Cobalt dioxygen carriers

R Volume 2,1993,292 pp. 109.50/ 70.00 ISBN 1-55938-272-4 CONTENTS Introduction, Robert W. Hay. Dynamics of Iron (II) and Cobalt (II) Dioxygen Carriers, P. Richard Warburton and Daryle H. Busch. Homodinuclear Metallobiosites, David... 

Cyclodene Complexes Relationships between Macrocyclic Ring Size, Lacunar Cavity Shape, and Dioxygen Affinity of the Cobalt-Cyclidene Dioxygen Carriers. 

REVERSIBLE COBALT(II) AND IRON(II) DIOXYGEN CARRIERS OF TOTALLY SYNTHETIC LACUNAR CYCLIDENE COMPLEXES ... 

Busch, D.H. Alcock, N.W. Iron and cobalt "lacunar" complexes as dioxygen carriers. Chem. Rev. 1994, 94. 585-623. 

Membrane processes involve cobalt(salen) or cyclidene type dioxygen carriers in a solution immobilized in the small pores of a thin, porous polymer layer. The reversible uptake and release of 0 in reactions of... 

Cobalt complexes with cyclic and acyclic polyamines as hgands in aqueous solutions as dioxygen carriers 12CCR316. 

Various cobalt (II) complexes, usually referred to as synthetic dioxygen carriers, are known to interact reversibly with dioxygen under ambient conditions, affording predominantly dioxygen complexes of different types. 

The general features of oxygenation equilibria and autoxidation involving cobalt-based lacunar cyclidene dioxygen carriers have been extensively studied by Busch and coworkers with special reference to dioxygen affinities and their correlation with structural features Lacunar systems have considerable activities for reversible dioxygen binding in their cavities under ambient conditions. 

The autoxidation of dioxygen carriers may involve both metal-centered oxidation to Co and ligand oxidation, leading to ligand destmction. Typical Mgand oxidations involve oxidative dehydrogenation of -CHyNH-to imine bonds as in the case of cobalt (II) complexes of Pydien and y-carbon to carbonyl group oxidations in macrocyclic p-diimine chelates ... 

It has long been known that, when bound to cobalt(II), the pyridine-based chelate ligands 2,2 -bipyridine (bipy), 1,10-phenanthroline (phen), and 2,2 6, 2"-terpyridine (terpy) form complexes that react with dioxygen in aqueous solution (32-34). The mixed-ligand complexes [Co(terpy)(bipy)]2+ and [Co(terpy)(phen)]2+ can act as oxygen carriers in aqueous solutions at pH values as low as 3.0 (34b), and the superoxo species thus formed are apparently dinuclear. In addition, the dinuclear bipyridine complex [(bipy)2Coin(/ 2-0 )(/ 2-02 )CoIn(bipy)2 ]3+ has been shown to catalyze the oxidation of 2,6-di-ter -butylphenol to the feri-butyl-substituted diphenoquinone and quinone (35). 

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