Taking Advantage of the Site Selectivity in PdPt-Mixed Metal Bimetallics Sébastien Clément, Shawkat Mohammed Aly, Karl Gagnon, Alaa S. Abd-El-Aziz, Michael Knorr, Pierre D. Harvey ClPd(μ-dppm)₂Cl₂ reacts with (CN–C₆H₄–O–CH₂–)₂ to form the first A-frame-containing organometallic polymer, which is unambiguously characterized with the use of model compounds. This polymer does not experience any weight loss up to 290 °C based on TGA measurements, but DSC traces reveal an irreversible process at 215 °C (DSC). The novel material is also luminescent at 77 K. For example, λ_e = 660 nm; τ_e = 0.18 ± 0.01 μs; Φ_e = 0.0056 (±10%) in PrCN. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. This article is dedicated to Professor Astruc.     

Utilization of Steric Hindrance at the Metal Site in Separation of Copper(ll) Chelates

Abstract

The chromatographic behavior of copper(II) chelates differing in the arrangement of their alkyl chains is influenced by the steric hindrance at the copper(II) site. This hindrance prevents the solvent molecules from coordinating on the remaining coordination positions, and thus R_F values of chelates decrease with increasing compression at the copper(II) site.     

Room-Temperature Structure of Xylitol-Bound Glucose Isomerase by Serial Crystallography: Xylitol Binding in the M1 Site Induces Release of Metal Bound in the M2 Site

Glucose isomerase (GI) is an important enzyme that is widely used in industrial applications, such as in the production of high-fructose corn syrup or bioethanol. Studying inhibitor effects on GI is important to deciphering GI-specific molecular functions, as well as potential industrial applications. Analysis of the existing xylitol-bound GI structure revealed low metal occupancy at the M2 site; however, it remains unknown why this phenomenon occurs. This study reports the room-temperature structures of native and xylitol-bound GI from Streptomyces rubiginosus (SruGI) determined by serial millisecond crystallography. The M1 site of native SruGI exhibits distorted octahedral coordination; however, xylitol binding results in the M1 site exhibit geometrically stable octahedral coordination. This change results in the rearrangement of metal-binding residues for the M1 and M2 sites, the latter of which previously displayed distorted metal coordination, resulting in unstable coordination of Mg²⁺ at the M2 site and possibly explaining the inducement of low metal-binding affinity. These results enhance the understanding of the configuration of the xylitol-bound state of SruGI and provide insights into its future industrial application.     

The Active Site Structure of Transition Metal Ion‐Chelating Ordered Mesoporous Carbon Fuel Cell Catalysts

Transition metal ion‐chelating ordered mesoporous carbons (TM‐OMCs) were studied as polymer electrolyte membrane fuel cell cathode catalysts. The active site structure of the TM‐OMCs was studied by X‐ray absorption spectroscopy in combination with variations of a range of synthesis variables of the TM‐OMCs. The variations were found to have significant influence on the catalyst structure both in the mesoscale and on the atomic local structure allowing for detailed conclusions on the nature of the active sites. The main active site was found to be FeN_x chelates. An additional highly active site was found and proposed to be a FeN_x‐dioxygen site. It was further found that the catalytic activity could be increased threefold by acid washing and subsequent heat treatment of the as‐synthesized TM‐OMC materials.     

污染场地的现场采样方法与若干思考

污染场地调查过程中采样是十分重要的环节,关系到数据是否能够精确的反应出该场地的被污染情况。本文简述了污染场地调查的主要程序,并在此基础上详述了样品采集的方法、种类以及现场采样过程中可能存在的问题,为有效、规范污染场地调查提供参。     

Metal Particle Size Determination of Supported Metal Catalysts

The variety of supported metal catalysts utilized in the operations of the petroleum and chemical industries emphasizes the importance of metal-catalyzed reactions. As a result, many scientific investigators have attempted to characterize and follow closely the changes in the crystallite size and shape of supported metal particles in commercial and simulated environments. From these efforts a massive production of experimental facts has emerged.     

Metal Particle Size Determination of Supported Metal Catalysts

The variety of supported metal catalysts utilized in the operations of the petroleum and chemical industries emphasizes the importance of metal-catalyzed reactions. As a result, many scientific investigators have attempted to characterize and follow closely the changes in the crystallite size and shape of supported metal particles in commercial and simulated environments. From these efforts a massive production of experimental facts has emerged.     

Metal polymers

Summary Styrene-co-ethyl methacrylate colloids were obtained by codeposition at 77 K of the monomers with several metals such as Pd, Au, Ag, Cu, Zn, Cd, Ga, In, Ge, Sn, Sb and Bi. The colloids were polymerized with different amounts of initiator (BPO) at 65°C for 3.5 h and a wide range of viscosity average molecular weights (M_V, 10⁴–10⁵ g/mol) were obtained depending upon the metal used. The metal colloid concentration and stability are reported. The medium particle size of In comonomer colloids was 49 å. The thermal stability and metal composition are also described. The copolymers are stable even at 310°C; Pd-poly(styrene-co-ethyl methacrylate) being the most stable. The metal content ranging between 0.11 and 3.76% w/w for the highest MW fraction and between 0.08 and 0.96% w/w for the lowest MW fraction. Copolymers with different colors were obtained depending on the metal used.     

Metal polymers

Summary Styrene-co-butyl methacrylate colloids were obtained by codeposition at 77 K of the monomers with several metals such as Pd, Au, Ag, Cu, Zn, Cd, Ga, In, Ge, Sn, Sb and Bi. The colloids were copolymerized with different amounts of initiator (BPO) at 65°C for 3.0 h and a wide range of viscosity average molecular weights (Mv, 10⁴–10⁵ g/mol) were obtained depending upon the metal used. The metal colloid concentration and stability are reported. A medium particle size of 60-244 Å comonomer colloids was found. The thermal stability and metal composition are also described. The copolymers are stable even at 380°C, Ga- poly(styrene-co-butyl methacrylate) being the most stable with 418°C. The metal content is ranging between 0.10 and 2.26% w/w for the highest MW fraction and between 0.20 and 2.41% w/w for the lowest MW fraction. Copolymers with different colors were obtained depending on the metal used.     

金属与金属化合物超细粉体的微孔过滤

叙述了金属与金属化合物超细粉体与液体过滤中的若干问题,主要介绍了有关过滤精度、滤速等计算方法,最后简单介绍了可用于过滤和洗涤的两种高分子精密微孔过滤机。     

Selforganization of Alkali Metal on a Catalytic Metal Surface

Oxidized diamond-supported Ni catalysts gave the best performance among the oxidized diamond-supported various metal catalysts for the decomposition of methanol to synthesis gas. Ni (5 wt%)/oxidized diamond afforded 82.5% conversion of methanol to give a CO to H₂ ratio of 1.7 at 573 K.     

Multinuclear Metal Carbonyl Alkoxide and Aryloxide Derivatives as Models for Metal Carbonyls Adsorbed on Metal Oxide Supports

The synthesis and characterization of two tungsten carbonyl dimers containing bridging alkoxide or aryloxide ligands are described. The crystal and molecular structures of [PPN]₂[W₂(CO)₈(OCH₂CF₃)₂], 1, and [Et₄N]₃[W₂(CO)₆-(OPh)₃]-CH₃CN, 2 , are reported and compared with the structures of tetranuclear tungsten derivatives previously described. The dimer 1 crystalizes in the triclinic space group P 1 with unit cell parameters a = 13.460(11) Å, b = 12.318(5) Å, c = 13.842(10) Å, α = 82.73(5)°, β = 59.11(5)°, γ= 80.09(5)°, V = 1938(2) ų, and Z = 1. The complex 2 crystalizes in the monoclinic space group P2₁/n with unit cell parameters a = 11.954(2) Å, b = 19.359(4) Å, c = 26.462(5) Å, β = 102.50(16)°, V = 5979(2) ų, Z = 4. Molecular modeling software was utilized to construct a tetranuclear derivative from 1 similar to the structurally characterized [W(CO)₃OH]₄₋⁴ tetramer. The two tetramers were found to possess similar molecular parameters. This supports the contention that dimers of type 1 are the precursors of the tetramers. Comparisons of the tungsten alkoxides and aryloxides with the behavior of W(CO)₆ on γ-alumina are provided.     

金属氮化物／碳化物加氢催化剂研究进展

过渡金属氮化物与碳化物是一类间充性化合物,其结构特点决定其在催化反应上具有独特的催化效果。本文介绍了过渡金属氮化物与碳化物基本性质与作为加氢催化剂的制备进展,综述了其在催化加氢,脱氢,脱硫等方面的研究进展,并展示了重要的理论研究意义和潜在的应用前景。     

Treatment of Synthetic Crudes with Metal Chlorides and Metal Carbonyls

Abstract

The removal of problematic synthetic crude compounds with limited amounts of transition metal chlorides, carbonyls and hydrido carbonyls was investigated. A middle distillate fraction containing pure compounds of nitrogen and sulphur that are typical of this fraction was used. Chlorides of copper, iron, tin and zinc showed significant potential for removal of the nitrogen compounds and ethyl and phenyl mercuric chlorides reacted with these compounds at 200[ddot]C. These chlorides reacted with mercaptans and alkyl sulphides to varying degrees and with the exception of ethyl mercuric chloride had little effect on benzo and dibenzothiophene. However, the carbonyls of cobalt and manganese were quite promising for these thiophenes. Hydrido carbonyls of these metals were more favourable for the nitrogen compounds. There is evidence of competition for sites on the solid metal salts.     

Nonferrous Metal Industry

Two Nonferrous Metals Projects Started in Oct.in TianjinIt is known that the two nonferrous metals projects of Western Mining Group and Beijing Asian-Pacific Xuanhao Group,which are rated as the major industrial projects by Tianjing Government,have been started in October in Jinnan District of this city. PhaseⅠ of the nonferrous metal enlargement project invested CNY 2.5 billion by Western Mining Group adopts the international advanced technology and equipment,producing copper bars 110 thousand tons,copp...     

Nonferrous Metal Industry

Ten Nonferrous Metals Output of China in 2008It was reported by National Bureau of Statistics of China: ten nonferrous metals output of China in December 2008 was 2.063 9 million tons, decreasing 2.3% year on year; the total ten nonferrous metals output of China in 2008 was 25.202 8 million tons, increasing 8.2% year on year.