Osmium Bipyridine-Containing Redox Polymers Based on Cellulose and Their Reversible Redox Activity

2011 ◽  
Vol 116 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Hongliang Kang ◽  
Ruigang Liu ◽  
Huafeng Sun ◽  
Jieming Zhen ◽  
Qinmei Li ◽  
...  
Keyword(s):  
Redox Activity ◽  
Redox Polymers ◽  
Reversible Redox

scholarly journals Electron Inventory of the Iron-Sulfur Scaffold Complex HypCD Essential in [NiFe]-Hydrogenase Cofactor Assembly

2021 ◽  
Author(s):  
Sven T. Stripp ◽  
Jonathan Oltmanns ◽  
Christina S. Müller ◽  
David Ehrenberg ◽  
Ramona Schlesinger ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Redox Activity ◽  
Construction Site ◽  
Iron Ion ◽  
Paramagnetic Resonance ◽  
Iron Sulfur ◽  
Reducing Conditions ◽  
Reversible Redox ◽  
Electron Paramagnetic ◽  
Redox Conversion

The [4Fe-4S] cluster containing scaffold complex HypCD is the central construction site for the assembly of the [Fe](CN)2CO cofactor precursor of [NiFe]-hydrogenase. While the importance of the HypCD complex is well established, not much is known about the mechanism by which the CN– and CO ligands are transferred and attached to the iron ion. We developed an efficient protocol for the production and isolation of the functional HypCD complex that facilitated detailed spectroscopic investigations. The results obtained by UV/Vis-, electron paramagnetic Resonance (EPR)-, Resonance Raman-, Fourier-transform infrared (FTIR), and Mössbauer spectroscopy provide comprehensive evidence for an electron inventory fit to drive multi-electron redox reactions. We demonstrate the redox activity of the HypCD complex reporting the interconversion of the [4Fe-4S]2+/+ couple. Additionally, we observed a reversible redox conversion between the [4Fe-4S]2+ and a [3Fe-4S]+ cluster. MicroScale thermophoresis indicated preferable binding between the HypCD complex and its interaction partner HypEF under reducing conditions. Together, these results suggest a redox cascade involving the [4Fe-4S] cluster and a conserved disulfide bond of HypD that may facilitate the synthesis of the [Fe](CN)2CO cofactor precursor on the HypCD scaffold complex.

A TTFV–pyrene-based copolymer: synthesis, redox properties, and aggregation behaviour

RSC Advances ◽  
2015 ◽  
Vol 5 (30) ◽  
pp. 23952-23956 ◽  
Author(s):  
Eyad A. Younes ◽  
Kerry-Lynn M. Williams ◽  
Joshua C. Walsh ◽  
Celine M. Schneider ◽  
Graham J. Bodwell ◽  
...  
Keyword(s):  
Ph Value ◽  
Redox Properties ◽  
The Self ◽  
Redox Activity ◽  
Repeat Units ◽  
Aggregation Behaviour ◽  
Reversible Redox ◽  
Conjugated Copolymer ◽  
External Stimuli ◽  
Self Aggregation

A new π-conjugated copolymer containing tetrathiafulvalene vinylogue and pyrene repeat units was synthesized and exhibited reversible redox activity, while the self-aggregation behaviour in the solution phase was responsive to external stimuli such as solvent and pH value.

scholarly journals Ferrocene Introduced into 5-Methylresorcinol-Based Organic Aerogels

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1582 ◽  
Author(s):  
Ludmila V. Erkhova ◽  
Igor A. Presniakov ◽  
Michail I. Afanasov ◽  
Dmitry A. Lemenovskiy ◽  
Haojie Yu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Exchange Process ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Redox Activity ◽  
High Porosity ◽  
Reversible Redox ◽  
Amorphous Substrates ◽  
Structural Blocks ◽  
Organic Aerogels

The polycondensation sol–gel reaction of 5-methylresocinol and formaldehyde with additional compounds in reaction media is a relatively simple way to produce modified aerogels. In order to obtain aerogels with a large surface area and high porosity, the conditions for gel formation, the solvent exchange process before drying, and the supercritical drying process were optimized. A successful attempt was made to introduce ferrocene units into 5-methylresocinol-formaldehyde-based aerogels. The resulting aerogels are amorphous substrates, and no aggregated ferrocene units were found in their structures. All of the aerogel samples that were obtained are structurally similar despite differences in the original ferrocene units and their initial concentration. It was found that the inclusion limit of ferrocene structural blocks into an aerogel is ~6% wt. The structures of the inclusions in which all of the Fe atoms in the aerogel substrates were present in ferrocene/ferrocenium at an approximate ratio of 60/40 to 55/45 were confirmed by X-ray photoelectron spectroscopy and Mössbauer spectroscopy. Aerogels with ferrocene/ferrocenium inclusions are likely to exhibit reversible redox activity in reactions with gaseous reagents.

Reversible Redox Activity in Multicomponent Metal–Organic Frameworks Constructed from Trinuclear Copper Pyrazolate Building Blocks

2017 ◽  
Vol 139 (23) ◽  
pp. 7998-8007 ◽  
Author(s):  
Binbin Tu ◽  
Qingqing Pang ◽  
Huoshu Xu ◽  
Xiaomin Li ◽  
Yulin Wang ◽  
...  
Keyword(s):  
Metal Organic Frameworks ◽  
Building Blocks ◽  
Redox Activity ◽  
Reversible Redox ◽  
Metal Organic

scholarly journals Electron Inventory of the Iron-Sulfur Scaffold Complex HypCD Essential in [NiFe]-Hydrogenase Cofactor Assembly

2021 ◽  
Author(s):  
Sven T. Stripp ◽  
Jonathan Oltmanns ◽  
Christina S. Müller ◽  
David Ehrenberg ◽  
Ramona Schlesinger ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Redox Activity ◽  
Construction Site ◽  
Iron Ion ◽  
Paramagnetic Resonance ◽  
Iron Sulfur ◽  
Reducing Conditions ◽  
Reversible Redox ◽  
Electron Paramagnetic ◽  
Redox Conversion

The [4Fe-4S] cluster containing scaffold complex HypCD is the central construction site for the assembly of the [Fe](CN)2CO cofactor precursor of [NiFe]-hydrogenase. While the importance of the HypCD complex is well established, not much is known about the mechanism by which the CN– and CO ligands are transferred and attached to the iron ion. We developed an efficient protocol for the production and isolation of the functional HypCD complex that facilitated detailed spectroscopic investigations. The results obtained by UV/Vis-, electron paramagnetic Resonance (EPR)-, Resonance Raman-, Fourier-transform infrared (FTIR), and Mössbauer spectroscopy provide comprehensive evidence for an electron inventory fit to drive multi-electron redox reactions. We demonstrate the redox activity of the HypCD complex reporting the interconversion of the [4Fe-4S]2+/+ couple. Additionally, we observed a reversible redox conversion between the [4Fe-4S]2+ and a [3Fe-4S]+ cluster. MicroScale thermophoresis indicated preferable binding between the HypCD complex and its interaction partner HypEF under reducing conditions. Together, these results suggest a redox cascade involving the [4Fe-4S] cluster and a conserved disulfide bond of HypD that may facilitate the synthesis of the [Fe](CN)2CO cofactor precursor on the HypCD scaffold complex.

Structure and reaction mechanism of binary Ni–Al oxides as materials for lithium-ion battery anodes

2021 ◽  
Author(s):  
Noriyuki Sonoyama ◽  
Kaori Niki ◽  
Akihiro Koide ◽  
Mina Eguchi ◽  
Yoshitaka Ogasawara ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Negative Electrode ◽  
Lithium Ion ◽  
Diffusion Path ◽  
Redox Activity ◽  
Ion Diffusion ◽  
Reversible Redox ◽  
Double Hydroxide ◽  
Electrode Characteristics ◽  
Lithium Ion Diffusion

Using layered double hydroxide as a precursor, the negative electrode characteristics of Al3+ ion dissolved NiO were investigated. Al3+ ion shows reversible redox activity to Al when introduced into a host having electron conductivity and a lithium ion diffusion path.

Reversible redox activity of ferrocene functionalized hydroxypropyl cellulose and its application to detect H 2 O 2

2016 ◽  
Vol 140 ◽  
pp. 35-42 ◽  
Author(s):  
Pingping Li ◽  
Hongliang Kang ◽  
Chao Zhang ◽  
Weiwei Li ◽  
Yong Huang ◽  
...  
Keyword(s):  
Hydroxypropyl Cellulose ◽  
Redox Activity ◽  
Reversible Redox

scholarly journals Bioactivity Profiles of Cytoprotective Short-Chain Quinones

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1382
Author(s):  
Zikai Feng ◽  
Monila Nadikudi ◽  
Krystel L. Woolley ◽  
Ayman L. Hemasa ◽  
Sueanne Chear ◽  
...  
Keyword(s):  
Molecular Level ◽  
Short Chain ◽  
Redox Activity ◽  
Selection Strategy ◽  
Cytoprotective Activity ◽  
Reversible Redox ◽  
Human Hepatocarcinoma Cell Line ◽  
Mitochondrial Complex I Inhibitor ◽  
Bioactivity Profile ◽  
Hepatocarcinoma Cell Line

Short-chain quinones (SCQs) have been investigated as potential therapeutic candidates against mitochondrial dysfunction, which was largely thought to be associated with the reversible redox characteristics of their active quinone core. We recently reported a library of SCQs, some of which showed potent cytoprotective activity against the mitochondrial complex I inhibitor rotenone in the human hepatocarcinoma cell line HepG2. To better characterize the cytoprotection of SCQs at a molecular level, a bioactivity profile for 103 SCQs with different compound chemistries was generated that included metabolism related markers, redox activity, expression of cytoprotective proteins and oxidative damage. Of all the tested endpoints, a positive correlation with cytoprotection by SCQs in the presence of rotenone was only observed for the NAD(P)H:quinone oxidoreductase 1 (NQO1)-dependent reduction of SCQs, which also correlated with an acute rescue of ATP levels. The results of this study suggest an unexpected mode of action for SCQs that appears to involve a modification of NQO1-dependent signaling rather than a protective effect by the reduced quinone itself. This finding presents a new selection strategy to identify and develop the most promising compounds towards their clinical use.

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