Ammonium tetrathiomolybdate as a novel electrode material for convenient tuning of the kinetics of electrochemical O2 reduction by using iron–porphyrin catalysts

2016 ◽  
Vol 4 (18) ◽  
pp. 6819-6823 ◽  
Author(s):  
Sudipta Chatterjee ◽  
Kushal Sengupta ◽  
Sabyasachi Bandyopadhyay ◽  
Abhishek Dey
Keyword(s):  
Electron Transfer ◽  
Electrode Material ◽  
Deposition Time ◽  
Active Species ◽  
Iron Porphyrin ◽  
Gold Electrodes ◽  
Redox Active ◽  
O2 Reduction ◽  
Ammonium Tetrathiomolybdate ◽  
Kinetics Of

Ammonium tetrathiomolybdate modified gold electrodes can easily tune the rate of electron transfer to the redox active species when the deposition time is varied.

scholarly journals How to Control the Rate of Heterogeneous Electron Transfer Across the Rim of M6L12 and M12L24 Nanospheres

2020 ◽  
Author(s):  
Riccardo Zaffaroni ◽  
Eduard.O. Bobylev ◽  
Plessius, Raoul ◽  
Jarl Ivar van der Vlugt ◽  
Joost reek
Keyword(s):  
Electron Transfer ◽  
Active Species ◽  
Transition Metal Catalysts ◽  
Supramolecular Assemblies ◽  
Fine Tuning ◽  
Transfer Rates ◽  
Heterogeneous Electron Transfer ◽  
Redox Active ◽  
Kinetics Of ◽  
Fine Tune

Catalysis in confined spaces, such as provided by supramolecular cages, is quickly gaining momentum. It allows for second coordination sphere strategies to control the selectivity and activity of transition metal catalysts, beyond the classical methods like fine-tuning the steric and electronic properties of the coordinating ligands. Only a few electrocatalytic reactions within cages have been reported, and there is no information regarding the electron transfer kinetics and thermodynamics of redox-active species encapsulated into supramolecular assemblies. This contribution revolves around the preparation of M<sub>6</sub>L<sub>12 </sub>and larger M<sub>12</sub>L<sub>24</sub> (M= Pd or Pt) nanospheres functionalized with different numbers of redox-active probes encapsulated within their cavity, either in a covalent fashion via different types of linkers (flexible, rigid and conjugated or rigid and non-conjugated) or by supramolecular hydrogen bonding interactions. The redox-probes can be addressed by electrochemical electron transfer across the rim of nanospheres and the thermodynamics and kinetics of this process are described. Our study identifies that the linker type and the number of redox probes within the cage are useful handles to fine-tune the electron transfer rates, paving the way for the encapsulation of electro-active catalysts and electrocatalytic applications of such supramolecular assemblies.

scholarly journals How to Control the Rate of Heterogeneous Electron Transfer Across the Rim of M6L12 and M12L24 Nanospheres

2020 ◽  
Author(s):  
Riccardo Zaffaroni ◽  
Eduard.O. Bobylev ◽  
Plessius, Raoul ◽  
Jarl Ivar van der Vlugt ◽  
Joost reek
Keyword(s):  
Electron Transfer ◽  
Active Species ◽  
Transition Metal Catalysts ◽  
Supramolecular Assemblies ◽  
Fine Tuning ◽  
Transfer Rates ◽  
Heterogeneous Electron Transfer ◽  
Redox Active ◽  
Kinetics Of ◽  
Fine Tune

Catalysis in confined spaces, such as provided by supramolecular cages, is quickly gaining momentum. It allows for second coordination sphere strategies to control the selectivity and activity of transition metal catalysts, beyond the classical methods like fine-tuning the steric and electronic properties of the coordinating ligands. Only a few electrocatalytic reactions within cages have been reported, and there is no information regarding the electron transfer kinetics and thermodynamics of redox-active species encapsulated into supramolecular assemblies. This contribution revolves around the preparation of M<sub>6</sub>L<sub>12 </sub>and larger M<sub>12</sub>L<sub>24</sub> (M= Pd or Pt) nanospheres functionalized with different numbers of redox-active probes encapsulated within their cavity, either in a covalent fashion via different types of linkers (flexible, rigid and conjugated or rigid and non-conjugated) or by supramolecular hydrogen bonding interactions. The redox-probes can be addressed by electrochemical electron transfer across the rim of nanospheres and the thermodynamics and kinetics of this process are described. Our study identifies that the linker type and the number of redox probes within the cage are useful handles to fine-tune the electron transfer rates, paving the way for the encapsulation of electro-active catalysts and electrocatalytic applications of such supramolecular assemblies.

scholarly journals Redox-Active Monolayers Self-Assembled on Gold Electrodes—Effect of Their Structures on Electrochemical Parameters and DNA Sensing Ability

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 607 ◽  
Author(s):  
Kamila Malecka ◽  
Shalini Menon ◽  
Gopal Palla ◽  
Krishnapillai Girish Kumar ◽  
Mathias Daniels ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Transition Metal ◽  
Redox Activity ◽  
Gold Electrodes ◽  
Complex Structures ◽  
Transfer Coefficients ◽  
Sensing Properties ◽  
Redox Active ◽  
Electrochemical Parameters ◽  
Self Assembled

The background: The monolayers self-assembled on the gold electrode incorporated transition metal complexes can act both as receptor (“host” molecules) immobilization sites, as well as transducer for interface recognitions of “guest” molecules present in the aqueous solutions. Their electrochemical parameters influencing the sensing properties strongly depend on the transition metal complex structures. The objectives: The electrochemical characterization of the symmetric terpyridine–M2+–terpyridine and asymmetric dipyrromethene–M2+–terpyridine complexes modified with ssDNA probe covalently attached to the gold electrodes and exploring their ssDNA sensing ability were the main aims of the research presented. The methods: Two transition metal cations have been selected: Cu2+ and Co2+ for creation of redox-active monolayers. The electron transfer coefficients indicating the reversibility and electron transfer rate constant measuring kinetic of redox reactions have been determined for all SAMs studied using: Cyclic Voltammetry, Osteryoung Square-Wave Voltammetry, and Differential Pulse Voltammetry. All redox-active platforms have been applied for immobilization of ssDNA probe. Next, their sensing properties towards complementary DNA target have been explored electrochemically. The results: All SAMs studied were stable displaying quasi-reversible redox activity. The linear relationships between cathodic and anodic current vs. san rate were obtained for both symmetric and asymmetric SAMs incorporating Co2+ and Cu2+, indicating that oxidized and reduced redox sites are adsorbed on the electrode surface. The ssDNA sensing ability were observed in the fM concentration range. The low responses towards non-complementary ssDNA sequences provided evidences for sensors good selectivity. The conclusions: All redox-active SAMs modified with a ssDNA probe were suitable for sensing of ssDNA target, with very good sensitivity in fM range and very good selectivity. The detection limits obtained for SAMs incorporating Cu2+, both symmetric and asymmetric, were better in comparison to SAMs incorporating Co2+. Thus, selection of the right transition metal cation has stronger influence on ssDNA sensing ability, than complex structures.

scholarly journals Electrical conductivity in two mixed-valence liquids

2015 ◽  
Vol 17 (21) ◽  
pp. 14107-14114 ◽  
Author(s):  
Wenzhi Yao ◽  
Steven P. Kelley ◽  
Robin D. Rogers ◽  
Thomas P. Vaid
Keyword(s):  
Electrical Conductivity ◽  
Electron Transfer ◽  
Exchange Rate ◽  
Rate Constants ◽  
Room Temperature ◽  
Mixed Valence ◽  
Electrical Current ◽  
Active Species ◽  
Redox Active

Two mixed-valence room-temperature liquids are reported: BuFc–[BuFc+][NTf2−] (BuFc = n-butylferrocene) and TEMPO–[TEMPO+][NTf2−]. Both are conductors of DC electrical current, and their conductivity is modeled based on the electron-transfer self-exchange rate constants of their constituent redox-active species.

scholarly journals Modeling Interfacial Electron Transfer in the Double Layer: The Interplay Between Electrode Coupling and Electrostatic Driving

2019 ◽  
Author(s):  
Aditya Limaye ◽  
Adam Willard
Keyword(s):  
Electron Transfer ◽  
Double Layer ◽  
Electrical Potential ◽  
Potential Drop ◽  
Active Species ◽  
Transfer Reactions ◽  
Electronic Coupling ◽  
Interfacial Electron Transfer ◽  
Redox Active ◽  
Solvent Polarization

This manuscript presents a theoretical model for simulating interfacial electron transfer reactions within the electrical double layer. This model resolves the population density of redox active species and simulated electron transfer at the level of Marcus theory, with a fluctuating solvent polarization coordinate. In this model, the kinetics and thermodynamics of electron transfer depend on the values of the electronic coupling of species (to the electrode) and the electrical potential drop, respectively.

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