Xiaogang Liu, J. Cole, Philip C. Y. Chow
Jun 5, 2014
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Influential Citations
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Journal
Journal of Physical Chemistry C
Abstract
7-(Diethylamino)-coumarin-3-carboxylic acid (1) has been used as a laser dye, fluorescent label, and biomedical inhibitor in many different applications. Although this dye is typically used in the solution phase, it is prone to molecular aggregation, resulting in many inconsistent optoelectronic properties being reported in the literature. In this paper, the ultraviolet–visible absorption and fluorescence spectra of 1 are investigated in three representative solvents: cyclohexane [nonpolar and non-hydrogen bonding (NHB)], ethanol (moderately polar and hydrogen bond accepting and donating), and dimethyl sulfoxide (DMSO) (strongly polar and hydrogen bond accepting). These experimental results, in conjunction with (time-dependent) density functional theory (DFT/TD-DFT)-based quantum calculations, have led to the identification of the J-aggregates of 1 and rationalized its different aggregation characteristic in cyclohexane in contrast to that of another similar compound, coumarin 343. We show here that these...