Exploring the Full Potential of Photocatalytic Carbon Dioxide Reduction Using a Dinuclear Re2Cl2 Complex Assisted by Various Photosensitizers

Abstract

Summary

A photochemical reduction of CO₂ to CO was shown using the dirhenium complex (tBuxant)-(Re(bpy)(CO)3Cl)2 in combination with the ruthenium and copper photosensitizers Ir(fppy)3 and [Cu(bcp)(xant)][PF6]. Turnover numbers (TONs) of up to 270 were reached after 4 h of irradiation (λ > 400 nm) in DMF.

Advances and special progress

One of very few studies where a dinuclear catalytic system able to activate CO₂ is used in combination with photosensitizers.

Additional remarks

The experiments were performed using the rhenium complex (50 μM in DMF) as the catalyst in combination with different loadings of the sensitizers and sacrificial electron donors under 4 h of irradiation with λ > 400 nm.

Content of the published article in detail

The article contains results of a detailed study on the influence of additional photosensitizers on the catalytic performance of the dinuclear rhenium catalyst (tBuxant)-(Re(bpy)(CO)3Cl)2 for the reduction of CO₂ to CO. The catalytic system performs best (referring to the TON of CO production) for the combination of the above mentioned catalyst with the iridium complex Ir(fppy)3 as the photosensitizer in the presence of BIH/TEA as sacrificial electron donors.

Catalyst

(tBuxant)-(Re(bpy)(CO)3Cl)2

Photosensitizer

Ir(fppy)3 [Cu(bcp)(xant)][PF6]

Investigation

	cat	cat conc [µM]	PS	PS conc [mM]	e-D	e-D conc [M]	solvent A	additives	.	λexc [nm]	.	TON CO	.
1.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	TEA	0.36	DMF			> 400		52
2.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	BIH	0.005	DMF	TEA		> 400		78
3.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	BIH	0.01	DMF	TEA		> 400		195
4.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	BIH	0.01	DMF	TEA		> 400		154
5.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	BIH	0.01	DMF	TEA		> 400		131
6.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	BIH	0.02	DMF	TEA		> 400		134
7.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	BIH	0.02	DMF	TEA		> 400		193
8.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.05	BIH	0.5	DMF	TEA		> 400		255
9.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05			BIH	0.01	DMF	TEA		> 400		63
10.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.005	BIH	0.01	DMF	TEA		> 400		124
11.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.0125	BIH	0.01	DMF	TEA		> 400		144
12.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.025	BIH	0.01	DMF	TEA		> 400		149
13.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	Ir(fppy)3	0.1	BIH	0.05	DMF	TEA		> 400		270
14.	(tBuxant)-(Re(bpy)(CO)3Cl)2	0.05	[Cu(bcp)(xant)][PF6]	0.05	BIH	0.01	DMF	TEA		> 400		169

Investigation-Name: Optimizations of the conditionsExport

Sacrificial electron donor

In this study, TEA (TEA) and BIH (BIH) were used as sacrificial electron donors.