Squaraine dye
From Wikipedia, the free encyclopedia
Squaraine Dyes are a class of organic dyes with very intense fluorescence spectra in the near infrared region. (excitation are typically around 620nm and fluorescence are typically upward of 660-670nm for aniline derivatives). They are typically encumbered by nucleophilic attack of the central squaric acid derivative which is highly electron deficient. This encumbrance can be attenuated by the formation of a rotaxane around the dye to protect it from nucleophiles. They are currently used as sensors for ions and have recently, with the advent of protected squanaine derivatives, been exploited in biomedical imaging.
They are synthetically derived from squaric acid which undergoes an electrophilic aromatic substitution reaction with an aniline or another electron rich aromatic derivative to form a highly conjugated product with extensive charge distribution.
[edit] References
[edit] External links
- Bradley Smith Research Group. Developing Squaraine based rotaxane dyes which are extremely stable to aqueous environments.. Retrieved on November 4, 2005.
