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On the triplet states of polynucleotide–acridine complexes. I. Triplet energy delocalization in the 9‐aminoacridine–DNA complex
Author(s) -
Galley W. C.
Publication year - 1968
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1968.360060905
Subject(s) - chemistry , acridine , phosphorescence , photochemistry , acridine orange , triplet state , delocalized electron , fluorescence , flash photolysis , phenazine , excited state , dna , benzophenone , molecule , organic chemistry , kinetics , apoptosis , biochemistry , physics , quantum mechanics , reaction rate constant , nuclear physics
Phosphorescence and fluorescence from the dye in complexes of DNA with 9‐amino‐acridine and acridine orange in a glycerol‐H 2 O glass have been measured at 77°K. The dependence of the p / f ratio for 9‐aminoacridine on the exciting wavelength demonstrates triplet–triplet energy transfer from DNA to dye. The result provides evidence for π electron overlap between the dye and the bases of native DNA. The observation that the magnitude of the enhancement in ultraviolet‐excited dye phosphorescence increases with the base to dye ratio indicates triplet delocalization in the polymer. Preliminary flash experiments provide evidence that this delocalization is not limited by slow diffusion of the triplet exciton. The inability to detect transfer on denaturation of the DNA illustrates the sensitivity of triplet–triplet energy transfer to the conformation of the macromolecular complex.