Sequential energy and electron transfer in polyisocyanopeptide-based multichromophoric arrays

J Phys Chem B. 2011 Feb 24;115(7):1590-600. doi: 10.1021/jp1071605. Epub 2011 Jan 31.

Abstract

We report on the synthesis and detailed photo-physical investigation of four model chromophore side chain polyisocyanopeptides: two homopolymers of platinum-porphyrin functionalized polyisocyanopeptides (Pt-porphyrin-PIC) and perylene-bis(dicarboximide) functionalized polyisocyanopeptides (PDI-PIC), and two statistical copolymers with different ratios of Pt-porphyrin and PDI molecules attached to a rigid, helical polyisocyanopeptide backbone. (1)H NMR and circular dichroism measurements confirm that our model compounds retain a chiral architecture in the presence of the chromophores. The combination of Pt-porphyrin and PDI chromophores allows charge- and/or energy transfer to happen. We observe the excitation and relaxation pathways for selective excitation of the Pt-porphyrin and PDI chromophores. Studies of photoluminescence and transient absorption on nanosecond and picosecond scales upon excitation of Pt-porphyrin chromophores in our multichromophoric assemblies show similar photophysical features to those of the Pt-porphyrin monomers. In contrast, excitation of perylene chromophores results in a series of energy and charge transfer processes with the Pt-porphyrin group and forms additional charge-transfer states, which behave as an intermediate state that facilitates electronic coupling in these multichromophoric systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electrons*
  • Energy Transfer
  • Isocyanates / chemical synthesis
  • Isocyanates / chemistry*
  • Organoplatinum Compounds / chemical synthesis
  • Organoplatinum Compounds / chemistry
  • Peptides / chemical synthesis
  • Peptides / chemistry*
  • Photochemical Processes
  • Polymers / chemical synthesis
  • Polymers / chemistry*
  • Spectrophotometry, Ultraviolet

Substances

  • Isocyanates
  • Organoplatinum Compounds
  • Peptides
  • Polymers