TY - JOUR
T1 - The dynamics of electronic energy transfer in novel multi-porphyrin functionalized dendrimers
T2 - A time-resolved fluorescence anisotropy study
AU - Yeow, Edwin K.L.
AU - Ghiggino, Kenneth P.
AU - Reek, Joost N.H.
AU - Crossley, Maxwell J.
AU - Bosnian, Anton W.
AU - Scheming, Albert P.H.J.
AU - Meijer, E.W.
PY - 2000/3/30
Y1 - 2000/3/30
N2 - The dynamics of electronic energy transfer (EET) for a series of spherical porphyrin arrays based on different generations of poly(propylene imine) dendrimers have been investigated using time-resolved fluorescence anisotropy measurements (TRAMS) in a glass environment. The first, third, and fifth generation dendrimers . consisting of 4, 16, and 64 porphyrin chromophores, respectively, are investigated in this study. We observe a depolarization of the fluorescence in all three dendrimers as compared to the monoporphyrin model compound, indicating that EET takes place between the chromophores within the dendrimers. The experimental TRAMS results were compared to computationally simulated data obtained from the Pauli master equation. For the first generation dendrimer, we find the rate of energy transfer is.well described by Förster theory. Anomalous behavior is observed in the third generation dendrimer where the limiting anisotropy value suggests that energy transfer is confined to only the porphyrins contained within a dendron. Interdendron porphyrin EET is thus unfavorable due to dendron segregation. In the fifth generation dendrimer, the TRAMS data is best explained by a model which includes independent and simultaneous rapid EET between porphyrins contained on the surface of the dendrimer sphere and slow EET between porphyrins in adventitious dendrons found probably either outside or inside of the sphere.
AB - The dynamics of electronic energy transfer (EET) for a series of spherical porphyrin arrays based on different generations of poly(propylene imine) dendrimers have been investigated using time-resolved fluorescence anisotropy measurements (TRAMS) in a glass environment. The first, third, and fifth generation dendrimers . consisting of 4, 16, and 64 porphyrin chromophores, respectively, are investigated in this study. We observe a depolarization of the fluorescence in all three dendrimers as compared to the monoporphyrin model compound, indicating that EET takes place between the chromophores within the dendrimers. The experimental TRAMS results were compared to computationally simulated data obtained from the Pauli master equation. For the first generation dendrimer, we find the rate of energy transfer is.well described by Förster theory. Anomalous behavior is observed in the third generation dendrimer where the limiting anisotropy value suggests that energy transfer is confined to only the porphyrins contained within a dendron. Interdendron porphyrin EET is thus unfavorable due to dendron segregation. In the fifth generation dendrimer, the TRAMS data is best explained by a model which includes independent and simultaneous rapid EET between porphyrins contained on the surface of the dendrimer sphere and slow EET between porphyrins in adventitious dendrons found probably either outside or inside of the sphere.
UR - http://www.scopus.com/inward/record.url?scp=0000556311&partnerID=8YFLogxK
U2 - 10.1021/jp993116u
DO - 10.1021/jp993116u
M3 - Article
SN - 1520-6106
VL - 104
SP - 2596
EP - 2606
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 12
ER -