Madhu, Sheri ; Rao, Malakalapalli Rajeswara ; Shaikh, Mushtaque S. ; Ravikanth, Mangalampalli (2011) 3,5-Diformylboron dipyrromethenes as fluorescent pH sensors Inorganic Chemistry, 50 (10). pp. 4392-4400. ISSN 0020-1669
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Official URL: http://pubs.acs.org/doi/abs/10.1021/ic102499h
Related URL: http://dx.doi.org/10.1021/ic102499h
Abstract
A series of boron dipyrromethene (BODIPY) dyes containing two aldehyde functional groups at the 3 and 5 positions have been synthesized in low-to-decent yields in two steps. In the first step, the meso-aryl dipyrromethanes were treated with POCl3 in N,N-dimethylformamide to afford 1,9-diformylated dipyrromethanes. In the second step, the diformylated dipyrromethanes were first in situ oxidized with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and then reacted with BF3•OEt2 to afford 3,5-diformylboron dipyrromethenes. The X-ray structural analysis indicated that the aldehyde groups are involved in intramolecular hydrogen bonding with fluoride atoms, which may be responsible for the stability of the diformylated BODIPY compounds. The presence of two formyl groups significantly alters the electronic properties, which is clearly evident in downfield shifts in the 1H and 19F NMR spectra, bathochromic shifts in the absorption and fluorescence spectra, better quantum yields and increased lifetimes compared to 3,5-unsubstituted BODIPYs. Furthermore, 3,5-diformylboron dipyrromethenes are highly electron-deficient and undergo facile reductions compared to unsubstituted BODIPYs. These compounds exhibit pH-dependent on/off fluorescence and thus act as fluorescent pH sensors.
Item Type: | Article |
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Source: | Copyright of this article belongs to American Chemical Society. |
ID Code: | 104606 |
Deposited On: | 30 Nov 2017 12:31 |
Last Modified: | 30 Nov 2017 12:31 |
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