Iridium complexes for electrocatalysis

Patent metadata

Field	Value
Publication number	US-9790605-B2
Application number	US-201414317906-A
Country	US
Kind code	B2
Filing date	Jun 27, 2014
Priority date	Jun 27, 2013
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Solution-phase (e.g., homogeneous) or surface-immobilized (e.g., heterogeneous) electrode-driven oxidation catalysts based on iridium coordination compounds which self-assemble upon chemical or electrochemical oxidation of suitable precursors and methods of making and using thereof are. Iridium species such as {[Ir(LX) x (H 2 O) y (μ-O)] z m+ } n wherein x, y, m are integers from 0-4, z and n from 1-4 and LX is an oxidation-resistant chelate ligand or ligands, such as such as 2(2-pyridyl)-2-propanolate, form upon oxidation of various molecular iridium complexes, for instance [Cp*Ir(LX)OH] or [(cod)Ir(LX)] (Cp*=pentamethylcyclopentadienyl, cod=cis-cis,1,5-cyclooctadiene) when exposed to oxidative conditions, such as sodium periodate (NaIO 4 ) in aqueous solution at ambient conditions.

First claim

We claim:

1. A compound of Formula (I)
{[Ir(LX) x (H 2 O) y (μ-O)] z m+ } n   (I),

wherein x, y, m are integers independently selected from 0, 1, 2, 3, and 4, z is an integer selected from 1, 2, 3, and 4, n is an integer selected from 2 and 4, and LX is an oxidation-resistant chelate ligand.

2. The compound of claim 1 , wherein x is 1-2, y is 1-2, m is 1-2, and z is 1-2.

3. The compound of claim 1 , wherein x is 1, y is 2, m is 2, and z is 1 or 2.

4. The compound of claim 1 , wherein z=2.

5. The compound of claim 4 , wherein LX is selected from the group consisting of 2-(2-pyridyl)-2-propanolate, 2,2′-bipyridine; 2-phenylpyridine, picolinate and combinations thereof.

6. The compound of claim 1 , wherein LX is a monodentate, bidentate, or tridentate ligand.

7. The compound of claim 6 , wherein LX is one or more N-heterocyclic carbenes, pyridines, alkoxides, carboxylates, amides, phosphine oxides, and amino alkoxides.

8. The compound of claim 6 , wherein LX is 2(2-pyridyl)-2-propanolate.

9. The compound of claim 6 , wherein LX is 2,2′-bipyridine.

10. A method for reducing organic species by electrolysis, the method comprising contacting the organic species to be reduced with the compound of claim 1 .

11. A method for reducing oxygen to water in an electrochemical fuel cell, oxygen detector or oxygen scavenging device, the method comprising contacting oxygen with the compound of claim 1 .

12. A method of making the compound of Formula (I):
{[Ir(LX) x (H 2 O) y (μ-O)] z m+ } n   (I),

wherein x, y, m are integers independently selected from 0, 1, 2, 3, and 4, z is an integer selected from 1, 2, 3, and 4, n is an integer selected from 2 and 4, and LX is an oxidation-resistant chelate ligand, comprising:
oxidizing a compound of Formula (II)
(PHL)Ir(LX)(OH) w   (II),

wherein LX is an oxidation-resistant chelate ligand, PHL is a placeholder ligand, and w is an integer selected from 0, 1, 2 and 3.

13. The method of claim 12 , wherein the compound of Formula (II) is selected from the group consisting of [(PHL)Ir(LX)OH], [(PHL)Ir(LX)], and combinations thereof.

14. The method of claim 12 , wherein the placeholder ligand comprises pentamethylcyclopentadienyl, cyclopentadienyl, phenylcyclopentadienyl, indenyl, (meth)allyl, 1,5-cyclooctadiene, 2,5-norbornadiene, cyclooctene, ethylene, and carbon monoxide.

15. A system comprising a substrate and a compound of Formula (I)
{[Ir(LX) x (H 2 O) y (μ-O)] z m+ } n   (I),

wherein x, y, m are integers independently selected from 0, 1, 2, 3, and 4, z is an integer selected from 1, 2, 3, and 4, n is an integer selected from 2 and 4, and LX is an oxidation-resistant chelate ligand
wherein the compound of Formula (I) is preparable by a method comprising:
oxidizing a compound of Formula (II)
(PHL)Ir(LX)(OH) w   (II),

wherein LX is an oxidation-resistant chelate ligand, PHL is a placeholder ligand, and w is an integer selected from 0, 1, 2 and 3.

16. The system of claim 15 , wherein the compound is in the form of a monolayer bonded to the surface of the substrate.

17. The system of claim 16 , wherein the monolayer is physically and chemically stable.

18. The system of claim 17 , wherein the catalyst retains its catalytic activity.

19. The system of claim 15 , wherein the compound of Formula (II) is selected from the group consisting of [(PHL)Ir(LX)OH], [(PHL)Ir(LX)], and combinations thereof.

20. The system of claim 15 , wherein the placeholder ligand comprises pentamethylcyclopentadienyl, cyclopentadienyl, phenylcyclopentadienyl, indenyl, (meth)allyl, 1,5-cyclooctadiene, 2,5-norbornadiene, cyclooctene, ethylene, and carbon monoxide.

21. The system of claim 15 , wherein the substrate comprises one or more allotropes of carbon, metal oxide, mixed-metal oxide, conductive polymers or combinations thereof.

22. The system of claim 21 , wherein the one or more allotropes of carbon is selected from carbon fiber, glassy carbon, carbon wool, graphene, amorphous carbon, nanotubes, and mixtures thereof.

23. The system of claim 21 , wherein the metal oxide, mixed metal oxide, or both are a conductive oxide.

24. The system of claim 23 , wherein the conductive oxide is tin-doped indium oxide.

25. The system of 21 , wherein the metal oxide, mixed metal oxide, or both are a photocatalytic oxide.

26. The system of claim 25 , wherein the photocatalytic oxide is selected from the group consisting of titanium dioxide, iron oxide, tungsten trioxide, and combinations thereof.

27. A method of performing an oxidation, the method comprising contacting a compound of Formula (I)
{[Ir(LX) x (H 2 O) y (μ-O)] z m+ } n   (I),

wherein x, y, m are integers independently selected from 0, 1, 2, 3, and 4, z is an integer selected from 1, 2, 3, and 4, n is an integer selected from 2 and 4, and LX is an oxidation-resistant chelate ligand;
with an oxidizable substrate.

28. The method of claim 27 , wherein the oxidizable substrate is water.

29. The method of claim 27 , wherein the oxidizable substrate contains an oxygen-hydrogen, carbon-hydrogen, and/or nitrogen-hydrogen bond,
wherein the oxygen-hydrogen, carbon-hydrogen, and/or nitrogen-hydrogen bond is oxidized.

30. The method of claim 27 , wherein the oxidizable substrate is a halide ion.

31. The method of claim 27 , wherein the oxidizable substrate is organic waste material.

32. The method of claim 27 , wherein the contacting is carried out in the presence of a chemical oxidant, an electrochemical potential, or electromagnetic radiation.

33. A method of depositing iridium oxide on a substrate, the method comprising combining a compound of Formula (I):
{[Ir(LX) x (H 2 O) y (μ-O)] z m+ } n   (I),

wherein x, y, m are integers independently selected from 0, 1, 2, 3, and 4, z is an integer selected from 1, 2, 3, and 4, n is an integer selected from 2 and 4, and LX is an oxidation-resistant chelate ligand, or
a compound of Formula (II)
(PHL)Ir(LX)(OH) w   (II),

wherein LX is an oxidation-resistant chelate ligand, PHL is a placeholder ligand, and w is an integer selected from 0, 1, 2 and 3,
with a substrate under conditions suitable to deposit iridium oxide.

34. The method of claim 33 , wherein the conditions suitable to deposit iridium oxide include heat, electromagnetic radiation or strong acid.

35. The method of claim 33 , wherein the iridium oxide is reduced to iridium metal.

Assignees

• Univ Yale

Inventors

• Sheehan Stafford Wheeler
• Hintermair Ulrich
• Thomsen Julianne M
• Brudvig Gary W
• Crabtree Robert H

Classifications

• Y02W10/30

  Wastewater or sewage treatment systems using renewable energies · CPC title

• C07F15/0033

  Iridium compounds · CPC title

• C25B1/003

  Chemistry & Metallurgy · mapped topic

• C25B11/0489 Primary

  Chemistry & Metallurgy · mapped topic

• C07C303/32

  of salts of sulfonic acids · CPC title