Porphyrin molecular catalysts for selective electrochemical reduction of CO2 into CO

Patent metadata

Field	Value
Publication number	US-10125427-B2
Application number	US-201515309035-A
Country	US
Kind code	B2
Filing date	May 4, 2015
Priority date	May 5, 2014
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

The present invention relates to porphyrins of formula (I): wherein R 1 to R 6 , R 1′ to R 6′ , X, X′ Y and Y′ are as described in claim 1 . The invention also relates to complexes of said porphyrins with transition metals, in particular iron, preferably as Fe(III) or Fe(0) complex, and salts thereof, use thereof as catalysts for the selective electrochemical reduction of CO 2 into CO, electrochemical cells comprising said complexes, and a method for selectively reducing electrochemically CO 2 into CO using said complexes.

First claim

The invention claimed is:

1. A porphyrin of formula (I):

wherein
R 1 , R 1′ , R 2 and R 2′ independently represent H, OH, F, N + R 7 R 8 R 9 , C 1 -C 4 alkyl or C 1 -C 4 -alcohol,
R 3 , R 3′ , R 6 and R 6′ are independently selected from the group consisting of H, OH, F and C 1 -C 4 -alcohol,
R 4 , R 4′ , R 5 , R 5′ are independently selected from the group consisting of H, OH, F, C 1 -C 4 alkyl, C 1 -C 4 -alcohol, or N + R 7 R 8 R 9 ,
X and X′ independently represent CH, CF, CN + R 7 R 8 R 9 , or N + R 7 ,
Y and Y′ independently represent CH, CF, CN + R 7 R 8 R 9 , or N + R 7 ,
R 7 , R 8 and R 9 independently of each other represent H or a C 1 -C 4 alkyl group,
provided that at least one of X, X′, Y and Y′ represents CF, CN + R 7 R 8 R 9 , or N + R 7 , or at least one of R 3 , R 3′ , R 6 and R 6′ represents F or at least one of R 1 , R 1′ , R 2 , R 2′ , R 4 , R 4′ , R 5 , and R 5′ represents F or N + R 7 R 8 R 9 ,
and salts thereof.

2. The porphyrin of claim 1 , wherein at least one of X, X′, Y or Y′ represents CF, CN+R 7 R 8 R 9 , or N + R 7 or at least one of R 1 , R 1′ , R 2 , R 2′ , R 4 , R 4′ , R 5 , R 5′ represents F or N + R 7 R 8 R 9 , with R 7 , R 8 and R 9 are as described in claim 1 .

3. The porphyrin of claim 1 , wherein it is of formula (III):

with R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , X and Y are as defined in claim 1 .

4. The porphyrin of claim 1 , wherein X and X′ independently represent CH or CF.

5. The porphyrin of claim 1 , wherein R 3 , R 3′ , R 4 , R 4′ , R 5 , R 5′ , R 6 , and R 6′ are independently selected from the group consisting of H and F.

6. The porphyrin of claim 1 , wherein at least one of Y, Y′, X and X′ is CN + R 7 R 8 R 9 or at least one of R 1 , R 1′ , R 2 , R 2′ , R 4 , R 4′ , R 5 , and R 5′ is N + R 7 R 8 R 9 , with R 7 , R 8 and R 9 defined in claim 1 .

7. The porphyrin of claim 6 , wherein it is of the following formula:

wherein R 7 , R 8 and R 9 as independently of each other represent H or a C 1 -C 4 alkyl group.

8. The porphyrin of claim 1 , wherein it is:

9. A complex of a porphyrin according to claim 1 with a transition metal and salts thereof.

10. The complex of claim 9 , wherein the transition metal is iron.

11. An electrochemical cell comprising at least:
an electrolyte solution comprising the solvent, a supporting electrolyte, and the substrate CO 2 ,
a power supply providing the energy necessary to trigger the electrochemical reactions involving the substrate, and
two electrodes, an anode and a cathode,
wherein the electrochemical cell further comprises the complex of claim 8 .

12. The electrochemical cell of claim 11 , wherein the complex is in a concentration, in the electrolyte solution, of between 0.0005 and 0.01 M.

13. The electrochemical cell of claim 11 , wherein the electrolyte further comprises a proton donor selected from the group consisting of water (H 2 O), trifluoroethanol, phenol and acetic acid.

14. The electrochemical cell of claim 11 , wherein the complex is in the electrolyte solution.

15. A method of reducing electrochemically CO 2 into CO using the complex of claim 9 as catalyst or an electrochemical cell comprising at least:
an electrolyte solution comprising the solvent, a supporting electrolyte, and the substrate CO 2 ,
a power supply providing the energy necessary to trigger the electrochemical reactions involving the substrate,
two electrodes, an anode and a cathode, and
the complex of claim 9 .

16. The method of claim 15 , wherein the method is carried out in the presence of a proton donor.

17. The method of claim 15 , wherein the potential applied to the cathode is between −2.5 V and −0.5 V versus NHE.

18. The method of claim 15 , wherein the proton donor is selected from the group consisting of water, trifluoroethanol, phenol and acetic acid.

19. The method of claim 15 , wherein the intensity applied to the cathode is between 2 and 5 A/m 2 .

Assignees

• Centre Nat Rech Scient
• Univ Paris Diderot Paris 7

Inventors

• Costentin Cyrille
• Robert Marc
• Drouet Samuel
• Passard Guillaume
• Saveant Jean-Michel
• Tatin Arnaud

Classifications

• C25B11/12

  Chemistry & Metallurgy · mapped topic

• C25B1/00 Primary

  Electrolytic production of inorganic compounds or non-metals · CPC title

• C07D487/22 Primary

  in which the condensed system contains four or more hetero rings · CPC title

• C25B9/00

  Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features · CPC title

• C07F15/025

  without a metal-carbon linkage · CPC title