Electrochromic salts, solutions, and devices

• US 20030234379A1
• Filed: 06/20/2002
• Published: 12/25/2003
• Est. Priority Date: 06/20/2002
• Status: Active Grant

• Current Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Original Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Inventors: Burrell, Anthony K., Warner, Benjamin P., McClesky, T. Mark
• Granted Patent: US 7,064,212 B2
• Time in Patent Office: Days
• US Class Current: 252/62.2
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• CPC Class Codes: C09K 2211/1044 containing two nitrogen atoms as heteroatoms
• CPC Class Codes: C09K 2211/1059 containing three nitrogen atoms as heteroatoms
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: H01G 11/02 using combined reduction-oxidation reactions, e.g. redox arrangement or solion
• CPC Class Codes: H01G 11/62 characterised by the solute, e.g. salts, anions or cations therein
• CPC Class Codes: H01G 9/145 Liquid electrolytic capacitors H01G11/00 takes precedence
• CPC Class Codes: H01G 9/22 Devices using combined reduction and oxidation, e.g. redox arrangement or solion
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.

Claims

1. An electrochromic salt having the chemical formula

[A][B]₂

wherein B is selected from the group consisting of

bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide and wherein A is a dication having the structural formula

wherein R₁ and R₁′

are independently selected from alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

wherein R₂, R_2′

, R₃ and R_3′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₄ and R₄′

are independently selected from alkyl having 1-20 carbons;

wherein R₅, R_5′

, R₆, R_6′

, R₇, R_7′

, R₈, and R_8′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein n is 2-7;

wherein R₉ and R_9′

are independently selected from alkyl having 1-20 carbons;

wherein R₁₀, R_10′

, R₁₁, R_11′

, R₁₂, and R_12′

independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₁₃, R_13′

, R₁₄, R_14′

, R₁₅, R_15′

, R₁₆, and R_16′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₁₇ and R₁₈ are independently selected from alkyl having 1-20 carbons, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

wherein R₁₉, R₂₀, R₂₁, R₂₂, and R₂₃ are independently selected from alkyl having 1-20 carbons, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons.

2. The salt of claim 1, wherein said salt comprises an isolated salt.

3. The salt of claim 2, wherein A is a dication having the structural formula

4. The salt of claim 3, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁ and R_1′

are independently selected from alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20 carbons.

5. The salt of claim 4, wherein R₂═

R₂′

=R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from the group consisting of alkyl having 1-9 carbons, aryl, and alkyl substituted aryl having 7-20.

6. The salt of claim 5, wherein R₂ R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from methyl and benzyl.

7. An electrolyte solution for an electrochromic device, comprising:

(a) a molten salt solvent comprising at least one anion selected from the group consisting of bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide;

(b) at least one reductant soluble in said molten salt solvent; and

(c) at least one oxidant soluble in said molten salt solvent, said oxidant having the chemical formula [A][B]₂ wherein B is selected from the group consisting of bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide and wherein A is a dication having the structural formula

wherein R₁ and R₁′

are independently selected from alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

wherein R₂, R_2′

, R₃ and R_3′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₄ and R₄′

are independently selected from alkyl having 1-20 carbons;

wherein R₅, R_5′

, R₆, R_6′

, R₇, R_7′

, R₈, and R_8′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein n is 2-7;

wherein R₉ and R_9′

are independently selected from alkyl having 1-20 carbons;

wherein R₁₀, R_10′

, R₁₁, R_11′

, R₁₂, and R_12′

independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₁₃, R_13′

, R₁₄, R_14′

, R₁₅, R_15′

, R₁₆, and R_16′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₁₇ and R₁₈ are independently selected from alkyl having 1-20 carbons, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

wherein R₁₉, R₂₀, R₂₁, R₂₂, and R₂₃ are independently selected from alkyl having 1-20 carbons, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons.

8. The electrolyte solution of claim 7, wherein A is a dication having the structural formula

9. The electrolyte solution of claim 8, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁ and R_1′

are independently selected from alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20 carbons.

10. The electrolyte solution of claim 9, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from the group consisting of alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20.

11. The electrolyte solution of claim 10, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from methyl and benzyl.

12. The electrolyte solution of claim 7, wherein said reductant is selected from the group consisting of N,N,N′

,N′

-tetramethyl-p-phenylenediamine, 2,5,10-trimethyl-3-phenyl-5,10-dihydrophenazine, 5-ethyl-10-methyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrobenzo(A)phenazine, 2,7-diphenoxy-5,10-dimethyl-5,10-dihydrophenazine, 2-phenoxy-5,10-dimethyl-5,10-dihydrophenazine, 2,7-bis(o-tolyl)-5,10-dimethyl-5,10-dihydrophenazine,2,3-dimethyl-7-trifluoromethyl-5,10-diethyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrophenazine, 2,3-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2,7-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2-vinyl-5,10-dimethyl-5,10-dihydrophenazine, 2-phenyl-5,10-dimethyl-5,10-dihydrophenazine, 5,10-diisopropyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrodibenzo(A,C)phenazine, 1,5,10-trimethyl-2-phenyl-5,10-dihydrophenazin, 2,3,5,10-tetramethyl-7-trifluoromethyl-5,10-dihydrophenazine, 2,3,5,10-tetramethyl-5,10-dihydrobenzo(B)phenazine, ferrocene, 1,1′

-dimethylferrocene, and decamethylferrocene.

13. The electrolyte solution of claim 7, wherein said electrolyte solution does not include chloride, bromide, iodide, perchlorate, tetrafluoroborate, tetraphenylborate, carboxylate, carbonate, hexafluorophosphate, or hexafluoroantimonate anions.

14. The electrolyte solution of claim 7, wherein said molten salt comprises cations selected from the group consisting of quarternary ammonium cations.

15. The electrolyte solution of claim 14, wherein said quarternary ammonium cations comprise pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, tetraalkylammonium cations, and N-methyl morpholinium cations.

16. The electrolyte solution of claim 15, wherein said quarternary ammonium cations have the formula (CH₃CH₂)₃N(R₂₄), wherein R₂₄ is alkyl having 2-10 carbons;

or having the formula (CH₃)₂(CH₃CHCH₃)N(R₂₅), wherein R₂₅ is alkyl having 2-10 carbons;

or having the structural formula

17. An electrochemical device comprising:

(a) a chamber for receiving an electrolyte solution;

(b) at least one anode in contact with said electrolyte solution in said chamber;

(c) at least one cathode in contact with said electrolyte solution in said chamber; and

(d) an electrolyte solution comprising comprising a molten salt solvent comprising at least one anion selected from the group consisting of bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide;

at least one reductant soluble in said molten salt solvent; and

at least one oxidant soluble in said molten salt solvent, said oxidant having the chemical formula [A][B]₂ wherein B is selected from the group consisting of bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide and wherein A is a dication having the structural formula

wherein R₁ and R₁′

are independently selected from alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

wherein R₂, R_2′

, R₃ and R_3′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₄ and R₄′

are independently selected from alkyl having 1-20 carbons;

wherein R₅, R_5′

, R₆, R_6′

, R₇, R_7′

, R₈, and R_8′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein n is 2-7;

wherein R₉ and R_9′

are independently selected from alkyl having 1-20 carbons;

wherein R₁₀, R_10′

, R₁₁, R_11′

, R₁₂, and R_12′

independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₁₃, R_13′

, R₁₄, R_14′

, R₁₅, R_15′

, R₁₆, and R_16′

are independently selected from hydrogen, alkyl having 1-20 carbons, aryl, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

or wherein A is a dication having the structural formula

wherein R₁₇ and R₁₈ are independently selected from alkyl having 1-20 carbons, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons;

wherein R₁₉, R₂₀, R₂₁, R₂₂, and R₂₃ are independently selected from alkyl having 1-20 carbons, alkyl-substituted aryl having 7-20 carbons, methoxy-substituted aryl having 7-20 carbons, nitro-substituted aryl having 6-20 carbons, cyano-substituted aryl having 7-20 carbons, trifluoromethyl-substituted aryl having 7-20 carbons.

18. The electrochromic device of claim 17, wherein A is a dication having the structural formula

19. The electrochromic device of claim 18, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁ and R_1′

are independently selected from alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20 carbons.

20. The electrochromic device of claim 19, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from the group consisting of alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20.

21. The electrochromic device of claim 20, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from methyl and benzyl.

22. The electrochromic device of claim 17, wherein said reductant is selected from the group consisting of N,N,N′

,N′

-tetramethyl-p-phenylenediamine, 2,5,10-trimethyl-3-phenyl-5,10-dihydrophenazine, 5-ethyl-10-methyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrobenzo(A)phenazine, 2,7-diphenoxy-5,10-dimethyl-5,10-dihydrophenazine, 2-phenoxy-5,10-dimethyl-5,10-dihydrophenazine, 2,7-bis(o-tolyl)-5,10-dimethyl-5,10-dihydrophenazine,2,3-dimethyl-7-trifluoromethyl-5,10-diethyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrophenazine, 2,3-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2,7-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2-vinyl-5,10-dimethyl-5,10-dihydrophenazine, 2-phenyl-5,10-dimethyl-5,10-dihydrophenazine, 5,10-diisopropyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrodibenzo(A,C)phenazine, 1,5,10-trimethyl-2-phenyl-5,10-dihydrophenazin, 2,3,5,10-tetramethyl-7-trifluoromethyl-5,10-dihydrophenazine, 2,3,5,10-tetramethyl-5,10-dihydrobenzo(B)phenazine, ferrocene, 1,1′

-dimethylferrocene, and decamethylferrocene.

23. The electrochromic device of claim 17, wherein said electrolyte solution does not include electrolyte solution does not include chloride anion, bromide anion, iodide anion, perchlorate anion, tetrafluoroborate anion, tetraphenylborate anion, carboxylate anion, carbonate anion, hexafluorophosphate anion, or hexafluoroantimonate anion.

24. The electrochromic device of claim 17, wherein said molten salt comprises cations selected from the group consisting of quarternary ammonium cations.

25. The electrochromic device of claim 24, wherein said quarternary ammonium cations comprise pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, tetraalkylammonium cations, or N-methyl morpholinium cations, or mixtures thereof.

26. The electrochromic device of claim 25, wherein said quarternary ammonium cations have the formula (CH₃CH₂)₃N(R₂₄), wherein R₂₄ is alkyl having 2-10 carbons;

or having the formula (CH₃)₂(CH₃CHCH₃)N(R₂₅), wherein R₂₅ is alkyl having 2-10 carbons;

or having the structural formula

27. An electrolyte solution prepared by dissolving at least one reductant and at least one electrochromic ionic compound into a molten salt, said molten salt comprising an anion selected from the group consisting of bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide, said electrochromic compound having the chemical formula

[A][B]₂

wherein B is selected from the group consisting of bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide and wherein A is a dication having the structural formula

28. The electrolyte solution of claim 27, wherein A is a dication having the structural formula

29. The electrolyte solution of claim 28, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁ and R_1′

are independently selected from alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20 carbons.

30. The electrolyte solution of claim 29, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from the group consisting of alkyl having 1-9 carbons, aryl, and alkyl-substituted aryl having 7-20.

31. The electrolyte solution of claim 30, wherein R₂═

R₂′

═

R₃═

R₃′

=hydrogen and wherein R₁═

R_1′

and are selected from methyl and benzyl.

32. The electrolyte solution of claim 27, wherein said molten salt comprises at least one quarternary ammonium cation.

33. The electrolyte solution of claim 32, wherein said quarternary ammonium cation comprises pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, tetraalkylammonium cations, and N-methyl morpholinium.

34. The electrolyte solution of claim 33, wherein said quarternary ammonium cations having the formula (CH₃CH₂)₃N(R₂₄), wherein R₂₄ is alkyl having 2-10 carbons;

or having the formula (CH₃)₂(CH₃CHCH₃)N(R₂₅), wherein R₂₅ is alkyl having 2-10 carbons;

or having the structural formula

35. The electrolyte solution of claim 27 wherein said electrolyte solution does not include chloride anion, bromide anion, iodide anion, perchlorate anion, tetrafluoroborate anion, tetraphenylborate anion, carboxylate anion, carbonate anion, hexafluorophosphate anion, or hexafluoroantimonate anion.

36. The electrolyte solution of claim 27, wherein said reductant is selected from the group consisting of N,N,N′

,N′

-tetramethyl-p-phenylenediamine, 2,5,10-trimethyl-3-phenyl-5,10-dihydrophenazine, 5-ethyl-10-methyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrobenzo(A)phenazine, 2,7-diphenoxy-5,10-dimethyl-5,10-dihydrophenazine, 2-phenoxy-5,10-dimethyl-5,10-dihydrophenazine, 2,7-bis(o-tolyl)-5,10-dimethyl-5,10-dihydrophenazine,2,3-dimethyl-7-trifluoromethyl-5,10-diethyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrophenazine, 2,3-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2,7-diphenyl-5,10-dimethyl-5,10-dihydrophenazine, 2-vinyl-5,10-dimethyl-5,10-dihydrophenazine, 2-phenyl-5,10-dimethyl-5,10-dihydrophenazine, 5,10-diisopropyl-5,10-dihydrophenazine, 5,10-dimethyl-5,10-dihydrodibenzo(A,C)phenazine, 1,5,10-trimethyl-2-phenyl-5,10-dihydrophenazin, 2,3,5,10-tetramethyl-7-trifluoromethyl-5,10-dihydrophenazine, 2,3,5,10-tetramethyl-5,10-dihydrobenzo(B)phenazine, ferrocene, 1,1′

-dimethylferrocene, and decamethylferrocene.