| Abstract
| - ZnAl hydrotalcites containing increasing amounts of 9-anthracenecarboxylate anion (9AC) have been obtained viaan anion-exchange procedure. In particular, intercalated and/or surface-exchanged samples were prepared to studythe effect of the chromophore packing on their photophysical and photochemical behavior. Surface-exchanged sampleswere obtained by equilibrating the carbonate form of the ZnAl hydrotalcite with dilute solutions of 9AC. The nitrateform of the ZnAl hydrotalcite was instead chosen for the preparation of intercalation compounds. The maximumloading of 9AC was found to be 44% of the anion-exchange capacity. The obtained nanostructured materials werecharacterized by chemical and thermal analysis and X-ray powder diffractometry and studied for their photophysicaland photochemical properties. The absorption and emission spectra of the materials revealed the formation of 9ACaggregates. The time-resolved fluorescence properties of the hybrid materials were investigated in bulk and underspace-resolved conditions. The fluorescence decays appeared to be quite complex and were affected by themicroenvironment and the experimental conditions. Generally, a shortening of the main fluorescence decay componentwas observed with increasing matrix loading, thus suggesting the occurrence of nonradiative processes in competitionwith fluorescence at high chromophore concentrations. Indeed, the occurrence of an electron-transfer process to watermolecules, which led to the formation of 9AC radical, was observed spectrophotometrically in the sample with high9AC loading. The electron-transfer process was completely reversible under air-equilibrated conditions.
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