AI Article Synopsis
- Ladder-type pentaphenyl chromophores have a stable, flat structure and exhibit strong fluorescence, making them useful for investigating how electronic excitations interact and spread among molecules.
- Researchers created helical polymers using these chromophores, and found that as the polymer chain length increases, the electronic excitations are delocalized over at least 10 units.
- The study reveals that vibrational motion can cause electronic excitations to shift from being spread out to being localized to almost a single unit, offering new insights into how circular dichroism can be understood in biological polymers like proteins and DNA.
Article Abstract
Ladder-type pentaphenyl chromophores have a rigid, planar π-system and show bright fluorescence featuring pronounced vibrational structure. Such moieties are ideal for studying interchromophoric interactions and delocalization of electronic excitations. We report the synthesis of helical polymers with a rigid square structure based on spiro-linked ladder-type pentaphenyl units. The variation of circular dichroism with increasing chain length provides direct evidence for delocalization of electronic excitations over at least 10 monomeric units. The change in the degree of circular polarization of the fluorescence across the vibronic side bands shows that vibrational motion can localize the excitation dynamically to almost one single unit through breakdown of the Born-Oppenheimer approximation. The dynamic conversion between delocalized and localized excited states provides a new paradigm for interpreting circular dichroism in helical polymers such as proteins and polynucleic acids.
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|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10107742 | PMC |
| http://dx.doi.org/10.1002/anie.202211946 | DOI Listing |
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Article Synopsis
- Ladder-type pentaphenyl chromophores have a stable, flat structure and exhibit strong fluorescence, making them useful for investigating how electronic excitations interact and spread among molecules.
- Researchers created helical polymers using these chromophores, and found that as the polymer chain length increases, the electronic excitations are delocalized over at least 10 units.
- The study reveals that vibrational motion can cause electronic excitations to shift from being spread out to being localized to almost a single unit, offering new insights into how circular dichroism can be understood in biological polymers like proteins and DNA.
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