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71.
Abed Al-Aziz Al-Quntar 《Journal of organometallic chemistry》2005,690(10):2504-2514
This article describes our recent methods for the synthesis of substituted vinylphosphonates by reacting 1-alkynylphosphnates with group (IV) complexes. cis-Vinylphosphonates, 1,3-butadienylphosphonates, 1-(hydroxymethyl)vinylphosphonates, 2-(hydroxymethyl)vinylphosphonates, (E) 3-oxo-1-alkenylphosphonates were produced as a result of the reactions between zirconium complexes and 1-alkynylphosphonates. On the other hand, titanium complexes afford 3-aminovinylphoshonates, 1,4-bis-phosphonates, and various other di- and tri-substituted vinylphosphonates. An evaluation of access of these recently synthesized vinylphosphonates as MMP-2 inhibitors has shown that certain compounds are very potent and promising. 相似文献
72.
稀土及杂质元素对ZA27合金晶间腐蚀的影响 总被引:10,自引:0,他引:10
为了从本质上了解杂质与稀土元素对锌铝合金晶间腐蚀的影响 ,探索抑制合金晶间腐蚀的有效途径 ,依据晶界的大角度重位点阵理论编制出相应计算机软件 ,建立含稀土、杂质及 η相颗粒的α相大角度晶界原子集团模型 ,采用递归法计算了α相晶界间的电荷转移 ,由此讨论了杂质 (Pb、Sn、Cd)及稀土元素 (La、Y)对Zn、Al电极电位的影响 .结果表明 ,杂质Pb、Sn、Cd增大原子间的电荷转移量 ,提高Zn、Al电极电位差 ,加速合金的腐蚀 ,稀土元素减小原子间的电荷转移量 ,降低Zn、Al电极电位差 ,具有抑制晶间腐蚀的作用 . 相似文献
73.
Ismail Boz Gulin Selda Pozan Mehmet Ali Gürkaynak 《Reaction Kinetics and Catalysis Letters》2004,83(1):137-146
Bimetallic Cu/Mg, Ca, Ba mixed oxide compounds acted as catalyst in the dehydrogenation of tetradecanol into tetradecanal,
and were characterized by thermal gravimetric analysis, surface area, X-ray diffraction, temperature-programmed reduction
and desorption of CO2. Alkaline earth oxides increased the total basic site concentration in the order of Mg>Ca>Ba. A correlation was found between
the total basic site concentration and initial dehydrogenation rate.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
74.
V Babizhetskyy 《Journal of solid state chemistry》2004,177(2):415-424
Solid state phase equilibria in the ternary Gd-Si-B phase diagram have been proposed at 1270 K using X-ray diffraction, scanning electron microscopy and electron probe microanalysis. Prior to this work, the binary systems Gd-B, Gd-Si and Si-B have also been reinvestigated. The main characteristic of the ternary diagram is the occurrence of two new ternary compounds Gd5Si2B8 and Gd5Si3B0.64. The former crystallizes in tetragonal symmetry, space group P4/mbm with unit cell parameters a=7.2665(3), c=8.2229(7) Å, the second one presents hexagonal symmetry, space group P63/mcm with unit cell parameters a=8.5080(4),c=6.4141(2) Å. The X-ray structures of the two structurally related phases Gd5Si3B0.64 and host binary Gd5Si3 have been refined from three-dimensional single-crystal intensity data to the final R values of 0.036 (Rw=0.046) and 0.046 (Rw=0.055) for 457 and 401 reflections, respectively with [F>4σ(F)]. Both structures exhibit the Mn5Si3-type structure, with in addition for Gd5Si3B0.64 a partial occupancy by boron of the normally vacant interstitial site at the center of the Gd6 octahedron, which corresponds to the origin of the unit cell. Bonding between the interstitial boron atoms and the gadolinium ones forming the Gd6B polyhedra is indicated by the decrease in the corresponding Gd-Gd distances and consequently in the unit cell volume. Finally, the Gd-Si-B phase diagram is compared with the previously reported Er-Si-B, at 1070 K. 相似文献
75.
迄今未见任何稀土氨基酸络合物的ESR波谱报道,本文在合成Gd3+分别与甘氨酸、β-丙氨酸、谷氨酸、天冬氨酸和天冬酰胺五种氨基酸络合物的基础上,测定了不同温度下,水溶液、粉末及分子筛吸附样品的ESR谱,讨论了络合物中晶体场强,对称性及成键特性。 相似文献
76.
The effects of the organometallic compounds Bu2Sn-D -(?;)sorbitol, Bu2Sn-D -(+)glucose, Bu2Sn-D -(?)fructose and Bu2Sn-D -(+)glyceraldehyde were tested in vivo on different stages of Ascidian development, larval movement and metamorphosis. Organotin(IV) complexes are organometallic compounds widely used as industrial biocides, antifouling agents and agricultural fungicides and are toxic to a range of organisms. Two-cell stage embryos, if incubated for one hour in the organotin (IV) solutions, stopped the cleavage, which was restored when they were transferred into normal sea water. The gastrula stage was seriously affected in 10?4mol dm?3 solutions of the above-mentioned complexes: 85% of the embryos were anomalous neurulae with open neural folds, 5% were twisted larvae. The gastrulae, when incubated for 1 h in 10?5mol dm?3 solutions, developed twisted larvae in ovular envelopes and immobile larvae with twisted tails. Larvae treated with 10?4mol dm?3 and 10?5 mol dm?3 Bu2Sn-D -(?)sorbitol, Bu2Sn-D -(+)glucose and Bu2Sn-D -(+)glyceraldehyde solutions stopped swimming, did not metamorphose and afterwards underwent cytolysis. An initial hyperactivity of circular movements, followed by immobility, was observed in the larvae incubated in Bu2Sn-D -(?;)fructose. 相似文献
77.
78.
Dithiocarbamate functions were incorporated into different polyacrylamide matrices crosslinked with a flexible and hydrophilic
crosslinking agent, tetraethyleneglycol diacrylate (TEGDA), and their complexation behaviours were investigated. Crosslinked
polyacrylamides with varying extents of the tetrafunctional TEGDA crosslinks were prepared by free radical solution polymerization
at 60°C using potassium persulphate as initiator in ethanol. The dithiocarbamate functionality was incorporated into these
polyacrylamides by a two-step polymer-analogous reaction involving (i)trans-amidation with ethylenediamine and (ii) dithiocarbamylation of the aminopolyacrylamide with carbon disulphide and alkali.
The complexations of dithiocarbamate with Cu(II), Ni(II), Zn(II), Co(II) and Hg(II) ions were followed under different conditions.
The metal ion intake varied with the extent of the crosslinking agent and the observed trend in complexation is Hg(II) > Cu(II)>
Zn(II)> Co(II)> Ni (II). The time-course of complexation, the possibility of recycling, swelling characteristics, and spectral
and thermal analyses were carried out. The thermal stability increases upon complexation with metal ions. 相似文献
79.
István Szilágyi László. Horváth Imre Labádi Klara Hernadi István Pálinkó Tamás Kiss 《Central European Journal of Chemistry》2006,4(1):118-134
An imidazolate-bridged copper(II)-zinc(II) complex (Cu(II)-diethylenetriamino-μ-imidazolato-Zn(II)-tris(2-aminoethyl)amine perchlorate (denoted as “Cu,Zn complex”) and a simple copper(II) complex (Cu(II)-tris(2-aminoethyl)
amine chloride (“Cu-tren”) were prepared and immobilised on silica gel (by hydrogen or covalent bonds) and montmorillonite
(by ion exchange). The immobilised substances were characterised by FT-IR spectroscopy and their thermal characteristics were
also studied. The obtained materials were tested in two probe reactions: catalytic oxidation of 3,5-di-tert-butyl catechol (DTBC) (catecholase activity) and the decomposition of hydrogen peroxide (catalase activity). It was found
that the catecholase activity of the Cu,Zn complex increased considerably upon immobilization on silica gel via hydrogen bonds and intercalation by ion exchange among the layers of montmorillonite. The imidazolate-bridged copper(II)-zinc(II)
complex and its immobilised versions were inactive in hydrogen peroxide decomposition. The Cu(II)-tris(2-aminoethyl)amine
chloride complex displayed good catalase activity; however, immobilisation could not improve it. 相似文献