A Bi-functional Second Coordination Sphere for Electrocatalytic CO2 Reduction: The Concerted Improvement by a Local Proton Source and Local Coulombic Interactions

2020 ◽  
Vol 49 (3) ◽  
pp. 315-317 ◽  
Author(s):  
Yasuo Matsubara ◽  
Miho Shimojima ◽  
Shohei Takagi
Keyword(s):  
Coordination Sphere ◽  
Co2 Reduction ◽  
Coulombic Interactions ◽  
Proton Source ◽  
Second Coordination Sphere

Homogeneous Electrocatalytic CO2 Reduction Using a Porphyrin Complex with Flexible Triazole Units in the Second Coordination Sphere

2021 ◽  
Vol 4 (4) ◽  
pp. 3604-3611
Author(s):  
Nilakshi Devi ◽  
Caroline K. Williams ◽  
Ashwin Chaturvedi ◽  
Jianbing “Jimmy” Jiang
Keyword(s):  
Coordination Sphere ◽  
Co2 Reduction ◽  
Porphyrin Complex ◽  
Second Coordination Sphere

Tuning Second Coordination Sphere Interactions in Polypyridyl–Iron Complexes to Achieve Selective Electrocatalytic Reduction of Carbon Dioxide to Carbon Monoxide

2019 ◽  
Author(s):  
David Zee ◽  
Michael Nippe ◽  
Amanda King ◽  
Christopher Chang ◽  
Jeffrey R. Long
Keyword(s):  
Carbon Dioxide ◽  
Coordination Sphere ◽  
Functional Group ◽  
Value Added ◽  
Acetonitrile Solution ◽  
Proton Source ◽  
Fe Complexes ◽  
Second Coordination Sphere ◽  
Functionalized Ligands ◽  
High Degree

The development of noble metal-free catalysts capable of electrochemically converting carbon dioxide (CO<sub>2</sub>) selectively into value added compounds remains one of the central challenges in sustainable energy science. Here, we present a systematic study of Fe(II) complexes of the functionalized ligands bpy<sup>R</sup>PY2Me (bpyPY2Me = 6-(1,1-di(pyridin-2-yl)ethyl)-2,2′-bipyridine) in pursuit of water-stable molecular Fe complexes that are selective for the catalytic formation of CO from CO<sub>2</sub>. Taking advantage of the inherently high degree of tunability of this ligand manifold, we followed a bio-inspired approach by installing protic functional groups of varying acidities (–H, –OH, –OMe, –NHEt, and –NEt2) into the ligand framework to systematically modify the second coordination sphere of the Fe center. This family of [(bpy<sup>R</sup>PY2Me)Fe(II)] complexes was characterized using single-crystal X-ray analysis, 1H NMR spectroscopy, and mass spectrometry. Comparative catalytic evaluation of this set of compounds via voltammetry and electrolysis experiments identified [(bpy<sup>NHEt</sup>PY2Me)Fe]<sup>2+</sup> in particular as an efficient, iron-based, non-heme CO<sub>2</sub> electro-reduction catalyst that displays significant selectivity for the conversion of CO<sub>2</sub> to CO in acetonitrile solution with 11 M H<sub>2</sub>O. We propose that the NH group acts as a local proton source for cleaving the C–O bond in CO<sub>2</sub> to form CO. Interestingly, the complex with the most acidic functional group in the second coordination sphere, [(bpy<sup>OH</sup>PY2Me)Fe]<sup>2+</sup>, favors formation of H<sub>2</sub> over CO. Our results correlate the selectivity of water versus carbon dioxide reduction to the acidity of the second coordination sphere functional group and emphasize the continued untapped potential that synthetic molecular chemistry offers in the pursuit of next-generation CO<sub>2</sub> reduction electrocatalysts.<br>

scholarly journals An iron porphyrin complex with pendant pyridine substituents facilitates electrocatalytic CO2 reduction via second coordination sphere effects

ChemCatChem ◽  
2021 ◽  
Author(s):  
Anthony Ramuglia ◽  
Hoang Khoa Ly ◽  
Vishal Budhija ◽  
Michael Marquardt ◽  
Matthias Schwalbe ◽  
...  
Keyword(s):  
Coordination Sphere ◽  
Co2 Reduction ◽  
Iron Porphyrin ◽  
Porphyrin Complex ◽  
Second Coordination Sphere

Tuning Second Coordination Sphere Interactions in Polypyridyl–Iron Complexes to Achieve Selective Electrocatalytic Reduction of Carbon Dioxide to Carbon Monoxide

2019 ◽  
Author(s):  
David Zee ◽  
Michael Nippe ◽  
Amanda King ◽  
Christopher Chang ◽  
Jeffrey R. Long
Keyword(s):  
Carbon Dioxide ◽  
Coordination Sphere ◽  
Functional Group ◽  
Value Added ◽  
Acetonitrile Solution ◽  
Proton Source ◽  
Fe Complexes ◽  
Second Coordination Sphere ◽  
Functionalized Ligands ◽  
High Degree

The development of noble metal-free catalysts capable of electrochemically converting carbon dioxide (CO<sub>2</sub>) selectively into value added compounds remains one of the central challenges in sustainable energy science. Here, we present a systematic study of Fe(II) complexes of the functionalized ligands bpy<sup>R</sup>PY2Me (bpyPY2Me = 6-(1,1-di(pyridin-2-yl)ethyl)-2,2′-bipyridine) in pursuit of water-stable molecular Fe complexes that are selective for the catalytic formation of CO from CO<sub>2</sub>. Taking advantage of the inherently high degree of tunability of this ligand manifold, we followed a bio-inspired approach by installing protic functional groups of varying acidities (–H, –OH, –OMe, –NHEt, and –NEt2) into the ligand framework to systematically modify the second coordination sphere of the Fe center. This family of [(bpy<sup>R</sup>PY2Me)Fe(II)] complexes was characterized using single-crystal X-ray analysis, 1H NMR spectroscopy, and mass spectrometry. Comparative catalytic evaluation of this set of compounds via voltammetry and electrolysis experiments identified [(bpy<sup>NHEt</sup>PY2Me)Fe]<sup>2+</sup> in particular as an efficient, iron-based, non-heme CO<sub>2</sub> electro-reduction catalyst that displays significant selectivity for the conversion of CO<sub>2</sub> to CO in acetonitrile solution with 11 M H<sub>2</sub>O. We propose that the NH group acts as a local proton source for cleaving the C–O bond in CO<sub>2</sub> to form CO. Interestingly, the complex with the most acidic functional group in the second coordination sphere, [(bpy<sup>OH</sup>PY2Me)Fe]<sup>2+</sup>, favors formation of H<sub>2</sub> over CO. Our results correlate the selectivity of water versus carbon dioxide reduction to the acidity of the second coordination sphere functional group and emphasize the continued untapped potential that synthetic molecular chemistry offers in the pursuit of next-generation CO<sub>2</sub> reduction electrocatalysts.<br>

scholarly journals Recent advances in metalloporphyrin-based catalyst design towards carbon dioxide reduction: from bio-inspired second coordination sphere modifications to hierarchical architectures

2020 ◽  
Vol 49 (8) ◽  
pp. 2381-2396 ◽  
Author(s):  
Philipp Gotico ◽  
Zakaria Halime ◽  
Ally Aukauloo
Keyword(s):  
Carbon Dioxide ◽  
Coordination Sphere ◽  
Three Dimensional ◽  
Carbon Dioxide Reduction ◽  
Catalyst Design ◽  
Recent Advances ◽  
Hierarchical Architectures ◽  
Second Coordination Sphere

The progress in CO2 reduction catalyst design was examined starting from simple metalloporphyrin structures and progressing to three-dimensional active architectures.

scholarly journals An amide-based second coordination sphere promotes the dimer pathway of Mn-catalyzed CO2-to-CO reduction at low overpotential

2021 ◽  
Vol 12 (13) ◽  
pp. 4779-4788
Author(s):  
Yong Yang ◽  
Mehmed Z. Ertem ◽  
Lele Duan
Keyword(s):  
Coordination Sphere ◽  
Bond Cleavage ◽  
Low Overpotential ◽  
Second Coordination Sphere ◽  
Co Reduction ◽  
Reduction Catalysts

The amide NH group decreases the overpotential of Mn-based CO2 reduction catalysts by promoting the dimer and protonation-first pathways in the presence of H2O and enhances the CO2 electroreduction activity by facilitating C–OH bond cleavage.

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