Triplet Energy Delocalization in Polynucleotide-Acridine Complexes

Year: 1967

DOI: 10.7907/QTHP-8Y47

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Transfer of triplet electronic excitation energy from the purine and/or pyrimidine moities of native DNA and adenine polynucleotides to the acridine dye 9-aminoacridine has been demonstrated at 77 [degrees] K. The occurrence of such transfers indicates that there is pi electron overlap between the purine and/or pyrimidine bases and the dye bound to the polymer.

The acridine dye has then been used as a trap for the polymer triplet excitation energy. The polymer to dye dependence of the base to dye transfer efficiency indicates that triplet energy is delocalized in native DNA and adenine polynucleotides. Kinetic studies provide evidence that the pathlength for triplet energy transfer in native DNA is determined by trapping within the polymer rather than by diffusion.

Delayed fluorescence from the dye bound to DNA has been observed and its origin in the triplet state of the polymer has been confirmed at high polymer to dye ratios. In addition it has been shown that delayed fluorescence can arise from triplet-triplet annihilation between dyes at low polymer to dye ratios.