Coumarin–nucleotide base pairs. Ultraviolet absorption, fluorescence, and photochemical study

Abstract

Bichromophoric compounds containing a nucleotide base and coumarin linked with a polymethylene chain have been synthesized. A hypochromic effect was observed for adenine–coumarin pairs in contrast to the thymine containing compound. The fluorescence intensity of coumarin when bound into these systems was found to be significantly reduced. It has also been demonstrated that excitation energy is transferred from adenine or thymine to the coumarin moiety. Intermolecular dimerization of coumarin residues was observed upon irradiation of an adenine–coumarin pair.