BODIPY
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BODIPY, short for boron-dipyrromethene, is a class of fluorescent dyes. It is comprised of dipyrromethene complexed with a disubstituted boron atom, typically a BF2 unit. The IUPAC name for the BODIPY core is 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene. This compound, representing the unsubstituted BODIPY, has never been prepared.
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[edit] Introduction
BODIPY dyes are notable for their uniquely small Stokes shift, high, environment-independent quantum yields, often approaching 100% even in water, and sharp excitation and emission peaks contributing to overall brightness. The combination of these qualities makes BODIPY fluorophore an important tool in a variety of imaging applications.
[edit] Synthesis
BODIPY are prepared by reacting a dipyrromethene precursor with boron trifluoride etherate in the presence of a tertiary amine. Dipyrromethenes are accessed from a suitable pyrrole, by several methods. Normally, one alpha-position in employed pyrroles is substituted and the other is free. Condensation of such pyrrole, often available from Knorr pyrrole synthesis, with an aromatic aldehyde in the presence of TFA gives dipyrromethane, which is oxidized to dipyrromethene using a quinone oxidant such as DDQ or p-chloranil. Alternatively, dipyrromethenes are prepared directly by reacting a pyrrole with an activated carboxylic acid derivative, usually acid chloride. Intermediate dipyrromethanes may be isolated and purified, but isolation of dipyrromethenes is usually compromised by their instability. Unsymmetrical dipyrromethenes can be obtained by condensing pyrroles with 2-acylpyrroles.
[edit] Spectral properties
[edit] References
- BODIPY Dyes and Their Derivatives: Syntheses and Spectroscopic Properties. Loudet, A.; Burgess, K. Chem. Rev. 2007, 107(11), 4891-4932. DOI: 10.1021/cr078381n
