Use of oxazine compounds for making chromogenic materials
US8304537B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 2008 |
| Grant date | Nov 6, 2012 |
| Priority date | — |
| Expiry date | May 9, 2029 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K2211/1033
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Heterocyclic compounds incorporating a [1,3]oxazine ring may be used to make chromogenic materials. These molecules switch from a colorless state to a colored form upon addition of either acid or base. In both instances, the [1,3]oxazine ring opens in response to the pH change forming an indolium cation, after the addition of acid, or a phenolate anion, after the addition of base. Alternatively, the switch may occur in response to a change in electrical current or potential or a change in temperature. Chromophores absorb in the visible region of the electromagnetic spectrum. Hence, their formation translates into the appearance of color. These processes are fully reversible and the original colorless state can be regenerated by switching the pH back to neutral. Thus, these halochromic compounds can be used to develop displays, filters, indicators, lenses, sensors, switches, or windows able to switch their color in response to pH changes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.