THE MECHANISM OF INTRAMOLECULAR ENERGY-TRANSFER IN TERMINALLY SUBSTITUTED POLYENE MOLECULES

Absorption, fluorescence and excitation spectra of different terminall y substituted polyenes have been recorded in the UV-Vis region. The ob served intramolecular unidirectional energy transfer from a donor subs tituent to an acceptor at the other end of the chain is influenced but not inhibited by incorporation of a spacer into the polyene chain. In molecules without a spacer, internal conversion within the supermolec ule can explain the observed transfer of energy. In molecules with a s pacer interrupting the polyene chain the observed intramolecular energ y transfer can be explained in terms of Forster transfer.