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Cobalt complex catalytic properties

Electrogenerated nickel(I)251 and cobalt(I)252 complexes of Salen (Salen = bis(salicylidene)ethane-1,2-diamine) have displayed good catalytic properties in the cleavage of carbon-halogen bonds in a variety of organic compounds. Recent research in this field has been reviewed.253... [Pg.487]

These sites must be considered to have different catalytic properties. The sites on top (Co atoms of low coordination) would be similar to that of the central atom of cobalt carbonyl complexes, and reactions on these should be similar to those in hydroformylation. Specifically, insertion reactions between n- and cr-ligands (CO... [Pg.171]

The application of perfluorous polyethers in biphasic catalysis was first described by Vogt (133), who also synthesized ligands based on hexafluor-opropene oxide oligomers to create metal complexes that are soluble in the perfluorous polyethers. The solvophobic properties of the fluorous solvent were successfully incorporated in the metal complexes catalytic oligomerization and polymerization reactions with nickel and cobalt complexes were demonstrated. [Pg.497]

Reactions and catalytic properties 20 of rhodium complexes in solution (160) Reactions catalysed by pentacyano- 36 cobaltate(H) (114)... [Pg.476]

Furthermore, it is proposed that the active structures of Co " and Co " in anhydrous acetic acid are represented largely by uncharged sixfold-coordinated complexes such as Co (OAc)2(HOAc)4 and Co" (OAc)3(HOAc)3. An addition of water, substituted benzaldehydes, benzoic acids, or phenols might result in exchange reactions with acetic acid ligands, and influence the catalytic properties analogously to the effects observed upon addition of zirconium(IV) acetate [14w]. Thus, only at high cobalt(II) concentrations catalytically less active dimers will play a relevant role. [Pg.451]

PEI can be applied as a polymer matrix because the PEI molecules contain amino groups which are capable of bonding with group VIII metal salts. Catalytic properties of coordination compounds of PEI have been thoroughly studied [57-62] The structure or active sites of PEI complexes with nickel, cobalt, rhodium and palladium ions is presented as a five-membered chelate ring ... [Pg.74]

Additives of the stearates of iron (IS), copper (CpS), cobalt (CbS), zinc (ZS), and lead (LS) within a certain concentration range were found to increase the polymerization rate of styrene and methylmethacrylate (MMA) in comparison with thermal polymerization. By initiating activity, they can be arranged as LS < CbS < ZS < IS < CpS. The decreases in the effective activation energy, the activation energy of the initiating reaction, and the kinetic reaction order with respect to monomer point to the monomer s active participation in chain initiation. IR spectroscopy data show that an intermediate monomer-stearate complex is formed and then decomposed into active radicals to initiate polymerization. The benzoyl peroxide (BP)-IS (or CpS) systems can be nsed for effective polymerization initiation. Concentration inversion of the catalytic properties of... [Pg.210]

In most cases, the nature of the spacer is the governing factor as far as optical properties are concerned. Pacman porphyrins, with rigid spacers such as anthracene and biphenylene, have received much attention due to the electro-catalytic properties of their cobalt complexes. Variations of both the dihedral angle and the distance between the porphyrm rings in these architectures have afforded examples of cofacial porphyrins linked by xanthene and dibenzofurane derivatives. Recent examples are detailed hereafter. [Pg.685]

Cobalt, nickel, iron, ruthenium, and rhodium carbonyls as well as palladium complexes are catalysts for hydrocarboxylation reactions and therefore reactions of olefins and acetylenes with CO and water, and also other carbonylation reactions. Analogously to hydroformylation reactions, better catalytic properties are shown by metal hydrido carbonyls having strong acidic properties. As in hydroformylation reactions, phosphine-carbonyl complexes of these metals are particularly active. Solvents for such reactions are alcohols, ketones, esters, pyridine, and acidic aqueous solutions. Stoichiometric carbonylation reaction by means of [Ni(CO)4] proceeds at atmospheric pressure at 308-353 K. In the presence of catalytic amounts of nickel carbonyl, this reaction is carried out at 390-490 K and 3 MPa. In the case of carbonylation which utilizes catalytic amounts of cobalt carbonyl, higher temperatures (up to 530 K) and higher pressures (3-90 MPa) are applied. Alkoxylcarbonylation reactions generally proceed under more drastic conditions than corresponding hydrocarboxylation reactions. [Pg.698]

Shibata s research field was further extended to the study of the catalytic property of cobalt complexes. In 1918 he and his elder brother, Keita Shibata (1877-1949), professor of phytochemistry and plant physiology at Tokyo Imperial University, found that myricetin, a kind of fiavonol, is easily oxidized in solution by cobalt complexes at room temperature, and they published the results in 1920 31). [Pg.140]

Busch and coworkers have synthesized a series of remarkable vaulted and lacunar cobalt(II) cyclidene complexes, which reversibly bind dioxygen and undergo autoxidation to cobalt(III) species. In some cases they exhibit catalytic properties in the oxidation of phenol derivatives. [Pg.313]


See other pages where Cobalt complex catalytic properties is mentioned: [Pg.739]    [Pg.117]    [Pg.27]    [Pg.233]    [Pg.114]    [Pg.70]    [Pg.131]    [Pg.238]    [Pg.240]    [Pg.138]    [Pg.536]    [Pg.169]    [Pg.177]    [Pg.471]    [Pg.364]    [Pg.479]    [Pg.177]    [Pg.63]    [Pg.324]    [Pg.138]    [Pg.536]    [Pg.158]    [Pg.927]    [Pg.478]    [Pg.76]    [Pg.91]    [Pg.234]    [Pg.47]    [Pg.250]    [Pg.64]    [Pg.266]    [Pg.284]    [Pg.249]    [Pg.3790]    [Pg.4015]    [Pg.6]   
See also in sourсe #XX -- [ Pg.140 ]




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