Benzpyrylium dyes, and processes for their preparation and use
US5262549A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1993 |
| Grant date | Nov 16, 1993 |
| Priority date | — |
| Expiry date | Mar 29, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B23/08
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
4-[3-(benz[b]pyran-4-ylidene)prop-1-enyl]benz[b]pyrylium, 4-[5-(4H-benz[b]pyran-4-ylidene)penta-1,3-dienyl]benz[b]pyrylium and 4-[7-(4H-benz[b]pyran-4-ylidene)hepta-1,3,5-trienyl]benz[b]pyrylium dyes, wherein at least one of the benzpyrylium nuclei carries at its 2-position a substituent in which a non-aromatic carbon atom is bonded directly to the benzpyrylium nucleus, subject to the proviso that if the or each 2-substituent contains an aromatic nucleus, this aromatic nucleus is not conjugated with the benzpyrylium nucleus, are useful as visible and near infra-red absorbers, having high extinction coefficients and a reduced tendency to develop absorptions at shorter wavelengths when dispersed in polymeric media.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.