Dioxygen with transition metals

The reaction of dioxygen with transition metal complexes has stimulated the curiosity of scientists for decades. Seminal studies by Vaska in the 1960s revealed that dioxygen coordinates reversibly to the the Ir center in (Ph3P)2lr(CO)Cl, 14 (Eq. 15) [101-104], Following this report, numerous groups reported dioxygen adducts of other late transition metals [105],... 

Dioxygen oxidizes transition metal ions in the lower valence state generating the hydroxyperoxyl radicals or superoxide ions [155,156]. The thermodynamic characteristics of these reactions are presented in Table 10.6. It is seen that all cited reactions are endothermic, except for the reaction of the cuprous ion with 02. The reaction of the ferrous ion with dioxygen has a sufficiently low enthalpy (28 kJ mol 3). 

One of the most fundamental questions when dealing with the activation of dioxygen by transition metal complexes is whether the process is controlled kinetically by ligand substitution or by electron transfer. A model system that involved the binding of dioxygen to a macrocyclic hexamethylcyclam Co(II) complex to form the correspond-... 

The present volume is a non-thematic issue and includes seven contributions. The first chapter byAndreja Bakac presents a detailed account of the activation of dioxygen by transition metal complexes and the important role of atom transfer and free radical chemistry in aqueous solution. The second contribution comes from Jose Olabe, an expert in the field of pentacyanoferrate complexes, in which he describes the redox reactivity of coordinated ligands in such complexes. The third chapter deals with the activation of carbon dioxide and carbonato complexes as models for carbonic anhydrase, and comes from Anadi Dash and collaborators. This is followed by a contribution from Sasha Ryabov on the transition metal chemistry of glucose oxidase, horseradish peroxidase and related enzymes. In chapter five Alexandra Masarwa and Dan Meyerstein present a detailed report on the properties of transition metal complexes containing metal-carbon bonds in aqueous solution. Ivana Ivanovic and Katarina Andjelkovic describe the importance of hepta-coordination in complexes of 3d transition metals in the subsequent contribution. The final chapter by Sally Brooker and co-workers is devoted to the application of lanthanide complexes as luminescent biolabels, an exciting new area of development. 

In summary, the bond energies for atomic oxygen ( OO and dioxygen ( O2O with transition metals are much smaller than with either carbon or hydrogen (Tables 5 8), and hereby provide the means to stabilize active forms of oxygen [ O - MO 02 M(02) 02- MOOM]. Although the... 

REDOX PROPERTIES OF DIOXYGEN AND ITS REACTIONS WITH TRANSITION METAL COMPLEXES... 

Some Properties of Dioxygen and its Reaction with Transition Metal Ions... 

Catalysis of hydrocarbon oxidation with dioxygen by transition metals... 

Partial oxidation reactions are usually carried out over transition metal oxides capable of changing their valent state during their interaction with reacting molecules. Naturally, zeolites with their alumina-silicate composition did not prove themselves as good oxidation catalysts. They failed also to serve as efScient catalyst supporters, since transition metals being introduced into the zeolite matrix lose their ability to activate dioxygen [3,4],... 

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