Redox-active complexes

Keywords n-d interaction, 3d transition metal, Electronic conductivity, Magnetism, Redox-active complexes, TTF... 

Figure 9.2. Mechanisms of aminoglycoside toxicity. This schematic representation summarizes the principles of aminoglycoside toxicity discussed in the text. Treatment with the drugs leads to the formation of reactive oxygen species through a redox-active complex with iron and unsaturated fatty acid or by triggering superoxide production by way of NADPH oxidase. An excess of reactive oxygen species, not balanced by intracellular antioxidant systems, will cause an oxidative imbalance potentially severe enough to initiate cell death pathways. Augmenting cellular defenses by antioxidant therapy can reverse the imbalance and restore homeostasis to protect the cell.

Reactions of Redox-Activated Complexes with Gaseous Substrates... 

Parkes and co-workers have also conducted H NMR studies on s5movial fluid from patients with rheumatoid arthritis. Tbe nature of the nontransferrin-bound iron in the synovial fluid of patients with inflammatory joint disease was investigated. Transferrin is an iron ion transport protein. In these patients the synovial fluid contains non-transferrin-bound iron which appears to be in low-molecular-mass, redox-active complexes of unknown type. This form of iron has the adverse effect of stimulating free-radical lipid peroxidations involving oxygen. 500 MHz spin-echo H NMR spectroscopy was used to show that the incubation of patient synovial fluid with the powerful Fe(III)... 

The redox polymers, both of organic and inorganic origin (such as polyvinylpyridine modified by redox-active complexes of metals Prussian blue and related materials), can be considered as a version of electrodes of the second kind however, the equilibrium is usually estabhshed with respect to cations. Electron conducting polymers (polyanyline, polypyrrol, and so forth) also pertain, in the first approximation, to the electrodes of the second kind, which maintain equilibrium with respect to anion. Ion exchange polymer films on electrode surfaces form a subgroup of membrane electrodes. 

The direct electrochemical measurement of interactions of a Fc-peptide host (FcL) with metal ions M forming the redox active complex FcL-M, can be represented by Scheme 5.16. 

After a presentation of various methods of direct electrochemicai systhesis (D.G. Tuck) the redox properties of those types of complexes and their relationships with structure and reactivity have been discussed. In particular, the parameterisation of metal centred redox couples has been evaluated (A.B.P. Lever), synthetic, structural and electronic consequences of electron-transfer reactions have been presented (M. Gross and K. Wieghardt) and redox-active complexes discussed (J.A. McCleverty) as components of secondary harmonic generators in non-linear optical materials. 

Doxorubicin and other anthracyclines, such as daunorubicin, are believed to exhibit their antineoplastic activity through inhibition of topoisomerase II activity. This appears to occur in the absence of significant metal binding by the anthracyclines. Doxorubicin can, however, bind with iron(III) and this results in the formation of a redox-active complex that may cause untoward effects (Myers et al. 1986). Doxorubicin-iron(III) complexes have been shown to oxidatively damage membranes and inactivate protein kinase C, but the biological signficance of this is not well understood (Hannun et al. 1989). 

Cheng Z, Ren B, Zhao D, Liu X, Tong Z (2009) Novel thermotropic liquid crystalline and redox-active complexes of ionically self-assembled poly(ferrocenylsilane) and dendritic amphiphiles. Macromolecules 42 2762-2766... 

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