Synthesis of a new type of dibenzopyrromethene–boron complex with near-infrared absorption property

✍ Scribed by Yuji Kubo; Yu Minowa; Takayuki Shoda; Kimiya Takeshita

• Book ID: 104097395
• Publisher: Elsevier Science
• Year: 2010
• Tongue: French
• Weight: 439 KB
• Volume: 51
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2010.01.070

✦ Synopsis

A new type of p-extended 4-bora-3a,4a-diaza-s-indacene (BODIPY dye), bis(isoindole)-derived benzo-[1,3,2]oxazaborinine 1, has been synthesized by seven-step procedure from 2-methoxybenzoic acid methyl ester. The benzannulation of the pyrrole ring and the formation of a structurally strained intramolecular B-O ring enable the dye to absorb near-infrared light at ca. 750 nm with a molecular extinction coefficient (e) of ca 8.3 Â 10 4 M À1 cm À1 in THF. The absorption properties are discussed on the basis of DFT calculations. Interestingly, a film of 5,5-dihexyloxy derivative 1b, which was fabricated by a spincoating procedure on a glass plate, exhibited a dramatic bathochromic shift of absorbance as compared to the solution, with k max of 922 nm.