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

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Abstract

Summary

A photochemical reduction of CO2 to CO was shown using an Fe2+ and Co2+ complexes as catalysts in combination with Ruxx as photosensitizer.

metal−ligand exchange coupling as an example of charge delocalization that can determine the efficiency for photocatalytic CO2RR. A comparative evaluation of iron and cobalt complexes supported by the redox-active ligand tpyPY2Me establishes that the two-electron reduction of [Co(tpyPY2Me)]2+ ([Co]2+) occurs at potentials 770 mV more negative than the [Fe(tpyPY2Me)]2+ ([Fe]2+) analogue by 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 3,6-Diamino-10-methylacridinium 100971 Ir(ppy)3

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..
1.

Molecule:100968

2

Ru(bpy)3

0.2

BIH

0.1

MeCN

1552086
2.

Molecule:100968

0.2

Ru(bpy)3

0.2

BIH

0.1

MeCN

303491013
3.


Ru(bpy)3

0.2

BIH

0.1

MeCN

4352
4.

Molecule:100968

2


BIH

0.1

MeCN

1120
5.

Molecule:100968

2

Ru(bpy)3

0.2


MeCN

1500
6.

Molecule:100968

2

Ru(bpy)3

0.2

BIH

0.1

MeCN

60
7.

Molecule:100968

2

Ru(bpy)3

0.2

BIH

0.1

MeCN

Ar0222
8.

Molecule:100968

2

Molecule:100971

0.2

BIH

0.1

MeCN

12749163
9.

Molecule:100968

0.2

Molecule:100971

0.2

BIH

0.1

MeCN

287126527
10.

Molecule:100968

2

Ir(ppy)3

0.2

BIH

0.1

MeCN

18502141
11.

Molecule:100968

2

Molecule:100970

0.2

BIH

0.1

MeCN

67100
catcat conc [µM]PSPS conc [mM]e-De-D conc [M]..solvent Aadditives..TON COTON H2..
1.

Molecule:100968

2

Ru(bpy)3

0.2

BIH

0.1

MeCN

1552086
2.

Molecule:100968

0.2

Ru(bpy)3

0.2

BIH

0.1

MeCN

303491013
3.


Ru(bpy)3

0.2

BIH

0.1

MeCN

4352
4.

Molecule:100968

2


BIH

0.1

MeCN

1120
5.

Molecule:100968

2

Ru(bpy)3

0.2


MeCN

1500
6.

Molecule:100968

2

Ru(bpy)3

0.2

BIH

0.1

MeCN

60
7.

Molecule:100968

2

Ru(bpy)3

0.2

BIH

0.1

MeCN

Ar0222
8.

Molecule:100968

2

Molecule:100971

0.2

BIH

0.1

MeCN

12749163
9.

Molecule:100968

0.2

Molecule:100971

0.2

BIH

0.1

MeCN

287126527
10.

Molecule:100968

2

Ir(ppy)3

0.2

BIH

0.1

MeCN

18502141
11.

Molecule:100968

2

Molecule:100970

0.2

BIH

0.1

MeCN

67100


Further Information

The results for the catalytic activity of the Co2+ compound100969 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

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