INTRAMOLECULAR CHARGE-TRANSFER IN DONOR-ACCEPTOR MOLECULES

The photophysical properties of donor-acceptor molecules, "push-pull" polyenes and carotenoids, have been studied by absorption and fluorescence spectroscopy. The compounds bear various acceptor and donor groups, linked together by chains of different length and structure. The position of the absorption and fluorescence maxima and their variation in solvents of increasing polarity are in agreement with long-distance intramolecular charge-transfer processes, the linker acting as a molecular wire. The effects of the linker length and structure and of the nature of acceptor and donor are presented. © 1990 American Chemical Society.