Bipyridinium salt solutions
First Claim
1. A solution which comprises a solvent;
- an anodic electrochromic compound which, upon oxidation of its zero-potential equilibrium state, undergoes an increase in molar extinction coefficient at at least one wavelength in the visible range; and
a cathodic electrochromic compound which is a salt of a cation of the formula ##STR11## wherein R7 and R8 are independently selected from the group consisting of an alkyl group with 1-20 carbon atoms and benzyl; and
R9, R10, R11, and R12 are independently selected from the group consisting of hydrogen and an alkyl group with 1-4 carbon atoms, provided that at least three of R9, R10, R11, and R12 are alkyl groups.
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Abstract
The present invention provides solutions of certain 4,4'"'"'-bipyridinium salts, such as salts of 1,1'"'"'- dibenzyl-2,2'"'"',6,6'"'"'-tetraalkyl-4,4'"'"'-bipyridinium cations. The solutions of the invention are employed as solutions of variable transmittance in solution-phase electrochromic devices, including such devices that are single-compartment and self-erasing. In the solutions of the invention in such devices, the bipyridinium salts are cathodic electrochromic compounds, as reduction of a cation of such a salt causes its molar extinction coefficient at at least one wavelength in the visible range to increase markedly. Electrochromic devices, in which solutions of the invention provide variable transmittance, are, in turn, components of variable transmittance in display devices, windows and other types of light filters, and variable reflectance mirrors, such as those that can be used as dimmable rearview mirrors in motor vehicles.
86 Citations
57 Claims
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1. A solution which comprises a solvent;
- an anodic electrochromic compound which, upon oxidation of its zero-potential equilibrium state, undergoes an increase in molar extinction coefficient at at least one wavelength in the visible range; and
a cathodic electrochromic compound which is a salt of a cation of the formula ##STR11## wherein R7 and R8 are independently selected from the group consisting of an alkyl group with 1-20 carbon atoms and benzyl; and
R9, R10, R11, and R12 are independently selected from the group consisting of hydrogen and an alkyl group with 1-4 carbon atoms, provided that at least three of R9, R10, R11, and R12 are alkyl groups. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
- an anodic electrochromic compound which, upon oxidation of its zero-potential equilibrium state, undergoes an increase in molar extinction coefficient at at least one wavelength in the visible range; and
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36. A solution which is liquid at room temperature and comprises a solvent and a BF4-, PF6-, or ClO4- salt of a cation of Formula XVII ##STR12## wherein R36 and R37 independently selected from the group consisting of benzyl and alkyl of 1-20 carbon atoms;
- and R34, R35, R38 and R39 are independently selected from the group consisting of hydrogen and alkyl groups of 1-4 carbon atoms, provided that at least three of R34, R35, R38 and R39 are alkyl.
- View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
Specification