V. Papper, V. Kharlanov, S. Schädel
Dec 1, 2003
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Influential Citations
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Journal
Photochemical & Photobiological Sciences
Abstract
A new dual-fluorescent compound, 5-(oxo)penta-2,4-dienyl- p -( N , N -dimethylamino)benzoate (1), a derivative of dimethylaminobenzoic acid, has been synthesised and studied photophysically. This compound continues the series of potential fluorescent probes for visual and proton-pumping opsin proteins. 1 The photophysical behaviour of this molecule, including charge-transfer interaction in the ground state and dual-fluorescence emission, is similar to that of the previously studied analogue cis -3-(oxo)propenyl- p -( N , N -dimethylamino)benzoate ( cis -2). The presence of several theoretically calculated conformers of compound 2 was suggested to be responsible for the observed strongly red-shifted absorption and excitation wavelength dependence. 1 These photophysical anomalies were also observed for molecule 1, though the models put forward to explain them in the cases of 1 and 2 are rather different. Based on theoretical calculations and experimental results, we propose that some of the stable conformers might be connected with either a charge-transfer complex or mesomeric interactions in the ground state. Upon changing the electronic nature of the oxo-pentadienyl acceptor moiety, e.g . protonation, chemical or biochemical reaction, the charge-transfer absorption disappears, which leads to a dramatic increase in the fluorescence quantum yield.