10.1016/j.tet.2008.08.092
The research focuses on the control of Twisted Intramolecular Charge Transfer (TICT) and Photoinduced Electron Transfer (PET) processes in N-phenyl-9-anthrylcarboxamide derivatives through chemical modifications. The study investigates how the introduction of methoxy groups and a methylene spacer affects fluorescence properties, which are indicative of TICT and PET processes. Experiments involved synthesizing various derivatives with different substituents and measuring their fluorescence and UV spectra in different solvents to assess solvent dependence. The synthesized compounds included N-(2-methoxy or 4-methoxyphenyl)-9-anthracenecarboxamide (1 or 2), N-(2-methoxy-, 4-methoxy-, or 3,4-dimethoxy-phenyl)-9-anthraceneacetamide (3, 4, or 5), and crown ether derivatives 6 and 7. 9-Anthracenecarboxylic acid (9-anthroic acid)was used as a starting material for the synthesis of compounds 1 and 2. HOBt (1-hydroxybenzotriazole)was used as a coupling agent in the synthesis of compounds 3-7. The analysis showed that the TICT process was dominant in compound 1, whereas PET was more significant in compound 2. The introduction of a methylene unit in compounds 3 and 4 modulated fluorescence emissions, and the presence of two methoxy groups in compound 5 enhanced the PET process. The crown ether derivative 7 showed a high response to Mg2+, with a significant fluorescence enhancement upon complexation, attributed to the disruption of p-conjugation. The research utilized spectroscopic techniques to elucidate the photochemical properties and the influence of molecular motion on CT processes, providing insights into the design of chemosensors and fluorescent materials.
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