Electrochromic system

• US 6,277,307 B1
• Filed: 08/03/1998
• Issued: 08/21/2001
• Est. Priority Date: 02/15/1996
• Status: Expired due to Fees

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Claussen, Uwe, Berneth, Horst
• Primary Examiner(s): TUCKER, PHILIP C
• Application Number:
  US09/117,449
• Time in Patent Office: 1,114 Days
• Field of Search: 252/583, 359/265, 359/267, 359/272, 359/275
• US Class Current: 252/583
• 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: G02F 2001/1502 complementary cell
• CPC Class Codes: G02F 2001/15145 the electrochromic layer comprises a mixture of anodic and cathodic compounds

Abstract

In the novel electrochromic system comprising at least one oxidizable substance RED₁ and at least one reducible substance OX₂, each of which, accompanied by an increase in the absorbance in the visible region of the spectrum, is converted from a weakly colored or colorless form into a colored form wherein the reciprocal conversion of oxidized and reducible form takes place by a σ bond being broken or formed, respectively.

Claims

1. An electrochromic system comprising at least one oxidizable substance RED₁ which, by releasing electrons at an anode, is converted from a weakly colored or colorless form in to a colored form OX₁, and at least one reducible substance OX₂ which, by accepting electrons at a cathode, is converted from a weakly colored or colorless form into a colored form RED₂, the absorbence in the visible region of the spectrum increasing in each of these cases, and the weakly colored or colorless form being recovered in each case after charge equalization, wherein the reciprocal conversion of oxidized and reducible form takes place by a σ

bond being broken or formed, respectively, for OX₂, wherein the reducible substance OX₂ comprises a cyclic organic compound which after accepting 1 or 2 electrons, is converted, one of the σ

bond of the ring being broken, into an open-ring compound and which, by releasing 1 or 2 electrons, is converted once more into the cyclic starting compound, in each case precisely two electrons being transferred overall.

2. The electrochromic system as claimed in claim 1, which comprises, as the reducible substance OX₂ which is converted reversibly, a σ

bond being broken, into the corresponding substance RED₂, a compound selected from the group consisting of the tetrazolium salts, benzotriazolium salts, naphthotriazolium salts, cyclopropanes and [1.1.0]bicyclobutanes.

3. The electrochromic system as claimed in claim 1, which comprises, as the reducible substance OX₂, at least one compound of the formulae

in which

R¹ to R⁵, independently of one another, represent C₆- to C₁₀-aryl or an aromatic or quasi-aromatic five- or six-membered heterocyclic ring, each of which is optionally benzanellated,

R⁷, R⁹, R¹³ and R¹⁴, independently of one another, represent a radical of the formulae (V) to (VII)

R⁸, R¹⁵ and R¹⁶, independently of one another, represent C₆- to C₁₀-airyl, C₇-C₁₁-aroyl or a radical of the formulae (V) to (VII),

R¹⁰ to R¹², R¹⁷ and R¹⁸, independently of one another, represent hydrogen, C₁- to C₄-alkyl, halogen or cyano,

E¹ and E², independently of one another, represent O, S or N—

R¹⁹,

R¹⁹ and R²², independently of one another, represent C₁- to C₁₈-alkyl, C₂- to C₈-alkenyl, C₄- to C₇-cycloalkyl, C₇- to C₁₅-aralkyl or C₆- to C₁₀-aryl,

R⁶, R²⁰, R²¹, R²³ and R²⁴, independently of one another, represent hydrogen, C₁- to C₄-alkyl, C₁- to C₄-alkoxy, halogen, cyano, nitro or C₁- to C₄-alkoxycarbonyl, or

R²⁰ and R²¹, or R²³ and R²⁴, jointly form a —

CH═

CH—

CH═

CH—

bridge, and

X⁻

represents a colorless anion which is redox-inert under the conditions.

4. The electrochromic system as claimed in claim 1, which comprises, as the oxidizable substance RED₁, an organic compound which is able to release 2 electrons reversibly in two stages, the difference of the two oxidation states being preferably at least 250 mV.

5. The electrochromic system as claimed in claim 4, which comprises, as the substance RED₁ which is reversibly oxidizable in two stages, a compound of the formulae (VIIII) to (XVII)

in which

R²⁵ to R²⁸, R³¹, R³², R³⁵, R³⁶, R⁴³, R⁵⁰ and R⁵¹, independently of one another, represent C₁- to C₁₈-alkyl, C₂- to C₁₂-alkenyl, C₄- to C₇-cycloalkyl, C₇- to C₁₅-aralkyl or C₆- to C₁₀-aryl, and R⁴³, R⁵⁰ and R⁵¹ additionally represent hydrogen,

R²⁹, R²⁰, R³³, R³⁴, R³⁷, R³⁸, R³⁹, to R⁴², R⁴⁴, R⁴⁵, R⁴⁶ to R⁴⁹ and R⁵² to R⁵⁵, independently of one another, represent hydrogen, C₁- to C₄-alkyl, C₁- to C₄-alkoxy, halogen, cyano, nitro, C₁- to C₄-alkoxycaronyl or C₆- to C₁₀-aryl, and R⁵⁴ and R⁵⁵ additionally represent an aromatic or quasi-aromatic five-or six-membered heterocyclic ring, each of which is optionally benzanellated, or a radical of the formulae (V) or (VI), and R⁴⁵ additionally represents NR⁷³R⁷⁴, or

R⁴⁶ and R⁴⁷ and/or R⁴⁸ and R⁴⁹ form a —

(CH₂)₃—

, —

(CH₂)₄—

, —

(CH₂)₅—

or —

CH═

CH—

CH═

CH-bridge,

Z¹ represents a direct bond, a —

CH═

CH—

or —

N═

N—

bridge,

═

Z²═

represents a direct double bond, a ═

CH═

CH═

or ═

N—

N═

bridge,

E³ to E⁵, E¹⁰ and E¹¹, independently of one another, represent O, S, NR⁵⁶ or C(CH₃)₂, and E⁵ additionally represents C═

O or SO₂, or

E³ and E⁴, independently of one another, additionally represent —

CH═

CH—

,

E⁶ to E⁹, independently of one another, represent S, Se or NR⁵⁶,

R⁵⁶, R⁷³ and R⁷⁴, independently of one another, represent C₁- to C₁₂-alkyl, C₂- to C₈-alkenyl, C₄- to C₇-cycloalkyl, C₇- to C₁₅-aralkyl or C₆- to C₁₀-aryl, and R⁷³ additionally represents hydrogen, or

R⁷³ and R⁷⁴, in the context of NR⁷³R⁷⁴, jointly with the N atom to which they are bound form a five- or six-membered saturated ring which may contain further heteroatoms,

R⁶⁵ to R⁷², independently of one another, represent hydrogen, C₁- to C₆-ai-kyl, C₁- to C₄- alkoxy, cyano, C₁- to C₄-alkoxycarbonyl or C₆- to C₁₀-aryl, and

R⁶⁵ and R⁶⁶, and R⁷¹ and R⁷² independently of one another, may additionally form a —

(CH₂)₃—

, —

(CH₂)₃—

, —

(CH₂)₄—

or —

CH═

CH—

CH═

CH—

bridge, and

u represents an integer between 0 and 10.

6. The electrochromic system as claimed in claim 1, which comprises at least one couple of oxidizable and reducible substances RED₁/OX₂.

7. The electrochromic system as claimed in claim 1, which comprises a couple RED₁/OX₂, the substance OX₂ being a tetrazolinium salt of formula (I) as claimed in claim 3

in which

R¹ and R² correspond to a radical of formula (XIX),

and

R³ corresponds to a radical of formula (XX),

 

in which

R⁵⁷, R⁵⁹ and R⁶⁰, independently of one another, represent hydrogen, methyl, ethyl, methoxy, ethoxy, cyano, nitro, —

N⁺CH₃)₃ or COOH, or

R⁵⁷ and R⁵⁹ jointly form an —

O—

CH₂—

O—

bridge,

R⁵⁸ represents hydrogen, methyl, methoxy or chlorine,

R⁶¹ represents methyl, difluoromethyl, trifluoromethyl, methoxycarbonyl, ethoxycarbonyl or phenyl,

R⁶² represents hydrogen, methyl, ethyl, phenyl or chlorine, or

R⁶¹ and R⁶² together form a —

CH═

CH—

CH═

CH—

or —

CH═

CH—

C(OCH₃)═

CH—

bridge,

E¹² represents S,

X⁻

represents a colorless anion which is redox-inert under the conditions, and the substance RED, being a compound selected from the group consisting of the formulae (VIII), (X), (XI), (XIV) and (XV) as claimed in claim 6, in which

R²⁵ to R²⁸, R³¹, R³², R³⁵, R³⁶, R⁴³ and R⁵⁶ represent methyl, ethyl, propyl, butyl, pentyl, hexyl or benzyl, R²⁵ to R²⁸, R³¹ and R³², and R³⁵ and R³⁶, respectively, being identical and R⁴³ additionally representing hydrogen,

R¹⁹ and R⁴⁴ represent hydrogen, R⁴⁵ represents hydrogen, methoxy, ethoxy, dimethylamino, diethylamino, anilirio, N-methylanilino or piperidino,

R³³ and R³⁴ are identical and represent hydrogen, methyl, methoxy, chlorine, cyano or methoxycarbonyl,

E³ to E⁵ represent O, S or NR⁵⁶, but E³ and E⁴ are identical,

R³⁷ and R³⁸ are identical and represent hydrogen, methyl, ethyl, propyl, butyl or phenyl,

Z¹ represents a direct bond or —

CH═

CH—

,

R⁴⁶ to R⁴⁹ are identical and represent hydrogen, methyl, methoxy, chlorine, cyano, methoxycarbonyl, ethoxycarbonyl or phenyl,

E⁶ to E⁹ are identical and represent S, Se or NR⁵⁶,

═

Z²═

represents a direct double bond, a ═

CH—

CH═

or ═

N—

N═

bridge,

R⁶⁵ and R⁶⁶, and R⁷¹ and R⁷² represent a —

(CH₂)₃—

or —

(CH₂)₄—

bridge,

R⁶⁷ to R⁷⁰ represent hydrogen, and

u represents an integer from 1 to 6.

8. The electrochromic system as claimed in claim 1, which comprises a couple of oxidizable and reducible substances RED₁/OX₂, RED₁ and OX₂ being linked via a bridge B and OX₂ corresponding to a compound of the formulae (I) to (IV) as claimed in claim 3 and RED₁ corresponding to one of the formulae (VIII) to (XVIII) as claimed in claim 5, in which

B represents a bridge of the formulae —

(CH₂)_n—

or —

[Y¹_s—

(CH₂)_m—

Y²]_o—

(CH₂)_p—

Y³_q—

which may be substituted by C₁- to C₄-alkyl, C₁- to C₄-alkoxy, halogen or phenyl,

Y¹ to Y³, independently of one another, represent O, S, NR⁶³, COO, CONH, NHCONH, cyclopentanediyl;

cyclohexanediyl, phenylene or naphthylene,

R⁶³ represents C₁- to C₆-alkyl, C₂- to C₆-alkenyl, C₄- to C₇-cycloalkyl, C₇- to C₁₅-aralkyl or C₆- to C₁₀-aryl,

n represents an integer from 1 to 12,

m and p, independently of one another, represent an integer from 0 to 8,

o represents an integer from 0 to 6,

q and s, independently of one another, represent 0 or 1,

R¹⁹, R²¹ to R²⁵, R³¹, R³⁵, R³⁹, R⁴¹, R⁴³, R⁴⁶, R⁵⁰, R⁵⁴, R⁵⁶, R⁵⁷, R⁵⁹, R⁶¹, R⁶², R⁶⁴, R⁶⁵ or R⁶⁶ form a direct bond to the bridge B, or R⁴⁶, R⁵⁷ or R⁵⁹ form a —

COO—

bridge to the bridge B.

9. An electrochromic fluid comprising an electrochromic system as claimed claim 1 and at least one inert solvent.

10. An electrochromic device containing an electrochromic fluid as claimed in claim 9.

11. The electrochomic device as claimed in claim 10, which is designed as a cell, as a window pane, mirror, canopy or display.

12. The electrochromic device as claimed in claim 10, which comprises two transparent glass or plastic panes which face one another, one of which optionally being mirrored and whose sides which face one another are coated electroconductively, between which the electrochromic fluid is contained.

13. The electrochromic device as claimed in claim 11, which comprises two transparent glass or plastic panes which face one another, one of which optionally being mirrored and whose sides which face one another are coated electroconductively, between which the elecrochromic fluid is contained.

14. The electrochomic device as claimed in claim 11, which is designed as a cell and the cell is a solar cell.