Conformational anal. of the solns. of 4 compounds with different spacer length prepared from fluorescein and anthracenecarboxylates showed that there was some weak interaction between the chromophores of the compounds as a result of the flexibility of the spacers. When the anthracenecarboxylate was excited, the singlet excited energy was almost totally transfered to the fluorescein inter- and intramolecularly. However, electron transfer was not observed in the excitation of fluorescein because of the mismatch of the chromophoric planes and because the conformation of the compound in solution did not meet the requirements for intramol. photoinduced electron tranfer.

Key words: SOLUTION, EXCITATION, CONFORMATION, SINGLET, INTERACTIONS