Abstract: A podand carrying terminal naphthalene as energy donor and anthracene as energy acceptor groups (DSA) has been synthesized. Absorption spectroscopy showed that there was no intramolecular interaction between the two chromophores in ground state. Selective excitation of the naphthalene moiety a decrease in the naphthalene fluorescence is observed accompanied by an increase in the anthracene emission. The results indicate that singlet-singlet energy transfer from naphthalene to anthracene occurs. It is demonstrated that the efficiency of energy transfer is influenced by the solvent polarity attributed to the differences in the conformation about the central C－C bond of the －OCH2CH2O－ unit which is predominantly trans in low-polarity solvent such as benzene but predominantly gauche in high-polarity solvent such as acetonitrile. This in turn is expected to lead to variations of the naphthalene-anthracene separation that effects energy transfer efficiency. It is concluded that energy transfer can be used as a diagnostic tool to probe solvent-specific conformational properties of a D-A system with a flexible bridging ligand.

Key words: Energy transfer;Conformational change;Podand;Dyad;Naphthalene, Anthracene