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Internal Dynamics and Energy Transfer in Dansylated POPAM Dendrimers and Their Eosin Complexes

Aumanen, Jukka; Kesti, Tero LU ; Sundström, Villy LU ; Teobaldi, Gilberto; Zerbetto, Francesco; Werner, Nicole; Richardt, Gabriele; van Heyst, Jeroen; Vögtle, Fritz and Korppi-Tommola, Jouko (2010) In The Journal of Physical Chemistry Part B 114(4). p.1548-1558
Abstract
Internal dynamics of dansylated poly(propyleneamine) dendrimers (POPAM, G1-G4) in solution and excitation energy transfer from dansyls to eosin in POPAM-eosin complexes have been studied by time-resolved fluorescence spectroscopy and molecular dynamics (MD) simulations. Combining the results from fluorescence anisotropy and the MD simulation studies suggests three time domains for the internal dynamics of the G3 and G4 generations, about 60 ps for motions of the outer-sphere dansyls, 500-1000 ps for restricted motions of back-folded dansyls, and 1500-2600 ps for the overall rotation. For the smaller generations, the contribution from the restricted motions was not entirely evident. Eosin binding hinders fast rotation of the dansyl... (More)
Internal dynamics of dansylated poly(propyleneamine) dendrimers (POPAM, G1-G4) in solution and excitation energy transfer from dansyls to eosin in POPAM-eosin complexes have been studied by time-resolved fluorescence spectroscopy and molecular dynamics (MD) simulations. Combining the results from fluorescence anisotropy and the MD simulation studies suggests three time domains for the internal dynamics of the G3 and G4 generations, about 60 ps for motions of the outer-sphere dansyls, 500-1000 ps for restricted motions of back-folded dansyls, and 1500-2600 ps for the overall rotation. For the smaller generations, the contribution from the restricted motions was not entirely evident. Eosin binding hinders fast rotation of the dansyl fragments in the largest G4 dendrimer, but the motion of back-folded dansyls is more hindered in the pure dendrimer. Both fluorescence anisotropy and MD results for the G4 dendrimer support the "soft" dendrimer picture with almost free mobility and substantial back-folding of the dansyls of the dendrimers in solution. Analysis of time-dependent spectral shifts of fluorescence reveals 20-30 ps excited-state solvation relaxation around a single dansyl of a dendrimer. Dendrimer-independent excitation energy transfer from 4 to 8 ps from dansyls to eosins in POPAM-eosin complexes G2-G4 was observed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
114
issue
4
pages
1548 - 1558
publisher
The American Chemical Society
external identifiers
  • wos:000273947900002
  • pmid:20058871
  • scopus:75749127436
ISSN
1520-5207
DOI
10.1021/jp902906q
language
English
LU publication?
yes
id
2169008b-774d-4d36-9b1f-c834947f6556 (old id 1541319)
date added to LUP
2010-02-02 14:59:44
date last changed
2018-05-29 09:35:28
@article{2169008b-774d-4d36-9b1f-c834947f6556,
  abstract     = {Internal dynamics of dansylated poly(propyleneamine) dendrimers (POPAM, G1-G4) in solution and excitation energy transfer from dansyls to eosin in POPAM-eosin complexes have been studied by time-resolved fluorescence spectroscopy and molecular dynamics (MD) simulations. Combining the results from fluorescence anisotropy and the MD simulation studies suggests three time domains for the internal dynamics of the G3 and G4 generations, about 60 ps for motions of the outer-sphere dansyls, 500-1000 ps for restricted motions of back-folded dansyls, and 1500-2600 ps for the overall rotation. For the smaller generations, the contribution from the restricted motions was not entirely evident. Eosin binding hinders fast rotation of the dansyl fragments in the largest G4 dendrimer, but the motion of back-folded dansyls is more hindered in the pure dendrimer. Both fluorescence anisotropy and MD results for the G4 dendrimer support the "soft" dendrimer picture with almost free mobility and substantial back-folding of the dansyls of the dendrimers in solution. Analysis of time-dependent spectral shifts of fluorescence reveals 20-30 ps excited-state solvation relaxation around a single dansyl of a dendrimer. Dendrimer-independent excitation energy transfer from 4 to 8 ps from dansyls to eosins in POPAM-eosin complexes G2-G4 was observed.},
  author       = {Aumanen, Jukka and Kesti, Tero and Sundström, Villy and Teobaldi, Gilberto and Zerbetto, Francesco and Werner, Nicole and Richardt, Gabriele and van Heyst, Jeroen and Vögtle, Fritz and Korppi-Tommola, Jouko},
  issn         = {1520-5207},
  language     = {eng},
  number       = {4},
  pages        = {1548--1558},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Internal Dynamics and Energy Transfer in Dansylated POPAM Dendrimers and Their Eosin Complexes},
  url          = {http://dx.doi.org/10.1021/jp902906q},
  volume       = {114},
  year         = {2010},
}