Exchange Coupling Determines Metal-Dependent Efficiency for Iron- and Cobalt-Catalyzed Photochemical CO2 Reduction

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DOI 10.1021/acscatal.2c02072
Authors Patricia De La Torre, Jeffrey S. Derrick, Andrew Snider, Peter T. Smith, Matthias Loipersberger, Martin Head-Gordon, Christopher J. Chang,
Submitted 01.07.2022
Published online 01.07.2022
Licenses https://doi.org/10.15223/policy-029, https://doi.org/10.15223/policy-037, https://doi.org/10.15223/policy-045,
Subjects -
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Abstract

Summary

A photochemical reduction of CO2 to CO was shown using an Fe2+ and Co2+ complex as catalysts in combination with different photosensitizers. The authors examined the efficiency for photocatalytic CO2RR pending on metal−ligand exchange coupling as an example of charge delocalization. The iron complex (100968) and cobalt complexes (100969), both bearing the redox-active ligand tpyPY2Me were tested in comparison. It was found that the two-electron reduction of the Co(tpyPY2Me)]2+ catalyst (100969) occurs at potentials 770 mV more negative than the Fe(tpyPY2Me)]2+ analogue (100968) due to maximizing the exchange coupling in the latter compound.

Advances and special progress

Additional remarks

Content of the published article in detail

Catalysts tested in this study

(100968) (100969)

Photosensitizer

Ru(bpy)3 (100680) 3,6-Diamino-10-methylacridinium (100970) (100971) Ir(ppy)3 (100843)

Investigation

General details for the experimental setup: Conducted inside a 25 mL borosilicate culture tube with a stir bar, a rubber septum, and an aluminum crimped top. The reaction vessel contained 5 mL of CH3CN, 2 μM of the catalyst, 200 μM of the photosensitizer, 100 mM BIH (112 mg), and 1 M phenol (470 mg). The reaction tubes were sparged with CO2 for 10 min, followed by injection of a gaseous internal standard (0.1 mL of C2H6). The reactions were placed on a stirplate 13 cm from two Kessil blue LED lamps (440 nm) for 15 or 30 min at a time and maintained at ambient temperature using a fan. Analysis of the headspace by Gas Chromatography (GC).

catcat conc [µM]PSPS conc [mM]e-De-D conc [M]..solvent Aadditives..TON COTON H2...
(edit)1.Molecule:100968 2Ru(bpy)30.2BIH0.1MeCN1552086
(edit)2.Molecule:100968 0.2Ru(bpy)30.2BIH0.1MeCN303491013
(edit)3.Ru(bpy)30.2BIH0.1MeCN4352
(edit)4.Molecule:100968 2BIH0.1MeCN1120
(edit)5.Molecule:100968 2Ru(bpy)30.2MeCN1500
(edit)6.Molecule:100968 2Ru(bpy)30.2BIH0.1MeCN60
(edit)7.Molecule:100968 2Ru(bpy)30.2BIH0.1MeCNAr0222
(edit)8.Molecule:100968 2Molecule:100971 0.2BIH0.1MeCN12749163
(edit)9.Molecule:100968 0.2Molecule:100971 0.2BIH0.1MeCN287126527
(edit)10.Molecule:100968 2Ir(ppy)30.2BIH0.1MeCN18502141
(edit)11.Molecule:100968 2Molecule:100970 0.2BIH0.1MeCN67100

Investigation-Name: CO2 Reduction under diverse conditions with diverse sensitizers

The values in Table 2 include TOF numbers given in TON/h

"Molecule:" can not be assigned to a declared number type with value 100973."Molecule:" can not be assigned to a declared number type with value 100974."Molecule:" can not be assigned to a declared number type with value 100975.<ul><li>"Molecule:" can not be assigned to a declared number type with value 100976.</li> <!--br--><li>"Molecule:" can not be assigned to a declared number type with value 1009792.</li></ul><ul><li>"Molecule:" can not be assigned to a declared number type with value 100977.</li> <!--br--><li>"Molecule:" can not be assigned to a declared number type with value 1009819.</li></ul>"Molecule:" can not be assigned to a declared number type with value 100978."Molecule:" can not be assigned to a declared number type with value 100979."Molecule:" can not be assigned to a declared number type with value 100980."Molecule:" can not be assigned to a declared number type with value 100981.

catcat conc [µM]PSPS conc [mM]e-De-D conc [M]..solvent A.......
(edit)1.Molecule:100969 2Ru(bpy)30.2BIH0.1MeCN
(edit)2.Molecule:100969 2Molecule:100971 0.2BIH0.1MeCN
(edit)3.Molecule:100969 2Ir(ppy)30.2BIH0.05MeCN
(edit)4.Molecule:100969 2Molecule:100971 0.2BIH0.05MeCN
(edit)5.Molecule:100969 2Ru(bpy)30.2BIH0.05MeCN
(edit)6.Molecule:100969 2Molecule:100971 0.2TEA0.05MeCN
(edit)7.Molecule:100969 2Molecule:100971 0.2TEA0.05MeCN
(edit)8.Molecule:100969 2Molecule:100971 0.2TEA0.05MeCN
(edit)9.Molecule:100969 2Molecule:100971 0.2TEA0.05MeCN

Investigation-Name: Table 2_Conversion with Co catalyst

Further Information

The results for the catalytic activity of the Co2+ compound (100969) in Table 2 were gained from the Supporting Information.

Sacrificial electron donor

In this study, the experiments were done with the sacrificial electron donor BIH (100508).

Additives

Different sources of protons were used, e.g. PhOH (100617), TFE (100618) and 4-CHLOROPHENOL (100972)

Investigations

Tags

TagContains tags that describe the content of the page.: photocatalytic CO2 reduction (Ontology: voc4cat, OBOID: voc4cat:0000099), TagContains tags that describe the content of the page.: CO