Electrocatalytic Reduction of Carbon Dioxide by Mn(CN)(2,2′-bipyridine)(CO)<sub>3</sub>: CN Coordination Alters Mechanism

Machan, Charles W.; Stanton, Charles J.; Vandezande, Jonathon E.; Majetich, George; Schaefer, Henry F.; Kubiak, Clifford P.; Agarwal, Jay

doi:10.1021/acs.inorgchem.5b01715

Cited by 80 publications

(79 citation statements)

References 59 publications

(138 reference statements)

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“…In contrast, molecular catalysts show propensity to form a single, typically 2–4 e – CO 2 reduction products 7–23. Cobalt phthalocyanine ( CoPc ) is a well-known molecular CO 2 RR catalyst 24–32.…”

Section: Introductionmentioning

confidence: 99%

Polymer coordination promotes selective CO₂reduction by cobalt phthalocyanine

2016

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Section: Introductionmentioning

confidence: 99%

Polymer coordination promotes selective CO₂reduction by cobalt phthalocyanine

2016

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“…Indeed, structural variations of the molecular complex introduced, for instance, through synthetic modification of the ligands can allow finetuning of the complex reactivity, as well as understanding of the key steric and electronic effects on operating mechanism, product selectivity, and catalytic efficiency. 8,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Up to date, very few studies have characterized the effects of ligand substituents on the performances of a given class of molecular CO 2 reduction catalysts, based on a significant set of representatives. [18][19][20][25][26][27][28][29][30] Product selectivity in CO 2 reduction is one of the most important issues to be addressed.…”

Section: Introductionmentioning

confidence: 99%

Controlling Hydrogen Evolution during Photoreduction of CO₂ to Formic Acid Using [Rh(R-bpy)(Cp*)Cl]⁺ Catalysts: A Structure–Activity Study

et al. 2019

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The photochemical CO 2 reduction to formic acid catalyzed by a series of [Rh(4,4′-R-bpy)(Cp*)Cl] + and [Rh(5,5′-COOH-bpy)(Cp*)Cl] + complexes (Cp* = pentamethylcyclopentadienyl, bpy = 2,2′-bipyridine, R = OCH 3 , CH 3 , H, COOC 2 H 5 , CF 3 , NH 2 and COOH) was studied in order to assess how modifications in the electronic structure of the catalyst affect its selectivity, defined as the HCOOH : H 2 product ratio. A direct molecular-level influence of the functional group on the initial reaction rate for CO 2 vs. proton reduction reactions was established. Density functional theory computations elucidated for the first time the respective role of the [RhH] vs [Cp*H] tautomers, recognizing the rhodium hydride as the key player for both reactions. In particular, our calculations explain the observed tendency of electron-donating substituents to favor CO 2 reduction by means of lowering the hydricity of the Rh-H bond, resulting in lower hydride transfer barrier towards formic acid production as compared to substituents with electron-withdrawing nature that favor more strongly the proton reduction to hydrogen. ASSOCIATED CONTENT Supporting Information. Supporting electrochemical data (Figures S1-S2), photochemical experiments (Figures S3-S9), FT-IR spectra (S10-S17), computational details and Cartesian coordinates of all the species involved. This material is available free of charge via the Internet at http://pubs.acs.org.

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“…Two mechanisms have been proposed 10,[14][15][16][17][18] for the ultimate reduction of [Mn(CO) 3 ( -diimine)] 2 in the presence of CO 2 , which can be referred to as the anionic, and the oxidative addition 19 pathways. The anionic pathway involves reduction of the dimer [Mn(CO) 3 ( -diimine)] 2 at a more negative potential than the parent complex generating the five-coordinate anion [Mn(CO) 3 ( -diimine)] to which CO 2 coordinates and is catalyti-cally reduced in the presence of a Brönsted acid (the source of H + ).…”

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Manganese Tricarbonyl Complexes with Asymmetric 2-Iminopyridine Ligands: Toward Decoupling Steric and Electronic Factors in Electrocatalytic CO₂ Reduction

et al. 2016

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Manganese tricarbonyl bromide complexes incorporating IP (2-[(phenylimino)]pyridine) derivatives, [MnBr(CO) 3 (IP)], are demonstrated as a new group of catalysts for CO 2 reduction, which represent the first example of utilization of phenylimino pyridine ligands on manganese centers for this purpose. The key feature is the asymmetric structure of the redox non-innocent ligand that permits independent tuning of its steric and electronic properties. The -diimine ligands and five new Mn(I) compounds have been synthesized, isolated in high yields and fully characterized, including X-ray crystallography. Their electrochemical and electrocatalytic behavior was investigated using cyclic voltammetry and UV-vis /IR spectroelectrochemistry within an OTTLE cell. Mechanistic investigations under an inert atmosphere have revealed differences in the nature of the reduction products as a function of steric bulk of the ligand. The direct ECE (electrochemical-chemical-electrochemical) formation of a five-coordinate anion [Mn(CO) 3 (IP)] -, a product of 2-electron reduction of the parent complex, is observed in case of the bulky The interest in solar fuels in terms of both photocatalytic and electrocatalytic CO 2 reduction 1 , in the latter case utilizing sustainable electricity, has been increasing markedly in the new millennium. The recent demonstration of the electrocatalytic activity of manganese 2 analogues of the archetypal Re(I) catalysts 3,4,5,6 for CO 2 reduction has given a new impetus to research into noble-metal-free catalytic systems. [MnBr(CO) 3 ( -diimine)] complexes have been shown to outperform rhenium-based analogues with regard to CO 2 reduction under certain conditions. 7 Most notably, the presence of a Brönsted acid 7-10 appears to be a prerequisite for catalysis with a range of tricarbonyl Mndiimine complexes. Mechanistic studies 5,10 of the active 2,2 -bipyridine-based (Rbpy) manganese catalysts have shown that one-electron reduction of the parent complex [MnBr(CO) 3 (R-bpy)] precursor results in the formation of the Mn Mn dimer [Mn(CO) 3 (Rbpy)] 2 . 8,9 Notably, neither the primary reduction product [MnBr(CO) 3 (R-bpy )] nor the five-coordinate radical intermediates [Mn(CO) 3 (R-bpy)] have been detected by either UV-vis or IR spectroscopy. 2,7 Nanosecond time-resolved infrared (TRIR) studies reveal that no detectable solvent adduct is formed before the dimerization of Mn species on this timescale; instead, the five-coordinate species is observed, which rapidly dimerises. 10 For some of the Re analogues, a one-electron reduced complex, [ReCl(CO) 3 (R-bpy )] was observed by IR spectroscopy and identified by the ca. 15-20 cm -1 decrease in the (CO) energy, 11,12,13 as was the five-coordinate radical [Re(CO) 3 ( t Bubpy)] by an additional 15-20 cm -1 shift .Two mechanisms have been proposed 10,14-18 for the ultimate reduction of [Mn(CO) 3 ( -diimine)] 2 in the presence of CO 2 , which can be referred to as the anionic, and the oxidative addition 19 pathways. The anionic pathway involves reduction of ...

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Electrocatalytic Reduction of Carbon Dioxide by Mn(CN)(2,2′-bipyridine)(CO)₃: CN Coordination Alters Mechanism

Cited by 80 publications

References 59 publications

Polymer coordination promotes selective CO₂reduction by cobalt phthalocyanine

Polymer coordination promotes selective CO₂reduction by cobalt phthalocyanine

Controlling Hydrogen Evolution during Photoreduction of CO₂ to Formic Acid Using [Rh(R-bpy)(Cp*)Cl]⁺ Catalysts: A Structure–Activity Study

Manganese Tricarbonyl Complexes with Asymmetric 2-Iminopyridine Ligands: Toward Decoupling Steric and Electronic Factors in Electrocatalytic CO₂ Reduction

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Electrocatalytic Reduction of Carbon Dioxide by Mn(CN)(2,2′-bipyridine)(CO)3: CN Coordination Alters Mechanism

Cited by 80 publications

References 59 publications

Polymer coordination promotes selective CO2reduction by cobalt phthalocyanine

Polymer coordination promotes selective CO2reduction by cobalt phthalocyanine

Controlling Hydrogen Evolution during Photoreduction of CO2 to Formic Acid Using [Rh(R-bpy)(Cp*)Cl]+ Catalysts: A Structure–Activity Study

Manganese Tricarbonyl Complexes with Asymmetric 2-Iminopyridine Ligands: Toward Decoupling Steric and Electronic Factors in Electrocatalytic CO2 Reduction

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Electrocatalytic Reduction of Carbon Dioxide by Mn(CN)(2,2′-bipyridine)(CO)₃: CN Coordination Alters Mechanism

Polymer coordination promotes selective CO₂reduction by cobalt phthalocyanine

Polymer coordination promotes selective CO₂reduction by cobalt phthalocyanine

Controlling Hydrogen Evolution during Photoreduction of CO₂ to Formic Acid Using [Rh(R-bpy)(Cp*)Cl]⁺ Catalysts: A Structure–Activity Study

Manganese Tricarbonyl Complexes with Asymmetric 2-Iminopyridine Ligands: Toward Decoupling Steric and Electronic Factors in Electrocatalytic CO₂ Reduction