A delocalized cobaltoviologen with seven reversibly accessible redox states and highly tunable electrochromic behaviour

2020 ◽  
Vol 56 (89) ◽  
pp. 13864-13867
Author(s):  
Iram F. Mansoor ◽  
Derek I. Wozniak ◽  
Yilei Wu ◽  
Mark C. Lipke
Keyword(s):  
Redox Potential ◽  
Electronic Coupling ◽  
Redox Active Ligands ◽  
Electrochromic Properties ◽  
Redox States ◽  
Redox Active

Cobalt was found to mediate strong electronic coupling between two viologen-like redox-active ligands, providing electrochromic properties that are easily tuned by the applied redox potential.

scholarly journals A Delocalized Cobaltoviologen with Seven Reversibly Accessible Redox States and Highly Tunable Electrochromic Behaviour

2020 ◽  
Author(s):  
Iram F. Mansoor ◽  
Derek Wozniak ◽  
yilei wu ◽  
Mark C. Lipke
Keyword(s):  
Electronic Properties ◽  
Class Ii ◽  
Electronic Coupling ◽  
Electrochromic Properties ◽  
Redox States ◽  
Redox Active ◽  
Electronic Delocalization ◽  
Terpyridine Ligands

Cobalt(II) mediates electronic coupling between two N-methyl-pyridinium-terpyridine ligands that are related to redox-active N,N-dialkyl-4,4'-bipyridinium dications (viologens). Borderline Class II/III electronic delocalization imparts the cobaltoviologen complex with distinct electronic properties (e.g. 7 accessible redox states) relative to those of viologens, leading to enhanced electrochromic properties.

scholarly journals A Delocalized Cobaltoviologen with Seven Reversibly Accessible Redox States and Highly Tunable Electrochromic Behaviour

2020 ◽  
Author(s):  
Iram F. Mansoor ◽  
Derek Wozniak ◽  
yilei wu ◽  
Mark C. Lipke
Keyword(s):  
Electronic Properties ◽  
Class Ii ◽  
Electronic Coupling ◽  
Electrochromic Properties ◽  
Redox States ◽  
Redox Active ◽  
Electronic Delocalization ◽  
Terpyridine Ligands

Cobalt(II) mediates electronic coupling between two N-methyl-pyridinium-terpyridine ligands that are related to redox-active N,N-dialkyl-4,4'-bipyridinium dications (viologens). Borderline Class II/III electronic delocalization imparts the cobaltoviologen complex with distinct electronic properties (e.g. 7 accessible redox states) relative to those of viologens, leading to enhanced electrochromic properties.

scholarly journals Exploring Coupled Redox and pH Processes with a Force Field-Based Approach: Applications to Five Different Systems

2020 ◽  
Author(s):  
Vinicius Cruzeiro ◽  
Gustavo Troiano Feliciano ◽  
Adrian Roitberg
Keyword(s):  
Force Field ◽  
Redox Potential ◽  
Desulfovibrio Vulgaris ◽  
Cytochrome C3 ◽  
Computational Tools ◽  
Redox States ◽  
Computational Performance ◽  
Redox Active ◽  
Constant Ph ◽  
Experimental Findings

Coupled redox and pH-driven processes are at the core of many important biological mechanisms. As the distribution of protonation and redox states in a system is associated with the pH and redox potential of the solution, having efficient computational tools that can simulate under these conditions become very important. Such tools have the potential to provide information that complement and drive experiments. In previous publications we have presented the implementation of the constant pH and redox potential molecular dynamics (C(pH,E)MD) method in AMBER and we have shown how multidimensional replica exchange can be used to significantly enhance the convergence efficiency of our simulations. In the current work, after an improvement in our C(pH,E)MD approach that allows a given residue to be simultaneously pH- and redox-active, we have employed our methodologies to study five different systems of interest in the literature. We present results for: capped tyrosine dipeptide, two maquette systems containing one pH- and redox-active tyrosine (α3Y and peptide A), and two proteins that contain multiple heme groups (diheme cytochrome c from Rhodobacter sphaeroides and Desulfovibrio vulgaris Hildenborough cytochrome c3). We show that our results can provide new insights into previous theoretical and experimental findings by using a fully force field-based and GPUaccelerated approach, which allows the simulations to be executed with high computational performance.

scholarly journals Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways

2020 ◽  
Vol 22 (44) ◽  
pp. 25467-25473 ◽  
Author(s):  
Keisuke Saito ◽  
Manoj Mandal ◽  
Hiroshi Ishikita
Keyword(s):  
Electron Transfer ◽  
Proton Transfer ◽  
Redox Potential ◽  
Driving Force ◽  
Electronic Coupling ◽  
Redox Potentials ◽  
Redox Active ◽  
Electron Transfer Pathways

Local proton transfer along redox-active low-barrier H-bonds can alter the driving force or electronic coupling for electron transfer, as the redox potential values depend on the H+ position in low-barrier H-bonds.

scholarly journals Exploring Coupled Redox and pH Processes with a Force Field-Based Approach: Applications to Five Different Systems

2020 ◽  
Author(s):  
Vinicius Cruzeiro ◽  
Gustavo Troiano Feliciano ◽  
Adrian Roitberg
Keyword(s):  
Force Field ◽  
Redox Potential ◽  
Desulfovibrio Vulgaris ◽  
Cytochrome C3 ◽  
Computational Tools ◽  
Redox States ◽  
Computational Performance ◽  
Redox Active ◽  
Constant Ph ◽  
Experimental Findings

Coupled redox and pH-driven processes are at the core of many important biological mechanisms. As the distribution of protonation and redox states in a system is associated with the pH and redox potential of the solution, having efficient computational tools that can simulate under these conditions become very important. Such tools have the potential to provide information that complement and drive experiments. In previous publications we have presented the implementation of the constant pH and redox potential molecular dynamics (C(pH,E)MD) method in AMBER and we have shown how multidimensional replica exchange can be used to significantly enhance the convergence efficiency of our simulations. In the current work, after an improvement in our C(pH,E)MD approach that allows a given residue to be simultaneously pH- and redox-active, we have employed our methodologies to study five different systems of interest in the literature. We present results for: capped tyrosine dipeptide, two maquette systems containing one pH- and redox-active tyrosine (α3Y and peptide A), and two proteins that contain multiple heme groups (diheme cytochrome c from Rhodobacter sphaeroides and Desulfovibrio vulgaris Hildenborough cytochrome c3). We show that our results can provide new insights into previous theoretical and experimental findings by using a fully force field-based and GPUaccelerated approach, which allows the simulations to be executed with high computational performance.

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

scholarly journals Small Molecule-Induced Intramolecular Electron “Pitch and Catch” in a RhodiumIComplex with Substitutionally Inert Redox-Active Ligands.

1999 ◽  
Vol 38 (18) ◽  
pp. 4176-4176
Author(s):  
Igor V. Kourkine ◽  
Caroline S. Slone ◽  
Chad A. Mirkin ◽  
Louise M. Liable-Sands ◽  
Arnold L. Rheingold
Keyword(s):  
Small Molecule ◽  
Redox Active Ligands ◽  
Redox Active

scholarly journals High-resolution cryo-EM structure of photosystem II reveals damage from high-dose electron beams

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Koji Kato ◽  
Naoyuki Miyazaki ◽  
Tasuku Hamaguchi ◽  
Yoshiki Nakajima ◽  
Fusamichi Akita ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Physiological State ◽  
High Dose ◽  
Final State ◽  
X Ray ◽  
Redox States ◽  
X Ray Crystallography ◽  
Cryo Electron Microscopy ◽  
Redox Active ◽  
Beam Damage

AbstractPhotosystem II (PSII) plays a key role in water-splitting and oxygen evolution. X-ray crystallography has revealed its atomic structure and some intermediate structures. However, these structures are in the crystalline state and its final state structure has not been solved. Here we analyzed the structure of PSII in solution at 1.95 Å resolution by single-particle cryo-electron microscopy (cryo-EM). The structure obtained is similar to the crystal structure, but a PsbY subunit was visible in the cryo-EM structure, indicating that it represents its physiological state more closely. Electron beam damage was observed at a high-dose in the regions that were easily affected by redox states, and reducing the beam dosage by reducing frames from 50 to 2 yielded a similar resolution but reduced the damage remarkably. This study will serve as a good indicator for determining damage-free cryo-EM structures of not only PSII but also all biological samples, especially redox-active metalloproteins.

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