Macrocyclic Thiophene-Appended Cyanido-Bridged CoIII/FeII Complexes: Precursors to Mixed-valent Poly-thiophene Hybrid Materials

2009 ◽  
Vol 62 (10) ◽  
pp. 1214 ◽  
Author(s):  
Sharizal Hasan ◽  
Nathan L. Kilah ◽  
Manuel Martinez ◽  
Paul V. Bernhardt
Keyword(s):  
Hybrid Materials ◽  
Transition Metal Ions ◽  
Spectroscopic Properties ◽  
Trinuclear Complex ◽  
Metal Charge ◽  
Trinuclear Complexes ◽  
Redox Active ◽  
Charge Transfer Transitions ◽  
Active Transition ◽  
Metal Charge Transfer

The new cyanido-bridged mixed valent FeII/CoIII macrocyclic complexes [L2CoIII(μ-NC)FeII(CN)5]– and trans-[L2CoIII(μ-NC)FeII(CN)4(μ-CN)CoIIIL2]2+ have been prepared and characterized spectroscopically. The trinuclear complex trans-[L2Co(μ-NC)Fe(CN)4(μ-CN)CoL2](ClO4)2·11H2O has been characterized crystallographically. The di- and trinuclear complexes exhibit metal-to-metal charge transfer transitions characteristic of Class II mixed valent chromophores and their redox and spectroscopic properties have been analyzed by Hush theory. The thiophene group attached to the macrocycle L2 in these complexes may serve as a precursor to conducting polythiophene-based hybrid materials incorporating redox active transition metal ions.

scholarly journals Interaction of iron ions with melanin

2019 ◽  
Author(s):  
Andrzej Czesław Żądło ◽  
Tadeusz Sarna
Keyword(s):  
Redox Reactions ◽  
Transition Metal Ions ◽  
Iron Binding ◽  
Iron Ions ◽  
Paramagnetic Resonance ◽  
Redox Active ◽  
Active Transition ◽  
Electron Paramagnetic ◽  
Aerobic And Anaerobic ◽  
Anaerobic System

One of the antioxidant roles of melanin is binding redox-active transition metal ions. The aim of this study was to examine the redox reactions accompanying iron binding by melanin. Two kinds of synthetic eumelanin were mixed with iron (II) and iron (III) in the presence and absence of citrate and ADP in the aerobic and anaerobic system. The iron binding was examined by electron paramagnetic resonance (EPR) spectroscopy and thiocyanate assay. Obtained results indicate that although melanin reduces iron (III) that is unbound to this polymer, binding of iron (II) is accompanied by its oxidation by melanin.

Spectroelectrochemical behaviour of the trinuclear [Ru3O(O2CCH3)6(isonicotinamide)3] cluster

1989 ◽  
Vol 67 (10) ◽  
pp. 1632-1635 ◽  
Author(s):  
Henrique E. Toma ◽  
Carlos J. Cunha
Keyword(s):  
Oxidation States ◽  
Metal Charge ◽  
Trinuclear Cluster ◽  
Oxygen Ion ◽  
Redox Couples ◽  
Metal Metal ◽  
Charge Transfer Transitions ◽  
Central Oxygen ◽  
Acetonitrile Solutions ◽  
Metal Charge Transfer

The [Ru3O(OOCCH3)6(isonicotinamide)3] cluster exhibits reversible electrochemical and spectroelectrochemical behaviour in acetonitrile solutions, associated with a series of successive μ-oxo RuIVRuIVRuIII/RuIVRu1IIRuIII/…/RuIIRuIIRuII redox couples with E0 = 2.16, 1.21, 0.19, −0.98, and −1.4 V versus SHE. The metal-isonicotinamide and metal–metal charge–transfer transitions shift to lower energies as the oxidation states of the ruthenium ions decrease. In alkaline aqueous solution, the μ-oxo RuIIIRuIIIRuII cluster can be reversibly reduced to the μ-oxo RuIIIRuIIRuII product (E0 = −0.85 V); however, below pH 4, the reduction proceeds according to two successive steps, yielding RIIIRIIRuII species with loss of the central oxygen ion. These species can be reoxidized in the reverse potential scan, regenerating the µ-oxo RuIIIRuIIIRuII complex. Keywords: ruthenium–acetate clusters, cluster spectroelectrochemistry, cluster electrochemistry, ruthenium–isonicotinamide complex, trinuclear cluster.

Low-density lipoprotein modification by normal, myeloperoxidase-deficient and NADPH oxidase-deficient granulocytes and the impact of redox active transition metal ions

Redox Report ◽  
2002 ◽  
Vol 7 (2) ◽  
pp. 111-119 ◽  
Author(s):  
Claudia E. Gerber ◽  
Gernot Bruchelt ◽  
Gerhard Ledinski ◽  
Joachim Greilberger ◽  
Dietrich Niethammer ◽  
...  
Keyword(s):  
Transition Metal ◽  
Nadph Oxidase ◽  
Metal Ions ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Transition Metal Ions ◽  
Low Density ◽  
Redox Active ◽  
Active Transition ◽  
The Impact
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