Double Hangman Iron Porphyrin and the Effect of Electrostatic Nonbonding Interactions on Carbon Dioxide Reduction

Margarit, Charles G.; Asimow, Naomi G.; Gonzalez, Miguel I.; Nocera, Daniel G.

doi:10.1021/acs.jpclett.9b03897

Cited by 51 publications

(40 citation statements)

References 75 publications

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“…Control experiments, where negatively‐charged sulfonates were incorporated in catalyst 20 , show severe decrease in the log TOF max (3.6) and increase of the overpotential ( η’ =0.74 V) due to the electrostatic repulsions between the sulfonate groups and the negatively‐charged metal carboxylate intermediate [30] . This downgraded performance was similarly observed for sulfonates and carboxylates in hangman iron‐porphyrins [36,46] …”

Section: Going Beyond Electronic Effectsmentioning

confidence: 72%

Shaping the Electrocatalytic Performance of Metal Complexes for CO₂ Reduction

et al. 2021

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The mass scale catalytic transformation of carbon dioxide (CO2) into reduced forms of carbon is an imperative to address the ever‐increasing anthropogenic emission. Understanding the mechanistic routes leading to the multi‐electron‐proton conversion of CO2 provides handles for chemists to overcome the kinetically and thermodynamically hard challenges and further optimize these processes. Through extensive electrochemical investigations, Prof. J.‐M. Savéant and coworkers have made invaluable electro‐analytical tools accessible to chemists to address and position the electrocatalytic performance of molecular catalysts grounded on a theoretical basis. Furthermore, he has bequeathed lessons to future generations on ways to improve the catalytic activity and the electrocatalytic zone we must target. As a tribute to his accomplishments, we recall here a few aspects on the tuning of iron porphyrin catalysts by playing on electronic effects, proton delivery, hydrogen bonding and electrostatic interactions and its implications to other catalytic systems.

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Section: Going Beyond Electronic Effectsmentioning

confidence: 72%

Shaping the Electrocatalytic Performance of Metal Complexes for CO₂ Reduction

et al. 2021

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“…[4] The ability to modify the surrounding ligand framework of these FeÀ porphyrin catalysts synthetically allows a simple yet effective way to systematically adjust the thermodynamics and kinetics of the reduction reaction facilitated by these complexes. [5] These structural changes can influence the potential of the reduction or affect the catalytic mechanism via stabilization of intermediates. Of note, use of a modified ligand framework bearing proton donor moieties or hydrogen bonding motifs have shown enhancement in overall catalysis, likely due to a relative increase in proton concentration at the active site mediating proton transfer.…”

Section: Introductionmentioning

confidence: 99%

An Iron Porphyrin Complex with Pendant Pyridine Substituents Facilitates Electrocatalytic CO₂Reduction via Second Coordination Sphere Effects

Ramuglia

Budhija

et al. 2021

ChemCatChem

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A bispyridylamine-based hanging unit within the ligand framework of a newly synthesized iron porphyrin complex (Py 2 XPFe) can act, on the one hand, as a hydrogen bonding site to facilitate proton transfer in catalysis and, on the other hand, as coordination site for a second Lewis acidic metal center. The bispyridylamine group in close proximity of the iron porphyrin center is able to mediate electrocatalytic CO 2 reduction in anhydrous MeCN. The hydrogen bonding interactions within the hanging group affect the kinetics of catalysis likely through stabilization of the [Fe I (CO 2 H)] À intermediate, increasing the overall rate of catalysis when compared to the non-functionalized analog, TMPFe (TMP = tetramesitylporphyrin). The rate constants (k app ) of the reduction reaction were calculated using the FOWA method which resulted in a higher TOF max for the complex Py 2 XPFe compared with TMPFe in neat MeCN (1.7 × 10 2 vs. 1.1 × 10 1 s À 1 ). The addition of weak Brønsted acids to the reaction mixture (TFE or PhOH) shows an increase in the rate of catalysis for both complexes, yet the Py 2 XPFe analog displays higher TOF max at each relative acid concentration, suggesting the hanging group beneficially impacts the rate of catalysis in the presence of these proton sources. The addition of Lewis acidic Sc 3 + to Py 2 XPFe also results in an increase in current density of the CO 2 reduction reaction. Resonance Raman as well as 1 H-NMR spectroscopy indicates coordination to the pyridine substituents.

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“…[66] Obtaining a more detailed understanding of the relative magnitude of inductive and electrostatic factors would be valuable, particularly as leveraging through-space interactions should serve as an ideal strategy to break free-energy relationships. [67][68][69][70][71][72][73] Phosphines are ideal scaffolds to quantify the influence of electrostatics as these ligands feature prominently in catalysis and have well defined parameters for their donor strength such as the Tolman Electronic Parameter (TEP). [74] Indeed, cationic and anionic functional groups have previously been incorporated into phosphines, frequently leading to distinct properties or reactivity in comparison to neutral analogues.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic vs. Inductive Effects in Phosphine Ligand Donor Properties, Reactivity, and Catalysis

Kelty¹,

McNeece²,

Filatov³

et al. 2021

Preprint

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The use of charged groups to leverage electrostatics in molecular systems is a promising strategy to tune reactivity. However, disentangling the relative influences of inductive (through-bond) and electrostatic (through-space) contributions from charged groups is a long-standing challenge. To quantify the interplay of these effects we have synthesized and analyzed the anionic phosphine, Ph2PCH2BF3−, its selenide, and its transition metal complexes. Solvent-dependent changes in donor strength consistent with Coulomb’s law support a dominant electrostatic contribution to donor strength, while computations highlight the impact of charge position and orientation. Finally, inclusion of the anion also greatly accelerates C–F oxidative addition reactivity in Ni complexes, allowing for rapid catalytic C–F borylation of fluoroarenes. These results show that covalently bound charged functionalities can exert a major electrostatic influence under common solution phase reaction conditions.

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Double Hangman Iron Porphyrin and the Effect of Electrostatic Nonbonding Interactions on Carbon Dioxide Reduction

Abstract: Experimental section. NMR, UV−vis, MS, and additional crystal structures (Figures S1−S19) (PDF) Crystallographic data (CIF)

Cited by 51 publications

References 75 publications

Shaping the Electrocatalytic Performance of Metal Complexes for CO₂ Reduction

Shaping the Electrocatalytic Performance of Metal Complexes for CO₂ Reduction

An Iron Porphyrin Complex with Pendant Pyridine Substituents Facilitates Electrocatalytic CO₂Reduction via Second Coordination Sphere Effects

Electrostatic vs. Inductive Effects in Phosphine Ligand Donor Properties, Reactivity, and Catalysis

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Double Hangman Iron Porphyrin and the Effect of Electrostatic Nonbonding Interactions on Carbon Dioxide Reduction

Abstract: Experimental section. NMR, UV−vis, MS, and additional crystal structures (Figures S1−S19) (PDF) Crystallographic data (CIF)

Cited by 51 publications

References 75 publications

Shaping the Electrocatalytic Performance of Metal Complexes for CO2 Reduction

Shaping the Electrocatalytic Performance of Metal Complexes for CO2 Reduction

An Iron Porphyrin Complex with Pendant Pyridine Substituents Facilitates Electrocatalytic CO2Reduction via Second Coordination Sphere Effects

Electrostatic vs. Inductive Effects in Phosphine Ligand Donor Properties, Reactivity, and Catalysis

Contact Info

Product

Resources

About

Shaping the Electrocatalytic Performance of Metal Complexes for CO₂ Reduction

Shaping the Electrocatalytic Performance of Metal Complexes for CO₂ Reduction

An Iron Porphyrin Complex with Pendant Pyridine Substituents Facilitates Electrocatalytic CO₂Reduction via Second Coordination Sphere Effects