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Title: Carbazole-Linked Near-Infrared Aza-BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep-Tissue Imaging
Authors: Gawale, Yogesh
Adarsh, Nagappanpillai
Kalva, Sandeep Kumar
Joseph, Joshy
Pramanik, Manojit
Ramaiah, Danaboyina
Sekar, Nagaiyan
Keywords: Dyes/pigments
Issue Date: 2017
Source: Gawale, Y., Adarsh, N., Kalva, S. K., Joseph, J., Pramanik, M., Ramaiah, D., et al. (2017). Carbazole-Linked Near-Infrared Aza-BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep-Tissue Imaging. Chemistry - A European Journal, 23(27), 6570-6578.
Series/Report no.: Chemistry - A European Journal
Abstract: Four new N-ethylcarbazole-linked aza-boron-dipyrromethene (aza-BODIPY) dyes (8 a,b and 9 a,b) were synthesized and characterized. The presence of the N-ethylcarbazole moiety shifts their absorption and fluorescence spectra to the near-infrared region, λ≈650–730 nm, of the electromagnetic spectrum. These dyes possess strong molar absorptivity in the range of 3–4×104 m−1 cm−1 with low fluorescence quantum yields. The triplet excited state and singlet oxygen generation of these dyes were enhanced upon iodination at the core position. The core-iodinated dyes 9 a,b showed excellent triplet quantum yields of about 90 and 75 %, with singlet oxygen generation efficiency of about 70 and 60 % relative to that of the parent dyes. Derivatives 8 a,b showed dual absorption profiles, in contrast to dyes 9 a,b, which had the characteristic absorption band of aza-BODIPY dyes. DFT calculations revealed that the electron density was spread over the iodine and dipyrromethene plane of 9 a,b, whereas in 8 a,b the electron density was distributed on the carbazole group and dipyrromethene plane of aza-BODIPY. The uniqueness of these aza-BODIPY systems is that they exhibit efficient triplet-state quantum yields, high singlet oxygen generation yields, and good photostability. Furthermore, the photoacoustic (PA) characteristics of these aza-BODIPY dyes was explored, and efficient PA signals for 8 a were observed relative to blood serum with in vitro deep-tissue imaging, thereby confirming its use as a promising PA contrast agent.
Description: 9 p.
ISSN: 0947-6539
DOI: 10.1002/chem.201605702
Schools: School of Chemical and Biomedical Engineering 
Rights: © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. This is the author created version of a work that has been peer reviewed and accepted for publication by Chemistry - A European Journal, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [].
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:SCBE Journal Articles

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