Electrochromic composition

Abstract

The present invention relates to an electrochromic composition comprising at least one reducing compound, at least one oxidizing compound which is selected from specific viologen derivatives, and at least one dye. Said composition can be used as a variable transmittance medium for the manufacture of an optical article, such as an ophthalmic lens.

Claims

1. An electrochromic composition comprising: at least one reducing compound; at least one dye; at least one electrochromic oxidizing compound selected from viologen derivatives of formula (I) ##STR00096## at least one least one electrochromic oxidizing compound selected from viologen derivatives of formula (II) ##STR00097## wherein R.sup.1 and R.sup.2 are each independently selected from optionally substituted phenyl groups; R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each independently selected from H, alkyl, alkoxy, alkylthio, haloalkyl, haloalkoxy, haloalkythio, polyakylenoxy, alkoxycarbonyl, aryl, substituted aryl, heteroaryl and substituted heteroaryl, wherein the alkyl group may be substituted by one or more substituents independently selected from alkoxy, cycloalkyl, aryl, substituted aryl, heteroaryl and substituted heteroaryl; n, p, q and r are each independently an integer from 0 to 4, wherein when n, p, q or r are two or more, each of the R.sup.3, each of the R.sup.4, each of the R.sup.5 or each of the R.sup.6 may be identical or different; A and B are respectively selected from nitrogen and —N.sup.+(R.sup.7a)—, and from nitrogen and —N.sup.+(R.sup.7b)—, wherein R.sup.7a and R.sup.7b are independently selected from: alkyl which may be substituted by one or more groups independently selected from halogen, alkoxy, cycloalkyl, vinyl, allyl, aryl, substituted aryl, heteroaryl and substituted heteroaryl; aryl and heteroaryl which may be both substituted by one or more groups independently selected from: halogen, cyano, nitro, alkyl, haloalkyl, arylalkyl, cycloalkyl, cycloalkylalkyl and heterocycloalkylalkyl, alkenyl, alkynyl, allyl, vinyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, —N(aryl).sub.2, —N(aryl)CO(aryl), —CO-aryl and —CO-substituted aryl; —OR.sup.8, —SR.sup.8, —S(O)R.sup.8, —S(O.sub.2)R.sup.8, —S(O.sub.2)NR.sup.8R.sup.9, —NR.sup.8R.sup.9, —NR.sup.8COR.sup.9, —NR.sup.8CO(aryl), —NR.sup.8aryl, —CH.sub.2OR.sup.8, —CH.sub.2SR.sup.8, —CH.sub.2R.sup.8, —CO—R.sup.8 and —CO.sub.2R.sup.8 wherein R.sup.8 and R.sup.9 are independently selected from H, alkyl, haloalkyl, arylalkyl, cycloalkyl, cycloalkylalkyl and heterocycloalkylalkyl; —S(O.sub.2)NR.sup.10R.sup.11 and —NR.sup.10R.sup.11, wherein R.sup.10 and R.sup.11 form together with the nitrogen atom to which they are linked a saturated 5 to 7 membered heterocycloalkyl which may comprise in addition to the nitrogen atom one further heteroatom selected from oxygen, nitrogen and sulphur, and which may be optionally substituted by one or two groups independently selected from halogen, —R.sup.8, —OR.sup.8, and —NR.sup.8R.sup.9, wherein R.sup.8 and R.sup.9 are as defined above; —V—W—R.sup.12 wherein: V is selected from oxygen, —N(R.sup.8)—, sulphur, —S(O)— and —S(O.sub.2)— wherein R.sup.8 is as defined above; W is alkylene, which may be substituted by one or more groups independently selected from halogen and alkoxy; and R.sup.12 is selected from —OR.sup.8, —NR.sup.8(alkyl) and —SR.sup.8 wherein R.sup.8 is as defined above; and —OC(O)—R.sup.13 wherein R.sup.13 is selected from alkyl, haloalkyl, alkenyl, —W—R.sup.12, and aryl group which may be substituted by 1 to 4 groups selected from halogen, —R.sup.8, —OR.sup.8, —SR.sup.8, —NR.sup.8R.sup.9, —NR.sup.10R.sup.11, —CO—R.sup.8, —C(O)OR.sup.8, wherein R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12 and W are as defined above; Z is selected from: alkylene; cycloalkylene; and a bivalent groups of formula —R.sup.14—Y—R.sup.15—, wherein R.sup.14 and R.sup.15 are each independently selected from single bond, alkylene and cycloalkylene; and Y is selected from arylene, cycloalkylene, heteroarylene, arylene-arylene or arylene-CR′R″-arylene wherein R′ and R″ form together with the carbon to which they are linked a carbocyclic group; wherein said alkylene, cycloalkylene, arylene, heteroarylene and carbocyclic groups may be substituted by one or more substituents selected from halogen, alkyl, alkoxy, alkylthio, hydroxyalkyl, acyloxy, cycloalkyl, aryl, substituted aryl, aryloxy heteroaryl and substituted heteroaryl; m is 2 if A and B are nitrogen, 3 if one of A and B is nitrogen and the other is not nitrogen, and 4 if both A and B are not nitrogen; and X″ is a counterion.

2. The electrochromic composition according to claim 1, wherein Z is selected from C.sub.1-C.sub.12 alkylene, aryl substituted C.sub.1-C.sub.12 alkylene, phenylene, naphthylene, (C.sub.1-C.sub.4 alkylene)-phenylene-(C.sub.1-C.sub.4 alkylene), (C.sub.1-C.sub.4 alkylene)-naphthylene-(C.sub.1-C.sub.4 alkylene), quinoxaline-2,3-diyl, (C.sub.1-C.sub.4 alkylene)-quinoxaline-2,3-diyl-(C.sub.1-C.sub.4 alkylene), phenylene-phenylene, (C.sub.1-C.sub.4 alkylene)-phenylene-phenylene-(C.sub.1-C.sub.4 alkylene) and phenylene-fluorenylene-phenylene, preferably Z is selected from —CH.sub.2—, —(CH.sub.2).sub.2—, —(CH.sub.2).sub.3—, —(CH.sub.2).sub.4—, —(CH.sub.2).sub.5—, —CH.sub.2—CH(CH.sub.3)—CH.sub.2—, —CH.sub.2—CH(CH.sub.2Phenyl)-CH.sub.2—, —(CH.sub.2).sub.2—CH(CH.sub.3)—CH.sub.2—, —(CH.sub.2).sub.3—CH(CH.sub.3)—CH.sub.2—, —(CH.sub.2).sub.2—CH(CH.sub.3)—(CH.sub.2).sub.2—, ##STR00098## ##STR00099##

3. The electrochromic composition according to claim 1, wherein R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each independently selected from C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxycarbonyl, alkanoyl, aroyl, aryl and heteroaryl, wherein the aryl and heteroaryl may be substituted by one or more substituents selected from C.sub.1-C.sub.4 alkyl and C.sub.1-C.sub.4 haloalkyl, preferably, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each independently selected from methyl, ethoxycarbonyl, phenyl, p-methylphenyl and p-trifluoromethylphenyl.

4. The electrochromic composition according to claim 1, wherein the counterion X.sup.− is selected from halide, tetrafluoroborate, tetraphenylborate, hexafluorophosphate, nitrate, methanesulfonate, trifluoromethane sulfonate, toluene sulfonate, hexachloroantimonate, bis(trifluoromethanesulfonyl)imide, perchlorate, acetate and sulfate.

5. The electrochromic composition according to claim 1, wherein at least one of the viologen derivatives is selected from compounds of formula (III): ##STR00100## wherein Z, and X.sup.− are as defined in formula (II), and R.sup.16 and R.sup.17 are selected from alkyl and optionally substituted phenyl groups.

6. The electrochromic composition according to claim 1, wherein at least one of the viologen derivatives is selected from compounds of formula (IV): ##STR00101## wherein R.sup.4, R.sup.5, Z, A, B, m and X.sup.− are as defined in formula (II) and at least one of R.sup.4 and R.sup.5 is not H.

7. The electrochromic composition according to claim 1, wherein said viologen derivatives are selected from compounds I-1 to 1-50, III-1 to 111-18 and IV-1 and IV-14: TABLE-US-00002 Compound Formula I-1 I-2 I-3 I-4 I-5 I-6 I-7 I-8 I-9 I-10 I-11 I-12 I-13 I-14 I-15 I-16 I-17 I-18 I-19 I-20 I-21 I-22 I-23 I-24 I-25 I-26 I-27 I-28 I-29 I-30 I-31 I-32 I-33 I-34 I-35 I-36 I-37 I-38 I-39 I-40 I-41 I-42 I-43 I-44 I-45 I-46 I-47 I-48 I-49 I-50 III-1 III-2 III-3 III-4 III-5 III-6 III-7 III-8 III-9 III-10 III-11 III-12 III-13 III-14 III-15 III-16 III-17 III-18 III-19 IV-1 IV-2 IV-3 IV-4 IV-5 IV-6 IV-7 IV-8 IV-9 IV-10 IV-11 IV-12 IV-13 IV-14 wherein Me represents methyl, Ph represents phenyl and Tol represents 4-methylphenyl.

8. The electrochromic composition according to claim 1, wherein the reducing compound is selected from ferrocene and their derivatives such as ethyl ferrocene, t-butyl ferrocene; phenoxazine and their derivatives, such as N-benzylphenoxazine; phenazine and their derivatives, such as 5,10-dihydrophenazine, N,N,N′,N′-tetramethyl-p-phenylenediamine; phenothiazine and their derivatives, such as 10-methylphenothiazine and isopropylphenothiazine; thioanthrene; and tetrathiafulvalene.

9. The electrochromic composition according to claim 8, wherein said composition comprises a fluid, mesomorphous or gel host medium preferably selected from the group consisting of organic solvents, liquid crystals, polymers, liquid crystal polymers and mixtures thereof.

10. The electrochromic composition according to claim 1, wherein the dye is selected from the group consisting of: organic or inorganic photochromic and/or dichroic substances; electrochromic substances distinct from the first constituent of this invention and which may be selected among the above compounds of Formulas (I) and/or (II) or among different electrochromic compounds; organic and inorganic pigments, especially in the form of nanoparticles; organic dyes; optical brighteners; or mixtures thereof.

11. An electrochromic device comprising the composition as defined in claim 1.

12. The electrochromic device according to claim 11, wherein said electrochromic device comprises a mechanism for holding the composition in a mechanically stable environment.

13. The electrochromic device according to claim 11, wherein said electrochromic device comprises at least one transparent electrochromic cell comprising a pair of opposed substrates facing each other and forming a gap, and the gap is filled with the electrochromic composition as defined in claim 1.

14. The electrochromic device according to claim 11, wherein said electrochromic device is an optical article.

15. The electrochromic device according to claim 14, wherein the optical article is an optical lens or optical filter, window, visor, mirror or displays.

16. The electrochromic device according to claim 15, wherein the optical article is an optical lens.

17. The electrochromic device according to claim 15, wherein the optical article is an ophthalmic lens.

Description

EXAMPLES

(1) This invention will be further illustrated by the following non-limiting examples which are given for illustrative purposes only and should not restrict the scope of the appended claims.

Example 1: Composition Comprising Electrochromic Compounds and a Photochromic Substance

(2) A composition was prepared by dissolving, in propylene carbonate (82.3 wt. %): the electrochromic compound corresponding to Formula I-10 above (3.5 wt. %), the electrochromic compound corresponding to Formula III-10 above (2.0 wt. %), 10-methylphenothiazine (5.9 wt. %) as a reducing agent, a photochromic substance of the naphtopyrane type, produced by VIVIMED LABS under the trade name Reversacol® Berry Red (0.8 wt. %), and tetrabutylammonium tetrafluoroborate, hereafter designated as TBA BF.sub.4.sup.− (5.5 wt. %).

(3) A tank was filled at room temperature and atmospheric pressure with the electrochromic composition as described above. A cell was then placed vertically in the tank under atmospheric pressure in such way that the opening was located above the solution level. This cell included two mineral glass substrates facing each other, the internal sides of which were coated with transparent conductive electrodes made of indium tin oxide (ITO). The substrates were held at fixed distance from one another by using spacers of 75 μm, in order to form a gap. The edge of the cell was sealed with a UV curable adhesive in such a way that an opening of 5 mm was left.

(4) The tank with the cell was placed in a vacuum-desiccator, which was evacuated to 0.5 mBar. During the aeration of the tank under the introduction of an inert gas, the electrochromic formulation filled the entire volume of the gap through the opening. The opening was then sealed with a UV curable adhesive in order to make the cell hermetic. The electrical connection was made by two silver plated copper wires, sealed on each ITO glass substrate with a silver charged epoxy adhesive.

(5) A potential of 0.9V was applied between the electrodes and the color obtained was assessed visually. It was observed that the composition was slightly pink in the inactive state and that this colour was only due to the photochromic substance included therein. After activation, the sample had a nice grey-purple colour which changed reversibly when reversing the polarity.

(6) The transmission level (Tv) of the composition was also measured according to the ISO Standard 8980-3, in the 380 nm-800 nm wavelength range, using a spectrophotometer. It corresponds to the transmission factor as defined in the ISO Standard 13666:1998. It was observed that Tv decreased from 75% to 16% when applying the electrical potential.

(7) It was further noticed that the coloration/discoloration kinetics did not seem to be affected by the presence of the photochromic substance.

(8) The photochromic substance also kept its photochromic properties, which was checked by activating the sample with a UV lamp (v1208b1 of 2×8 W, 365 nm, 1400 μW/cm.sup.2). The photochromic substance coloured in red when activated by the UV light.

(9) This example demonstrates that it is possible to obtain both a photochromic effect and an electrochromic effect using the above composition. The sample which was both UV- and electrically activated had a dark purple colour.

Example 2: Composition Comprising an Electrochromic Compound and an Organic Dye

(10) A composition was prepared by dissolving, in propylene carbonate (88.8 wt. %): the electrochromic compound corresponding to Formula I-10 above (4.3 wt. %), ferrocene (1.2 wt. %) as a reducing agent, an organic dye, which was an azo metal complex dye supplied by CLARIANT under the trade name Savinyl® Red 2 BLSE (1.4 wt. %), and tetrabutylammonium tetrafluoroborate, hereafter designated as TBA BF.sub.4.sup.− (4.3 wt. %).

(11) This composition has a red colour in the inactive state, which was due to the presence of the organic dye. Its colour turned to brown when voltage of 0.9V was applied to the electrochromic device.

Example 3: Composition Comprising an Electrochromic Compound and a Dichroic Compound

(12) A composition was prepared by dissolving, in propylene carbonate (92.35 wt. %): the electrochromic compound corresponding to Formula I-10 above (1.48 wt. %), Methylphenothiazine (1.21 wt. %) as a reducing agent, a mixture of three dichroic dyes, which were anthraquinone derivatives supplied by NEMATEL under the trade name Blue AB4® (0.95 wt. %), Red® AR1 (0.84 wt. %), and Yellow® AG1 (0.86 wt. %), and tetrabutylammonium tetrafluoroborate, hereafter designated as TBA BF.sub.4.sup.− (2.31 wt. %).

(13) This composition has a dark blue colour in the inactive state, which was due to the presence of the dichroic dyes. As the dichroic dyes were not oriented in the same direction, the residual colour corresponded to the absorption obtained with an average orientation of the molecules.

(14) Its colour turned to dark green when a voltage of 0.9V was applied to the electrochromic device.

(15) It has also been checked that the colour of the dichroic compound was not modified with the application of the voltage.

Example 4: Composition Comprising Electrochromic Compounds and Liquid Crystals

(16) A composition was prepared by dissolving, in propylene carbonate (40.0 wt. %): the electrochromic compound corresponding to Formula I-10 above (2.0 wt. %), the electrochromic compound corresponding to Formula III-10 above (0.9 wt. %), 10-methylphenothiazine (1.4 wt. %) as a reducing agent, liquid crystals sold by MERCK under the trade name E7 (53.8 wt. %), and tetrabutylammonium tetrafluoroborate, hereafter designated as TBA BF.sub.4.sup.− (1.9 wt. %).

(17) The transmission rate of the composition, which was initially clear (uncoloured), decreased from 82% when in the inactive state to 30% when electrically activated (with a voltage of 0.9V) and its colour simultaneously turned to a grey-green colour.

(18) This example shows that the presence of liquid crystals in a composition of this invention, even in high amounts, does not affect the electrochromic properties of the composition. It is thus possible to incorporate dichroic compounds and to orientate them, as said dichroic compounds need to be formulated into liquid crystals.

Example 5: Composition Comprising Two Electrochromic Compounds

(19) A composition was prepared by dissolving, in propylene carbonate (82.1 wt. %): the electrochromic compound corresponding to Formula I-18 above (3.7 wt. %), the electrochromic compound corresponding to Formula III-4 above (1.0 wt. %), phenoxazine (1.9 wt. %) as a reducing agent, PMMA (7.8 wt. %), and tetrabutylammonium tetrafluoroborate, hereafter designated as TBA BF.sub.4.sup.− (3.5 wt. %), wherein one of the electrochromic compounds was used as a dye according to this invention.

(20) At the inactive state, the composition had a yellow colour which turned to brown when a voltage of 1.1V was applied. When the polarity was reversed, the colour turned back to pale brown but did not return to yellow. The colour of the composition thus changed from brown to light brown and vice versa over several cycles.

Example 6: Composition Comprising Two Electrochromic Compounds

(21) A composition was prepared by dissolving, in propylene carbonate (92 wt. %): the electrochromic compound corresponding to Formula I-25 above (2.4 wt. %), the electrochromic compound corresponding to Formula III-3 above (0.9 wt. %), phenoxazine (1.1 wt. %) as a reducing agent, and tetrabutylammonium tetrafluoroborate, hereafter designated as TBA BF.sub.4.sup.− (3.6 wt. %), wherein one of the electrochromic compounds is used as a dye according to this invention.

(22) During successive activation cycles (with application of a voltage of 1V), the colour of the composition varied from pale green to dark green and vice versa.