Cobalt acetylacetonate structure

Cobalt, trichlorotris(l,2-ethylenediamine)-conformation, 1, 197 Cobalt, (triethylcnetetramine)-isomerism, 1, 200,201 Cobalt, trinitrato-structure, 1,67 Cobalt, tris(acetylacetone)-structure, 1, 62,65,67 Cobalt, tris(bipyridyl)-structure, 1,64... 

The polymerization of butadiene to 1.2 polymers with anionic Ziegler type catalysts has been studied by Natta and co-workers (46). They have shown that isotactic 1.2-polybutadiene can be produced by the use of catalysts which are made up of components which have basic oxygen and nitrogen structures such as triethylaluminum with cobalt acetylacetonate or with chromium acetylacetonate. Natta and co-workers have shown that either syndiotactic or isotactic structures are produced depending on the ratio of aluminum to chromium. Syndiotactic structures are obtained at low aluminum to chromium ratios while isotactic polybutadiene is obtained at high ratios. The basic catalyst component is characteristic of syndiotactic catalysts. Natta, Porri, Zanini and Fiore (47) have also produced 1.2 polybutadiene using... 

Another supporting evidence for complex formation as a prerequisite to synergism was obtained from the study of the catalysis of phenyl isocyanate-butanol reaction by soluble organic cobalt compounds in presence and absence of DABCO catalyst. The results obtained are presented in Figures 4 and 5. It is evident that the combination of DABCO catalyst with divalent cobalt compounds shows synergistic effects while the trivalent cobalt acetylacetonate shows relatively low activity. The explanation of these observations is the structure of these compounds. 

Cobalt, tris(acetylacetone)-structure, 62, 65, 67 Cobalt, tris(bipyridyl)-structurc, 64... 

FIGURE 4.2 TEM micrographs of pyrocarbon/silica samples obtained on the basis of silica gel by pyrolysis of acetylacetone—AC-3 (a) glucose—G1 (b) acenaphthene—AN2 (c) nickel acetylacetonate—CSfji (d) cobalt acetylacetonate—CS o (e) and on the basis of pyrogenic silica by pyrolysis of CHjClj, C/A-300 (Cc=20% w/w) (f). (Adapted with permission from Gun ko, V.M., Leboda, R., Skubiszewska-Zi ba, J., Turov, V.V., and Kowalczyk, R, Structure of silica gel Si-60 and pyrocarbon/silica gel adsorbents thermally and hydrothermally treated, Langmuir 17, 2001b, 3148. Copyright 2001 American Chemical Society.)... 

The anionic nickel acetylacetonate catalyst gives only the cis, cis, trans product. Intermediate catalysts have already been seen to give cis, cis, cis structures which do not terminate but produce cis polybutadiene. This will also be seen later with cobalt iodide. At high temperatures or with strongly cationic systems the cyclic dodecatrienes are isomerized to the most stable trans, trans, trans structure. 

Precisely the last condition explains the fact that mainly ICC have been obtained by the immediate interaction of ligands and zero-valent metals. Thus, a large series of metal p-diketonates was synthesized in the absence of a solvent [513,634-638], for example, iron bis- and tra-acetylacetonates [635]. It was shown that other ligands can serve as activators or promoters in these processes. In particular, the introduction of a,a or y,y -bipy into the reaction mixture gives the possibility of isolating copper acetylacetonates and adducts of similar complexes of cobalt and nickel [636], meanwhile the p-diketonates of the metals above are not formed under conditions similar to those reported in Ref. 635. Under dissolution of more active metallic barium in the mixture of another p-dikctone - dipivaloyl-methane (DPM) - with dyglime (DG) or tetraglime (TG) in absolute pentane, the mononuclear complex [Ba(DPM)2(TG)] and binuclear complex [Ba2(DPM)4 ( t-H20)(DG)] were isolated and structurally characterized [637]. 

Active catalysts for butadiene polymerization are obtained from aluminium alkyl halides and soluble Co and Co salts and complexes. The structure of the organic grouping attached to the cobalt is not important, but compounds most widely employed are acetylacetonates and carboxylic acid salts such as the octoate and naphthenate. The activity of the catalyst and structure of the polymer are affected by the groupings in the complex. Catalysts from aluminium trialkyls and cobalt salts other than halides are relatively unstable and give syndiotactic 1,2-polybutadiene. If halogens are present, e.g., from CoClj or CoBrj,... 

Tris (trifluoroacetylacetonato) cobalt(III) is formed from a bidentate ligand trifluoro-acetylacetone CF3C(OH) = CHCO-CII J. The structure of the complex drawn. The isomerism predicted and drawn the structures of isomers if isomerism is possible. 

There are three types of the structures of the metal )9-diketonates in the solid state (viz., insular, cellular, and skeleton). The type of structure of ) -diketonates used in the epoxy compositions affects the catalytic action of these admixtures, so it is possible to regulate the curing rate of the epoxy-anhydride compositions by choosing the necessary modifier [209]. The acetylacetonates of manganese [182-185], zinc [186-189], cobalt [ 190-192,206-208], aluminum [ 193,194], chromium and zirconium [ 184,195, 196], iron [197], and some other metals as well as the )5-diketonates of, for example, neodymium [198], uranium [203], vanadium [205], and the... 

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