Porphyrin Aggregation on DNA

In 1988, Pasternack and coworkers reported the appearance of an unusually large and exciton split CD band for the meso-substituted porphyrin trans-M [55]. The 

F 1C U RE 7.15 Illustration of helical aggregate of stacked chromophores. Note the distinction between stacked aggregate and cyanine dye aggregates described above the latter only stack to form dimers with aggregate propagating by end-to-end alignment of dimers. Stacked 

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