Highly Efficient and Robust Photocatalytic Systems for CO2 Reduction Consisting of a Cu(I) Photosensitizer and Mn(I) Catalysts

Abstract

Summary

A photochemical reduction of CO₂ to CO or formic acid was shown using the manganese complexes Mn(bpy)(CO)3Br (100752), (100845) or Mn(oMesbpy)(CO)2Br (100705) as catalyst in combination with the copper-based photosensitizer [Cu(phen)-(dPPh-Bu)2]2[PF6]2 (100828). Turnover numbers (TONs) over 1300 for CO were reached in dimethylacetamide/TEOA for complex (100845). The highest selectivity for CO (96%) was obtained for catalyst Mn(oMesbpy)(CO)2Br (100705) while catalyst Mn(bpy)(CO)3Br (100752) allowed for the reduction of CO₂ to formic acid with a selectivity of 74%. The experiments were conducted under visible-light irradiation (λ = 436 nm) using BIH as sacrificial reductants (see section SEDs below).

Advances and special progress

Employing catalyst (100845), the highest quantum yield for CO₂ reduction using abundant elements (57%) at that time was achieved.

Additional remarks

The authors could show that the substituents on the manganese complexes largely influenced the photocatalytic efficiency and product selectivity.

Content of the published article in detail

The article contains results for the reduction of CO₂ to CO and formic acid under visible-light catalysis using manganese complexes as catalysts. The catalytic system performs best (referring to the TON of CO production) in DMA/TEOA.

Catalyst

(100751) [Show R-Groups] Mn(oMesbpy)(CO)2Br (100705)

Photosensitizer

[Cu(phen)-(dPPh-Bu)2]2[PF6]2 (100828)

Investigation

REDIRECT Results for photocatalytic reduction of CO2Investigation-Name: Table 1

Sacrificial electron donor

In this study, the experiments were done with the sacrificial electron donors TEOA (100507) and BIH (100508).

Additives

In this study, no additives were tested.