Intramolecular Electrostatic Effects on O2, CO2, and Acetate Binding to a Cationic Iron Porphyrin

We present a bioinspired strategy for enhancing electrochemical carbon dioxide reduction catalysis by cooperative use of base-metal molecular catalysts with intermolecular second-sphere redox mediators that facilitate both electron and proton transfer. Functional synthetic mimics of the biological redox cofactor NADH, which are electrochemically stable and are capable of mediating both electron and proton transfer, can enhance the activity of an iron porphyrin catalyst for electrochemical reduction of CO2 to CO, achieving a 13-fold rate improvement without altering the intrinsic high selectivity of this catalyst platform for CO2 versus proton reduction. Evaluation of a systematic series of NADH analogs and redox-inactive control additives with varying proton and electron reservoir properties reveals that both electron and proton transfer contribute to the observed catalytic enhancements. This work establishes that second-sphere dual control of electron and proton inventories is a viable design strategy for developing more effective electrocatalysts for CO2 reduction, providing a starting point for broader applications of this approach to other multi-electron, multi-proton transformations.

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Electrostatics. Methods for simulation of electrostatic effects

10.3403/02595104 ◽

2002 ◽

Keyword(s):

Electrostatic Effects

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Human Orosomucoid: Dissociation of Tyrosines in the Systems Water-Low Aliphatic Alcohol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19971533 ◽

1997 ◽

Vol 62 (10) ◽

pp. 1533-1543

Author(s):

Vladimír Karpenko ◽

Jana Horálková ◽

Milan Kodíček

Keyword(s):

Human Serum ◽

Systems Analysis ◽

Titration Curve ◽

Relative Permittivity ◽

Structural Changes ◽

Aliphatic Alcohol ◽

Mixed Media ◽

Spectrophotometric Titration ◽

Electrostatic Effects

The influence of methanol, ethanol, propan-1-ol, and propan-2-ol on the dissociation of tyrosines of human serum orosomucoid (acid α1-glycoprotein) was studied. The content of alcohols was chosen so that their solutions had the same value of the relative permittivity. Then, the contribution of electrostatic effects was equal in all cases and the observed differences between aqueous and alcoholic solutions reflected other, nonelectrostatic effects in the studied systems. Analysis of the spectrophotometric titration curve revealed three kinds of tyrosine groups (n1, n2, n3), but only the values pK1 and pK2 could be calculated. The observed differences of pK values in aqueous and mixed media are discussed and compared with the structural changes of the orosomucoid molecule.

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Aliphatic hydroxylation catalyzed by iron porphyrin complexes

Journal of the American Chemical Society ◽

10.1021/ja00358a009 ◽

1983 ◽

Vol 105 (20) ◽

pp. 6243-6248 ◽

Cited By ~ 283

Author(s):

John T. Groves ◽

Thomas E. Nemo

Keyword(s):

Iron Porphyrin ◽

Iron Porphyrin Complexes

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Using internal electrostatic fields to manipulate the valence manifolds of copper complexes

Chemical Science ◽

10.1039/d0sc06364a ◽

2021 ◽

Author(s):

Alexander B. Weberg ◽

Samuel P. McCollom ◽

Laura M. Thierer ◽

Michael R. Gau ◽

Patrick J. Carroll ◽

...

Keyword(s):

Coordination Sphere ◽

Copper Complexes ◽

Photophysical Properties ◽

Redox Potentials ◽

Electrostatic Effects ◽

Electrostatic Fields ◽

Secondary Coordination Sphere

Secondary coordination sphere electrostatic effects tune the valence manifolds of copper centers, impacting molecular geometries, photophysical properties, and redox potentials.

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