Zinc complexes acetylacetone

Agrostis tenuis, 963 Zinc, alkylalkoxy-synthesis, 340 Zinc, alkylphenoxy-synthesis, 340 Zinc, dialkyl-oxidation, 342 Zinc complexes acetylacetone, 372 amidines... 

Other methods reported for the determination of beryllium include UV-visible spectrophotometry [80,81,83], gas chromatography (GC) [82], flame atomic absorption spectrometry (AAS) [84-88] and graphite furnace (GF) AAS [89-96]. The ligand acetylacetone (acac) reacts with beryllium to form a beryllium-acac complex, and has been extensively used as an extracting reagent of beryllium. Indeed, the solvent extraction of beryllium as the acety-lacetonate complex in the presence of EDTA has been used as a pretreatment method prior to atomic absorption spectrometry [85-87]. Less than 1 p,g of beryllium can be separated from milligram levels of iron, aluminium, chromium, zinc, copper, manganese, silver, selenium, and uranium by this method. See also Sect. 5.74.9. 

A broad range of metal centers have been used for the complexation of functional ligands, including beryllium [37], zinc, transition metals such as iridium [38], and the lanthanide metals introduced by Kido [39], especially europium and terbium. Common ligands are phenanthroline (phen), bathophenanthrolin (bath), 2-phenylpyridine (ppy), acetylacetonate (acac), dibenzoylmethanate (dbm), and 11 thenoyltrifluoroacetonate (TTFA). A frequently used complex is the volatile Eu(TTFA)3(phen), 66 [40]. 

SWV was used for the investigation of charge transfer kinetics of dissolved zinc(II) ions [215-218] and uranyl-acetylacetone [219], cadmium(II)-NTA [220] and mthenium(III)-EDTA complexes [221], and the mechanisms of electrode reactions of bismuth(III) [222], europium(III) [223,224] and indium(III) ions [225], 8-oxoguanine [226] and selenium(IV) ions [227,228]. It was also used for the speciation of zinc(II) [229,230], cadmium(II) and lead(II) ions in various matrices [231-235]. 

Conventional Ziegler catalysts are not suitable for use with acrylonitrile because, among other reasons, the monomer reacts with the catalyst or forms complexes with it. Recently, modified catalysts have been developed in Natta s laboratory (106), using such combinations as Chromium acetylacetone plus dibutyl zinc,... 

There are now numerous, metal-linked oligomeric (and polymeric) systems that fall into this category. For example, the acetylacetonates of manganese(II), nickel(II) and zinc(II) have long been known to be trimeric while the cobalt(II) complex is tetrameric, with three (3-diketonate oxygen atoms bridging adjacent metal centres in a linear array in each case. Other more recent examples include systems built... 

In solution, the monomer of anhydrous Co (AA) 2 apparently is tetrahedral (12), It is reasonable to expect that the monomeric j3-ketoenolate complexes of the alkali earth metals as well as manganese(II), iron(II), zinc(II), cadmium(II), and lead(II) also will be tetrahedral (18). However, in the solid state the manganese(II), iron(II) (19). and zinc(II) (6) complexes with acetylacetone apparently are polymerized (18). The cation B(AA)2" very likely also contains a tetrahedral BO4 unit. 

Saunders and Frisch (2) cite certain catalysts used to Induce an isocyanate-urethane (allophanate) reaction. They are zinc octoate, cobalt napthanate and cobalt octoate and are claimed to yield 95% allophanate. An experiment was designed observing the catalytic effect of these metal complexes under varied concentrations and over time. Ferric acetylacetonate, a catalyst known to Influence an isocyanate-carboxyl reaction, was included 1n the study. The catalysts were added individually and 1n combinations of two into a polyurethane-polyisocyanate system. Concentrations varied from 1.50% to 8.00% by weight. 

Complexes of higher coordination number are often in equilibrium with the tetrahedral form and may be isolated by increasing the ligand concentration or by adding large counter ions, e.g. [M(NH3)6] +, [M(en)3]2+ or [M(bipy)3]2+. With acetylacetone, zinc achieves both 5- and... 

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